360 Avocado Growing Basics

Today, we are talking avocado cultivation with Greg Alder, he’s an avocado grower in Southern California, a San Diego County Master Gardener, and he’s  the director of the California Avocado Society. Who better to answer a question about the care and feeding of a Mexicola avocado, in Northern California.  Greg shares practical tips on watering, and common pitfalls to avoid.

We also delve into avocado pollination, highlighting the unique characteristics and taste of various varieties, including Gwen, Hass, and Fuerte.  This is for aspiring backyard avocado tree growers, in many states, both outdoors and indoors. 

We’re podcasting from Barking Dog Studios here in the beautiful Abutilon Jungle in Suburban Purgatory. It’s the Garden Basics with Farmer Fred podcast, brought to you today by Smart Pots and Dave Wilson Nursery. Let’s go!

Previous episodes, show notes, links, product information, and transcripts at the home site for Garden Basics with Farmer Fred, GardenBasics.net. Audio, transcripts, and episode chapters also available at Buzzsprout.

Pictured: Bacon Avocados

 Links:

Subscribe to the Beyond the Garden Basics Newsletter https://gardenbasics.substack.com

Smart Pots https://smartpots.com/fred/
Dave Wilson Nursery
HeirloomRoses.com (with the FRED discount link)

Other links mentioned in today’s podcast:

GregAlder.com, home of the gardening website The Yard Posts.
UC Riverside Avocado info
Farmer Fred Rant Blog Page: Want to Grow Avocados? Good Luck!

Soil Test Links

Texas A&M
Colorado State
UMass-Amherst

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Chapters

• 1:37 Avocado Growing Basics, Pt. 1
• 26:17 Smart Pots!
• 28:02 Avocado Growing Basics, Pt. 2
• 35:10 Dave Wilson Nursery
• 36:32 Avocado Growing Basics, Pt. 3

Transcript

Ep. 360 TRANSCRIPT AVOCADO GROWING BASICS

Farmer Fred:

[0:00] Garden Basics with Farmer Fred is brought to you by SmartPots, the original, lightweight, long-lasting fabric plant container. It's made in the USA. Visit SmartPots.com slash Fred for more information and a special discount. That's SmartPots.com slash Fred.

Farmer Fred:

[0:17] Welcome to the Garden Basics with Farmer Fred podcast. If you're just a beginning gardener or you want good gardening information, well, you've come to the right spot. Today, we're talking avocado cultivation with Greg Alder. He's an avocado grower in Southern California, he's a San Diego County Master Gardener, and he's the director of the California Avocado Society. Who better to answer a question about the care and feeding of a Mexicola avocado but in Northern California? Greg shares practical tips on watering, the benefits of using mulch, and common pitfalls to avoid. We also delve into avocado pollination types, highlighting the unique characteristics of various varieties, such as Gwen, Haas, and Fuerte. This conversation is providing valuable insights for aspiring backyard avocado tree growers in many states, both outdoors and indoors. Today, it's Avocado Growing Basics. We're podcasting from Barking Dog Studios here in the beautiful Abutilon Jungle in suburban Purgatory. It's the Garden Basics with Farmer Fred podcast, brought to you today by SmartPots and Dave Wilson Nursery. Let's go.

Farmer Fred:

[1:31] We'd like to answer your garden questions here on the Garden Basics podcast. There's a lot of ways for you to get questions in. You can, of course, email us, fred at farmerfred.com. Also, you can give us a call. We have a number where you can leave a message. It is 916-292-8964. 916-292-8964. If you go to speakpipe.com slash gardenbasics, you can leave a question there as well. And of course, with the email, you can send along pictures. And pictures are always helpful because a lot of answers to questions about gardening involve me asking you about 20 more questions about what's actually going on. But that aside, here is a question from Andrew in Orangevale. Orangevale is, for those of you who are looking for a home in the Sacramento area and you want a big garden, put Orangevale at the top of your list for properties to search out because it is one of the few areas left in Sacramento.  Where the yards are big.

 They can be acreage, and there's a lot of great gardeners and even some community farmers who live in Orangevale. So it's a great place to live if you want to garden. And he's growing or attempting to grow a Mexicola avocado in Orangevale. And he says, “My wife and I were blessed with finding a property in Orangevale about six years ago that was gardened and maintained for 40 years by a wonderful couple that have also, also since the sale to us, become the best of friends, almost like a second set of parents. The planting here is gorgeous. We have fruit and nut trees that are 25 to 35 years old, and they're wonderful producers.

 The question I have here is about an avocado that's about 10 feet tall now, and it's producing. The size and shape of the fruit indicate that it might be a Mexicola, that it's small, black, with thin skin. So when is the right time to pick these fruits in the Sacramento region. The tree is on the southwest side of our property. It gets full morning sun and then is protected by an oak from the afternoon heat. It seems like it's happy. We have very well-draining soil, and besides the late frost we got last year that took the flowers, and that was my fault for not covering the tree, Andrew says, I think it may be okay where it is. As far as feeding, would you recommend winter citrus food and zinc? Thank you for your time. I've love your knowledge and candor. Looking forward to hearing from you. 

Farmer Fred:

[3:50] Thank you for that That nice letter, Andrew. I appreciate that. Yeah. Anybody who's listened to me over the years knows that I've been an avocado skeptic, growing avocados here in the Sacramento area. The few people I knew 20 years ago or so who were growing avocados here, it would be like one isolated tree that just had the perfect conditions.

 And here in Northern California, especially here in the Central Valley, where you have lots of summer heat and winter temperatures that can drop to below freezing very easily, that is a true challenge for an avocado tree. So let's talk  with someone who does it for a living, who grows avocados, who lives in avocado country down near San Diego in Ramona. It's Greg Alder. He's a master gardener with the Cooperative Extension in San Diego County. He's also a director for the California Avocado Society, and he's been growing food for over 20 years. Greg, it's a pleasure talking with you. I've got to say right off the bat, I do love your website, Yardposts, which is part of your personal page, gregalder.com. Yardposts has a lot of great information on it.

Greg Alder:

[5:05] Thanks, Fred. It's great to talk to you, especially about avocados.

Farmer Fred:

[5:09] And whatever else we talk about. I noticed on one of your pages on Yardposts, you're holding in your hand what look like pluots. And I'm thinking, ooh, maybe he gets enough chill hours. So maybe, as you point out very frequently in your Yardposts website, that all gardening is local and you only talk about what you grow and good for you. Ramona is in kind of a hilly area. If people are familiar with the San Diego area, it doesn't take long to drive east from the beach and you end up in hills and more hills and mountains. Ramona is sort of in like a valley of the mountains there.

Greg Alder:

[5:54] Yeah, that's right. You drive from the beach east and you go north. You first hit the hills and then you go over the first set of hills to get to a sort of valley where Ramona is. And then if you keep driving east further, you'll get into some more hills where you hit towns like Santa Isabel and Wynola and Julian, where they have a lot of apples. And then if you go a little farther, you drop down into the desert.

Farmer Fred:

[6:21] It's an amazing piece of country there. So where you live, because you're over the first range there, you probably still get a lot of marine influence, but I would think that there are some cold snaps there as well.

Greg Alder:

[6:33] Yeah, exactly. If we're just on the west side of the hills, we're getting marine layer virtually every morning through May and June and a lot of summer mornings. But up here where we're at, we get kind of half the marine layer that they do down there. So we get a lot more sun and then it's a good like thousand feet of elevation above the nearest towns to the west. And so we get a good deal more cold in the winter and the air is just a little drier and the heat's just a little higher in the summer. Right.

Farmer Fred:

[7:07] And we should point out that when we're talking about cold, cold is relative in the San Diego area. Cold might be what, under 40 degrees?

Greg Alder:

[7:15]  if you're close to the coast it's really surprising on like two or three mornings when you have some frost on your windshield. but for me in the winter it's not surprising to see some frost on the ground at least once a week. Regarding pluots  i can say it's very nice because i get quite a few chill hours in fact, I've had a couple of nights in the 40s already just in the last couple of weeks here in mid-September. But yeah, for other things, for say avocados, it gets a little dicey. 

Farmer Fred:

[7:56] Well, then you start. Thinking about placement and reflected heat and things like that and avoiding the real cold areas if you've got undulating property.

Greg Alder:

[8:06] Yeah, exactly. Exactly. I'm lucky enough to be on a small hill facing mostly east. And so I've discovered really quickly how high on the hill I have to be to avoid the frost. Down at the bottom, it can be frosty.  up at the top of my hill, just 200 feet away, there's zero frost. So I try to place things appropriately.

Farmer Fred:

[8:30] So you'd have the avocados a little higher up and your pluots down below.

Greg Alder:

[8:34] I should.

Farmer Fred:

[8:36] Isn't that true for all of us? Yeah.

Greg Alder:

[8:40] But  what I really have done is I've got my avocados all over the place from the top to the bottom, which is not good, practically speaking, but it's good for being able to actually watch  the results of the the cold nights and compare things.

Farmer Fred:

[9:01] All right, let's get back to Andrew's question here about growing the Mexicola, or at least he thinks it's a Mexicola. And based on his description of the Mexicola avocado, that it's thin skinned, it's small, it's black, it probably is a Mexicola.

Greg Alder:

[9:16] Yeah, it sounds like it. I don't know if, especially if he, well, he didn't buy the tree, I suppose. But if it was planted as a grafted tree, there's nothing that's sold that's like a Mexicola that isn't Mexicola that I know of. And yeah, that variety has been around forever. The small, black, thin-skinned variety. It doesn't surprise me at all to hear that he had some damage to the flowers because one of the downsides of Mexicola is that it flowers really early, meaning in the winter. It doesn't wait until the late winter, early spring like most avocados. Mexicola will flower in the middle of winter, which is not good because the flowers are very sensitive to the cold temperatures. Even though the tree as a whole, the foliage of a Mexicola tree, say, is pretty tough in the cold for an avocado, but the flowers are not.

Farmer Fred:

[10:08] One thing I was reading about the Mexicola as far as its leaves go, do they have sort of a licorice or fennel-like smell to them?

Greg Alder:

[10:15] Yeah, if I recall correctly, I haven't, I can go crush one real fast right now. But yeah, I think they do, if I recall correctly. The new leaves have more of a yellowish color rather than a red. Some other varieties have more of a red color to their new leaves, but Mexicolas don't. They're more just a lime green, yellowish color.

Farmer Fred:

[10:41] Not that it's a California native, but the seedling was developed in Southern California in Pasadena.

Greg Alder:

[10:47] Yeah, in that sense, it is a California native because, yeah, the first Mexicola tree was grown in Pasadena.

Farmer Fred:

[10:54] Yeah, at the Coolidge Rare Plant Gardens. Now, I know the University of Riverside, UC Riverside, is the center for avocado knowledge. And I know that at their excellent avocado website, and we'll have a link to it in today's show notes, they they talk about the fruiting season for the Mexicola probably in riverside is august through october. would that be true throughout california?

Greg Alder:

[11:21] Yeah it would i think it would be roughly true throughout california and it varies a little bit year to year according to the weather. but i've eaten mexicolas in a lot of different parts of southern california  and that always holds true whether it's close to the beach or inland like riverside, So yeah, basically late summer, the fruits start to blacken and they're ready to go. And then,  they can hold on the tree into maybe October, but unfortunately, Mexicola, like some other similar varieties, like one called Mexicola Grande, they don't have a good hang time. They'll start to just drop from the tree at the end of summer, early fall. And so you kind of got to, there's a short harvest window with, you might get them into October. You might have all your fruit on the ground by October.

Farmer Fred:

[12:16] And the Mexicola variety, is that more of an early bearing fruit in the long avocado season that there is?

Greg Alder:

[12:24] Yeah. In fact, it's the earliest one that I know of.

Farmer Fred:

[12:27] I know UC Riverside says it's very heat and cold resistant, which is appealing to avocado growers. Well, I should say people trying to grow avocado trees, say, north of Fresno or so. It's very heat and cold resistant, and it's cold maybe down to 20 degrees or so, which seems improbable.

Greg Alder:

[12:48] Yeah, I haven't tested that myself, but yeah, that's what I'm told. And I've heard reports that it's pretty darn tough. I've only seen 25 degrees at my place where I've been for 11 years now, and Mexicola has been plenty tough at 25.

Farmer Fred:

[13:08] Well, that's a good candidate then for up here. And I say this about all fruit, the stone fruits, deciduous fruit trees, and avocados, too. And tomatoes, for that matter. As far as if your only experience tasting fruit or tomatoes or just about anything in the vegetable section is what you've tasted is what you've bought at the supermarket, you haven't tasted fruit. Because the flavors of freshly picked fruit are overwhelmingly outstanding.

Greg Alder:

[13:44] I was just thinking about this yesterday because I was looking at some fruit in the grocery store and just looking at the prices and thinking, wow, my yard is so valuable. And this doesn't even take into account how much better the stuff in my yard tastes. Yeah. And Mexicolas in particular, they have an excellent flavor. Some people think it's their favorite flavored avocado. It's got a really nice, rich flavor. It has some other downsides, but it's a really good avocado in terms of the flavor. And if you're just buying, say, Mexican Hass avocados in the grocery store, you'll find that they vary a lot. Sometimes they're really bland. Sometimes they're pretty good.

Farmer Fred:

[14:30] So I would imagine also that perhaps the more progressive supermarkets in your area, as well as farmers markets, have a wide variety of avocados that people can try. Whereas up here, it's all Hass. It's all Hass. And I feel sorry for people who haven't tried these other varieties.

Greg Alder:

[14:49] You know what, Fred? I wish that were true, but sadly, you go to 99% of the markets down here, and that's also the only thing they have is Hass. It's so sad. It shouldn't be that way. We've got varieties down here that we produce. You'll go to a market and there's just three miles that way, there's an avocado grove that could be producing fruit, different varieties year round, but they've got just Hass from California or just Hass from Mexico or Peru or something. And yeah, it's sad to say, but that's what we've got down here too. There are some exceptions. I saw some of the Reed variety in a market a couple weeks ago, but mostly, sadly, it's just Hass down here too.

Farmer Fred:

[15:36] I can understand that, but I would think the farmer's markets in your area, when the fruit is in season, would be a wonderful place to shop.

Greg Alder:

[15:44] Yes, that's where you can find the other varieties if you get a good farmer's market vendor. And they often don't have a dozen varieties, but throughout the year, they'll probably sell five or so. So that's good.

Farmer Fred:

[15:57] Andrew, in his question about growing the avocado tree, pointed out some interesting facts about where he's growing it there that indicate, yeah, you've got it in the right spot, Andrew. The tree's on the southwest side of the property. It gets full morning sun that is protected by an oak from the afternoon heat. It has very well-draining soil and looks like it's doing okay.  And he had that question about fertilization of avocado trees that I'd like you to talk about. He said, would you recommend winter citrus food and zinc? Take us through your regimen for feeding your avocado trees.

Greg Alder:

[16:31] Okay. Well, I'm a little unconventional with my trees in particular. So I'll tell you what I do, and then I'll tell you what other people do that also get great results. I simply mulch my trees with wood chips and a bit of compost that sometimes has some chicken manure in it just because I have chickens. And that's all I do. And that's all I've ever done with my trees. And they do just fine. But I know other people who do all sorts of different, fertilization routines and they get good results too. I think that there's no one best way to  fertilize avocados. I think you can do it a lot of different ways and probably the easiest thing to do is just have a look at your tree and say are the leaves nice and green? is it growing?

Okay, then I'll keep doing what I'm doing, which may be like me, just put some arborist tree trimmings underneath the tree and that's good enough. In terms of Andrew's question about winter citrus food and zinc, generally in the winter, no one does any kind of fertilization for avocados just because the soil gets cold and the tree isn't taking up as much of that stuff and that stuff isn't breaking down as quickly. And so, at least around here, most people start to fertilize around late February, March, and then they sort of quit in October or so. Now, if you're just putting wood chips down, though, you can do that any time of year, and it doesn't matter. And regarding zinc in particular, zinc is probably not needed. It will sometimes show up as a deficiency in avocado trees if the pH of the soil or water is a little too high, but it's better to just try to deal with the pH issue rather than trying to apply zinc. If you actually see a zinc deficiency, it would show up as really small, Yellow, chlorotic-looking young leaves on an avocado tree, then I would deal with the pH through putting down some elemental sulfur pellets. But you'll probably not even run into that situation. I've rarely seen it. And sometimes when I have seen it, rather than a pH, it's actually like a compacted soil and overwatering problem.

Farmer Fred:

[19:07] Well, in this business we're in of answering gardening questions, I always maintain that if your answer 95% of the time is “it's a watering issue”, you'll be right. Yeah.

Greg Alder:

[19:18] Yeah, especially with avocados. I'm telling you, if you get the watering right for avocados, the tree's going to grow just perfectly 95% of the time. There's not much else you have to do.

Farmer Fred:

[19:30] It sounds like it's a very persnickety tree in that it likes moist soil, but it needs good drainage.

Greg Alder:

[19:36] Yeah. Avocados are the most finicky tree that I know, and especially related to their soil drainage and water needs. Here's the thing. Don't water them in the winter. That's for sure. And then when you do plant, check the drainage first. First, dig a hole and fill that hole with water and see that it drains out within a day at the longest. And if it doesn't, either plant at a different spot or you need to build a mound to plant it on. So plant it right in the first place. And then while it does require a lot of water through the summer to be happy, if you have the sufficient drainage, then you don't really need to worry about overwatering. But if you don't have the drainage, then you're going to run into trouble because you can't really stretch out the waterings too much to rectify the drainage problem because then you're just going to be making the tree too thirsty in between watering. So you really just got to get the drainage right in the beginning. And then the watering issue becomes a lot easier, a lot more forgiving. 

Farmer Fred:

[20:52] You mentioned not watering in the wintertime. I think that would be only if you get the normal amount of rain that we usually get here in California in the wintertime.

Greg Alder:

[21:01] Yeah, yeah, true. But I'll say that even down here, if we don't have rain for three weeks in the winter, I only start thinking about watering my avocado trees after three weeks of dry. And I'm on a sandy, loam, hillside soil, and they're fine. So I would say up where you're at, where your soil's, I'm just guessing, correct me if I'm wrong, but your soil's probably loamier, siltier, maybe clay, more clay, and it's probably deeper.

Farmer Fred:

[21:35] Don't forget the rocks.

Greg Alder:

[21:36] Yeah. And you generally get more rain than we do down here. I would guess that it would take something like a month of dry in the middle of winter before you really need to water an avocado. But that's just a guess.

Farmer Fred:

[21:52] Yeah, we get maybe in a normal year 17, 18 inches of rain here. And I think down there you get, what, three to six inches of rain?

Greg Alder:

[22:00] Yeah, it really varies from the coast to the inland hills and from the south to the north. But I'm a little better. I get like 15, 16 inches where I'm at. Yeah, because I'm in the foothills.

Farmer Fred:

[22:13] All right. Now, we should point out, too, and I want to reemphasize the fact that you're mulching your trees. Now, please stop me if you've heard this before, folks. But frankly, mulch solves a whole host of issues. It feeds the soil as it breaks down. it allows moisture to remain longer as long as you have good drainage.

Farmer Fred:

[22:33] It also inhibits weed production. And one other thing that we talk more and more about as far as the benefits of mulch go, and that is when it rains and you don't have a covered soil, if it's just bare soil, the pressure of those raindrops can really compact your soil. So that mulch acts like like sort of nature's drip irrigation system by taking the blows of that rain that's coming down and then slowly letting it percolate into the soil. So a few inches of mulch around your trees, don't let it touch the trunk, can do a whole world of good. Now, avocados are not a citrus tree, correct?

Greg Alder:

[23:12] As far as I know.

Farmer Fred:

[23:14] Okay. Okay. Because I've heard about citrus trees that you don't want to have much mulch around citrus trees because the roots don't like the mulch. And I kind of disagree with that. I still think a thin layer of mulch, if it's only an inch or two around citrus, is fine. And around avocados, I imagine you have, what, four to six inches of mulch.

Greg Alder:

[23:34] Yeah, yeah. I mulch both my citrus and avocados. But the avocados seem to benefit from the mulch a little more than the citrus. And when I put the mulch on to my avocados, I try to sort of be efficient and put it on a thick because it quickly disappears. So you might put on, I'll put on six, eight inches at a time, even more sometimes. And then by the end of the year, say, you'll only have a couple inches remaining. And avocados, as much as every fruit tree, I think benefits from mulch. Avocados like it even more because what you'll find is if you have a mulched avocado tree that's especially thickly mulched, you'll, after, say, a year of that mulch being on the ground, you'll be able to scratch the mulch away and you'll find white-tipped avocado roots actually growing out of the dirt up into the mulch because they love all of the oxygen that they can access in that both moist, cool and airy environment right there at the soil mulch interface so that's  the sign of a really happy avocado root system is is when they can access that kind of environment.

Farmer Fred:

[24:55] You may find some earthworms as well

Greg Alder:

[24:57] Yeah yeah definitely i would.

Farmer Fred:

[25:00] I would think that anybody starting to plant avocados wherever you may live you're taking a chance. but i would definitely get a soil test done, a complete soil test to figure out what your soil needs before you plant that tree.

Greg Alder:

[25:14] Yeah, it couldn't hurt. It definitely couldn't hurt. I mean, at the same time, you know, if you think about what avocados, the soil that avocados want, like the perfect soil, it'll be slightly acid, like a 6.5. And, you know, you can go on with the details, but the truth is They're a little bit more flexible than you might think. And so I don't have 6.5 pH soil. I'm about 7, 7.5, and my avocados do fine because it does depend a little bit on the rootstock that the avocado tree is on. Some rootstocks do better in different soil conditions. So that being said, a soil test could never hurt.   it might save you a lot of grief down the line to know what you're dealing with first. Yeah.

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AVOCADO GROWING BASICS, Pt. 2

Farmer Fred:

[27:45] We're talking with Greg Alder. He has a wonderful web page. It's called Yardpost, and it's a website dedicated to Southern California gardening, especially growing of avocado trees. A lot of great information there. It's at gregalder.com. And we talked about the taste of avocados and how they can vary. And here in Northern California, we tend to plant the avocado varieties or try to grow the varieties that do have good cold hardiness. And besides the Mexicola we talked about, there could be the Pinkerton, the Bacon, the Jim, Zutano, Fuerte, Sir Prize, and Stewart seem to have some success here in Northern California, as well as the Duke, which I know very little about, but I know Dukes that grow in the wild in the northern end of the Sacramento Valley. So go figure. Are there any other cold-tolerant avocados that you can think of?

Greg Alder:

[28:42] Not common named varieties. you named  all the good ones  that i know of, especially the ones that i know just from reports from people actually growing them up there who've had good success are especially bacon and some fuerte and definitely duke. yeah if if i were up there i would plant i think the first thing i would do is plant a bacon maybe second i'd try a fuerte And then I'd go from there and I'd test out some others, including I might even try a GEM, which is a  new-ish variety developed in the UC Riverside program. But it's just a little bit tougher than a Hass, even though it's not significantly tougher than Hass. But if I had the right little microclimate with maybe a south-facing wall to plant near or a little bit of south-facing slope or if I was up, maybe toward the foothills, out of the flats of the valley, I'd think about trying that one too.

Farmer Fred:

[29:52] Yeah, you have to develop your own little microclimate to get avocados to grow. Here, where I see successful avocado trees, they all seem to have the same location of protection from sun, afternoon sun especially, and wind, which, because the delta breezes regularly come through every summer afternoon and that drops the humidity level. a lot of reflective surfaces help, too. It could be a south or west facing fence or a nearby concrete patio, something like that just to give it some winter warmth.

Greg Alder:

[30:25] Yeah, that stuff helps a lot. I think also what I've been told is that some varieties are particularly prone to losing a lot of their crop in the early Early summer heat, like, say, in June, when you get the first heat wave that might get up into the triple digits in June, the small fruit that's just developing on a tree is really sensitive to that high heat. And so... If you're lucky enough to get a tree to fruiting size and you get that first crop and then you get a heat wave in June, it can be beneficial to spend a day or two, if you can, kind of protecting that young fruit with maybe spraying down the tree with some water to cool it down or some kind of shade, if you can do that. I've heard that's one of the problems with some growers down in the San Joaquin Valley is keeping their crop on in that early summer heat. I get a little bit of the same problem down here because I'm far enough inland to get early heat waves down here too.

Farmer Fred:

[31:41] There are newer commercial varieties being developed that can take a lot more of the conditions we have here in Central and Northern California. A lot of it is due to Mary Lou Arapaia, who works for UC Riverside. She is an avocado breeder, and she has helped develop varieties, commercial varieties, for the Central Valley and even here in Sacramento County in the Delta, which is really windy. And I'm amazed at the success these growers are having.

Greg Alder:

[32:11] Yeah, Mary Lou, she's had her eye on the Central Valley for years now. And she's been testing varieties up there for years as well. Mainly, the UC's sort of research grounds is in Lincove, kind of near Exeter, Lemon Cove, that area there. Yeah, she's been able to test both the cold tolerance and the heat tolerance of some of the varieties that she's been coming up with. And that have been developed by our predecessors like Gray Martin and Bob Berg. So she's testing the GEM and she's been testing the latest release from the UC program, which is now called Luna. She's had her eye on helping people find varieties and find ways to grow avocados in the Central Valley as a whole, because the water's better, the water's cheaper, the land's cheaper. And there's a lot of really good farmers that would love to grow avocados there if they could.

Farmer Fred:

[33:16] Yeah, as long as they have senior water rights, they'll be fine. That's the issue for a lot of Central Valley growers. And we're seeing more Central Valley growers looking for alternate crops because they have the land, but they don't have the water. And one of the crops of interest that is being planted, at least tested in the Central Valley now, is agave, a succulent. And you think of agave, oh, they're going to make tequila. Well, actually, there's I don't know how many dozens of varieties of agave that there are, but these particular varieties of agave that they're looking at here would either go to Mezcal, which is an alcoholic beverage, if you haven't tried it yet, or for wine. And that's interesting. So there might be a new member of the California wine family with agave.

Greg Alder:

[34:06] Wow. Well, and I guess agave takes the heat and the cold, huh? Oh, yeah.

Farmer Fred:

[34:12] Yeah, it's fine. The big selling point is, whereas an almond tree would take 30 inches of water per year, the agave only needs three inches of water per year. The problem is, it's years before you get a crop, and then its another few years, if you're distilling it for mezcal or for wine, and it is labor-intensive, too. So you've got that going against it. But we'll see. California agriculture is a very interesting topic just for all the variety that they try and they have to try because of changing climate conditions.

DAVE WILSON NURSERY

Farmer Fred:

[34:50] Fall is in the air, the perfect season for planting and planning. And if you're planning to buy and grow some fruit trees this fall and winter, you need to check out the Home Garden page at DaveWilson.com. That's Dave Wilson Nursery, the nation's largest grower of fruit trees for the backyard garden. At DaveWilson.com, you're going to find planting tips, taste test results, fruit variety recommendations, and links to nurseries in your area that carries Dave Wilson and fruit trees. Just go to DaveWilson.com, click on the Home Garden tab at the top of the page. There, you're going to be just a click away from their informative YouTube video series. Especially popular in that video lineup is Dave Wilson Nursery's Tom Spellman explaining Backyard Fruit Tree Basics. Viewers have raved about that episode, calling it absolutely the best single video for growing backyard fruit trees. Check it out before you plant. The Backyard fruit tree basics video. It's on YouTube. Find a link to it after going to the home garden tab at DaveWilson.com. Click on the getting started link and you're on your way to your best fruit garden ever. Your harvest to better health begins at DaveWilson.com. 

AVOCADO GROWING BASICS, Pt. 3

Farmer Fred:

[36:08] Let's get back to our conversation about avocado growing basics with master gardener and avocado grower, Greg Alder.

I want to get back to the taste of these other avocado varieties, because if people are only used to the taste of a Haas avocado that you'd find in a grocery store. You described what the Mexicola tastes like. What about these other varieties that have more cold tolerance, like the Bacon or the Zutano or the Fuerte or the Stewart?

Greg Alder:

[36:31] Yeah, they're all a little bit different, which is fun. It just has a baseline. I would describe Hass as a little bit nutty and very smooth and no fibers, no strings. And then on the other hand, if we just go back to the Mexicola for a second, the Mexicola can have a kind of anise or black licorice taste to the background. And especially that taste is in the skin. And some people do just eat the skin. Since it's so thin and it has a bit of that anise flavor, you won't find that anise flavor in Hass. You won't find it in Bacon. Bacon has actually more of a sweetness in the background to its flavor. For me anyway, that's what it tastes like to me. It doesn't have quite as much of an oil content as Hass or Mexicola, so it's a little bit lighter. I mean, people can describe it as more bland, but I think as long as you let it mature long enough, it's not really bland. It's a nice fruit, but it is a little bit lighter in flavor.

Greg Alder:

[37:44] Zutano, I would say, is even a bit less flavorful than Bacon, but it doesn't really have the sweetness. With all those though, with Bacon and Zutano, you can get a little bit of strings or fibers, especially toward the stem end and near the skin. And so they're not quite as smooth all around throughout the flesh as a Hass. Fuerte can have a few fibers as well, but it's mostly smooth. And it has a thin skin just like Zutano and Bacon. But the flavor of Fuerte is superior to Bacon and Zutano. I think it's, some people think it's the most, the best tasting avocado. And I would not disagree with that. It's an amazing tasting avocado. It's definitely the best or one of the best, maybe, you know, in the top five, I think, of everyone who likes avocados. And it's a little richer than the Bacon or Zutano. It's more similar to Haas in its richness.

Farmer Fred:

[38:57] And now people are yelling at their phones, what was that variety? What was that variety? Fuerte.

Greg Alder:

[39:03] Yeah, Fuerte is the variety that built the California avocado industry starting in the early 20th century. It was brought up from Mexico in 1911. And the Papanos in Altadena, Pasadena area, they grew it and spread it around. And it took over the commercial, the budding commercial industry back in the 20s, 30s, 40s. And only Hass took over the commercial industry as a dominant variety in around the 1970s. So for roughly 50 years, Fuerte was the commercial variety. And you find there are lots of big old Fuerte trees up in the Bay Area, throughout Southern California. And it's just an awesome variety.

Farmer Fred:

[39:57] Well, since you brought it up, do you have a top five list of the best tasting avocados besides Fuerte?

Greg Alder:

[40:03] Oh, man, that's so hard. I don't know if I have a top five, but I'll rattle off a few that I think are definitely top tier. I'll say, yeah, sometimes it's hard to distinguish between how good the fruit itself tastes and whether or not you should grow it. Because some really good tasting avocados are not really worth growing in certain locations because the tree isn't great or it's not so productive or there's issues with the trees. But I'll just go with excellent tasting fruit without considering the trees themselves.

Farmer Fred:

[40:42] Okay, but give us some warnings if it really is a really persnickety tree.

Greg Alder:

[40:46] Yeah, okay. I'll make some caveat notes about the trees, too. Well, Hass overall, if I had a single tree in my yard and I could grow Hass, I would grow Hass because it's just all around an excellent tree. I would also grow Gwen. Gwen is all around excellent. 

Farmer Fred:

That's G-W-E-N? 

Greg Alder:

[41:17] Yeah, that's right. Yeah, that's right. And I would also grow a Sharwil. S-H-A-R-W-I-L (also known as the Kona Sharwil). The fruit is amazing. The tree isn't the best just because it's not always the best producer in some locations, but the fruit is amazing. I would grow Reed. Reed is the best summer into fall avocado. It's a big round avocado and we're eating it right now. And my kids yesterday just said, this is the best. It's it's just awesome and the tree is is excellent as well it's a very good producer as another tree that i would grow gem is an excellent variety it makes a lot of fruit the fruit is very good it has a couple of other nice qualities which is the tree is a little bit more compact and and denser than some other trees like has and the fruit kind of grows a little bit more on the inside of the canopy. The leaves cover the fruit a little bit better than some varieties like hasps. And so the fruit will get less sunburn.

Farmer Fred:

[42:24] I have a question about the GEM. Are you saying gem like in G-E-M or jim like in J-I-M?

Greg Alder:

[42:31] Yeah, it's G-E-M and it's actually an acronym. The person who named the variety is Gray Edward Martin. And so technically speaking, it's a capital G, a capital E, a capital M for his initials. He was the one who developed it, selected it, along with his mentor, Bob Berg. They were both working for the University of California when they developed that variety.

Farmer Fred:

[43:04] I guess we should point out there is no variety called BB. Right.

Greg Alder:

[43:08] Beavis, actually, there probably is, just because there are so many varieties. I bet you could find one. However, I should note that Bob Berg also developed the Gwen variety that I mentioned a minute ago, and he named that variety after his wife, Gwen Berg.

Farmer Fred:

[43:28] Smart man.

Greg Alder:

[43:29] Yeah, especially because it's an amazing variety.

Farmer Fred:

[43:32] And I think Fuerte's on that list as well.

Greg Alder:

[43:35] Yeah, I would grow Fuerte too. The only downsides with Fuerte are that they like to be a big tree and they are not always very productive. There's two challenges with Fuerte. One is some trees just don't produce well. It's a bit of a mystery that's always been around. You just get some Fuerte trees that for whatever reason, they don't produce well. They have defects in their flowers. there are lots of different ideas about why and the second reason is they're a what's called a B- flower type avocado. Any B- flower type avocado is going to be overall more of a risk for fruit production than an A- type flower avocado so i could get into that if you want.

Farmer Fred:

[44:26] I know. I’m thinking that this scenic bypass has a lot of potholes in it. But it Is on my list list of things to talk about, but just to repeat, the ones you just mentioned, your top five list has turned into a top six,

Greg Alder:

[44:39] And that's fine.

Farmer Fred:

[44:40] Fuerte, Haas, Gwen, Sherwil, Reed, and GEM.

Farmer Fred:

[44:48] I want to go back to taste for one question. I have a friend who once posited the theory that all people fall into one of two categories. They're either crunchy, or they're creamy. They either like just creamy treats or they just like crunchy treats. Now, Hass would be a creamy treat. Is there a crunchy treat in the world of avocados?

Greg Alder:

[45:12] I like that. Yeah, I like that. Yeah, there are. There are some varieties that have a firmer flesh, and a couple that come to mind are Gwen and Lamb. Those varieties both have a firmness to their flesh. Flesh, yeah. I would say on the creamier side would be Hass, Reed, Fuerte, yeah. Although you can't cut open a Fuerte as early as it is ripe and get it more firm. But yeah, there are some not quite crunchy, but yeah, firmer fleshed varieties. Lamb and Gwyn come to mind.

Farmer Fred:

[45:55] Yeah, as I go through life, I find that comparison more and more true with the people you meet. Is it the Lamb avocado or the Lamb-Haas avocado?

Greg Alder:

[46:07] Yeah, when they patented the variety, they named it Lamb slash Haas. And so technically speaking, the variety is Lamb Haas. But I know very few people who call it by that full name. I also think it's a shame that they named it that way because it's just confusing. It's not a Haas and it doesn't really have such a close relationship with Haas. In fact, it's a seedling of the Gwen. Gwen is a seedling of a variety of Phil and Phil is a seedling of Hass and so it is a distant relative of Hass but it's different from Hass and it should be more distinguished. let's just call it Lamb rather than lamb hass.

Farmer Fred:

[46:56] I'm thinking we can get into this A flower versus B flower conversation about avocado trees simply. Let me point out in the interest of time here that avocado pollination is increased theoretically when you have two types of avocado trees, one with an A flower and one with a B flower. These flower types open at different times of the day. The California Rare Fruit growers like to say that avocado flowers are either receptive to pollen in the morning and shed pollen the following afternoon, that's a type A. or, are receptive to pollen in the afternoon and shed pollen the following morning, that's a type B. And according  to charts I've seen, the type A flowers include Mexicola and Pinkerton, whereas the B flowers would be the Bacon, the Jim, Zutano, Fuerte, Sir Prize, and Stewart. Now, having said that, if you're familiar with Ed Laivo formerly of Dave Wilson Nursery, a fruit tree expert, he has his own YouTube channel where he talks fruit trees. He says avocado trees, especially here trying to grow in Northern California, are so stressed that they will produce both type A and type B flowers on one tree. Is that true?

Greg Alder:

[48:10] I don't know because, yeah, maybe what he's getting at is the fact that you can go up to a tree, especially at certain times of the day, and you can find both male and female flowers open on that same tree at the same time. And so in that sense, you might want to say... It's acting as both an A type and a B type, even though that wouldn't be technically accurate because the A and the B refers to its patterns, its general patterns of opening. And that pattern is really only accurate when the temperatures, the night and day temperatures are within a range, not to get too far into the weeds.

Greg Alder:

[48:58] But as far as my observations go, Every variety does fall into an A or a B type pattern, given that the temperatures are within a certain range. But especially when it's colder, and especially when the nights are colder, the avocado flower openings of all varieties start to get funky. They start to misbehave. The only time you can really accurately describe an avocado tree's flowering type or pattern is when the nights are relatively warm and the day temperatures are also relatively warm. Probably the mean temperature needs to be above 65, maybe close to 70, and then you could accurately assess the variety's flowering pattern as A or B.

Farmer Fred:

[49:49] Yeah, a mean of 70 would mean it could have a low of 40 and a high of 100, but probably that isn't the best situation.

Greg Alder:

[49:55] Yeah. Basically, if you want to look at an avocado tree and say, is this an A or a B, you want to do it in the late spring toward the end of the flowering season when the temperatures are generally warmer, and you want to do it during a warm period. And then you want to do it both in the morning, no later than around 10 a.m., and again, you want to look at the tree in the late afternoon, around 4 p.m., 5 p.m. Because in the middle of the day, the flowers are opening and closing, and they're in different phases, and you'll get a bad read, so to speak. You've got to do it in the morning and the evening.

Farmer Fred:

[50:41] That's good advice. Nice. Now, if people are wondering what avocado flowers look like, I have a post up at the Farmer Fred Rant blog page entitled, “Avocado Trees in Sacramento. Good luck”. And I have pictures of what the flowers look like and a lot of the varieties listed too. So if you are in Northern California and Central California and you think you want to grow avocados, take a look at that page. And I'll have a link to that in the show notes as well. But before we leave that topic, a lot of the avocado trees that I see that are successful around here in Sacramento County, it's a single tree. There aren't two trees.

Greg Alder:

[51:19] Yeah, I think it's a sad thing that somehow the rumor that you need more than one tree to get fruit or a good fruit production from an avocado tree is necessary. It's just not true. There's lone trees all over the place that are producing just fine. The short of it is some varieties do produce better as lone trees than others. For example, Hass produces just fine as a lone tree. Bacon produces just fine as a lone tree, but Pinkerton doesn't produce all that well as a lone tree comparatively. So, yeah, so it depends on the variety. And if you have more than one tree, you're only going to potentially get more fruit production. It can never hurt to have more than one, but you don't need more than one.

Farmer Fred:

[52:11] Well, then you have the problem of room, and that brings up the other question. Can you prune avocado trees to keep them at a certain height?

Greg Alder:

[52:21] Oh, yeah. I prune all my trees. I don't let them get—the biggest tree I allow, let's say, is a Hass tree, and it's about 16, 17 feet. And I just keep it there by pruning it once heavily each winter, late winter, and then once or twice again sometime in the summer, real light prunings. But I was just at a grove of the Reed variety where this grove has trees planted five feet apart. They're pretty columnar trees. The Reed variety can grow that way. I would say they're probably allowed to be something like 10-ish feet tall, and they're just pruned heavily every year. And you can do that with avocados. They take really well to pruning. You just want to avoid doing any heavy pruning in the summer because they'll get sunburned. You want to do your pruning, the ideal time, is the very end of winter or the very early part of spring. That'll avoid the sunburn problem.

Farmer Fred:

[53:33] Something I point out on this show very often is kids, don't try this at home. As far as the spacing of avocado trees, don't plant your trees five feet apart. Give yourself room to walk around the trees, even if you're maintaining their height at a certain height, where you can throw a row cover over it or a frost cloth over it. You need that room. And besides that, they need good air circulation, too.

Greg Alder:

[53:56] Yeah. There are lots of different ways you can manage it. It depends on the space that you have. Like you said, I've got trees that are planted very far apart, 25 feet apart, because I want them to get wide. and then I've got other trees that are planted just a couple feet apart. I've got some mature trees that are only seven and a half feet apart and that's okay as long as you're willing to prune them sufficiently on a yearly basis. I also know some people, I've seen some trees that are managed where two trees, even three trees are planted in a single hole so the trunks are literally six six inches apart you can do that too if you want to try to get multiple varieties into a small space it just becomes a management challenge like are you up for the management challenge of pruning those trees when they all are going to grow at a slightly different rate and you got to make sure you can distinguish between the different varieties so you're not ultimately letting one  of the varieties take over, but there's lots of creative ways you can go about arranging and mixing varieties to get what you need for pollination or for an extended harvest season and so on.

Farmer Fred:

[55:14] It's good to know you can prune your avocado trees. The folks at Felco and Corona, thank you for keeping them in place.

Greg Alder:

[55:20] Yeah.

Farmer Fred:

[55:20] All right. Now, we've been talking about growing avocado trees here in USDA Zone 9, basically. I would think where you are, are you zone 10 or zone 9 because you're over the hill?

Greg Alder:

[55:33] Yeah, I think I'm not sure if I'm 9A or 9B. I don't know. I still like the old Sunset zones better.

Farmer Fred:

[55:43] Well, that's even more confusing for you. Are you in Sunset Zone 20 or 21?

Greg Alder:

[55:48] Yeah, there you go. Yeah, I think I'm on the edge of 20 and 21. Okay.

Farmer Fred:

[55:53] Yeah. It would be nice if Sunset would update their Sunset Western Garden book for us growers and gardeners out here, because it really is a very thorough delineation of what can grow where, because they have 24 growing zones listed. So yeah, good luck on that. Speaking of growing avocado trees, there are people listening in 49 other states who are saying, what does this have to do with me? Why should I listen to this? Where, Greg Alder, have you heard about avocado trees growing?

Greg Alder:

[56:26] I could probably think of a dozen states in the US where I know people are at least trying them outside.

Greg Alder:

[56:34] Maybe not a dozen, sorry, maybe half a dozen. But I know a lot of other places where they're growing them either indoors or in a greenhouse of some sort. I know a grower up in Oregon who has a greenhouse. I know some people up in Washington state who are growing some in a greenhouse and outside. There are people growing them in Arizona, in Texas, of course in Florida, as well as Georgia. I even spoke with a grower a month or two ago who's growing them in South Carolina. I know someone who's growing them in Louisiana. And so, yeah, I mean, people are testing them out all over the place, you got to kind of find the varieties that are more suitable to your conditions. And most of that for the US, most of that relates to just how cold hardy they are. But sometimes, for example, in Florida, it has more to do with their rainfall patterns and their humidity because some varieties do better in high summer rain areas than in more Mediterranean climates like ours. So that's also a challenge.

Farmer Fred:

[57:48] I believe you too also like to use the phrase, all gardening is local.

Greg Alder:

[57:51] Oh, yeah. Even within this little region where I am in Southern California, there are some varieties that do better. I'm 20 miles from the coast as the crow flies. But if I were only two miles from the ocean, i would grow more of one variety than where i am at now 20 miles from the coast just because the sun's more intense here and the nights are colder and so yeah gardening is very very local here.

Farmer Fred:

[58:20]  how pleased are the people that you know who are growing avocados in greenhouses, how happy are they with the taste of the avocado if they can produce in a greenhouse?

Greg Alder:

[58:32] I think they're really happy. At least that's what they say. I'm thinking of a grower in Texas who grows not only avocados, but mangoes and other things as well in a heated greenhouse. He's just absolutely pleased with his fruit. I'm guessing that they taste just as good as mine. I don't know, though. I haven't eaten them, but he's really happy. All right.

Farmer Fred:

[58:59] Right. Now, greenhouses, especially here in central and northern California, where it gets 100 degrees, 115 degrees, the big problem with greenhouses is how the heck can you cool it to remain within a plant's limit? What is the upper limit for an avocado tree?

Greg Alder:

[59:17] So it depends a little bit on some other factors such as humidity and sun intensity and some other things. But what I found at my place in particular is there's really only damage starting at about 103. And then the damage just gets a little bit more intense from there around, let's say, 110. The damage starts to get a little more significant where,  say at 103, you're starting to just get a little bit of yellowing. It's like some sun bleaching on some leaves. And then around 110, you start to get more of shriveling of the new leaves on the tree, sort of like a singeing look. And then up in the 115 range, you start to get damage to the fruit. It doesn't occur right during the heat, but if you're in the 115, 117 range, what you'll find is then, say, a week after the heat is finished, the fruit will start dropping from the tree. Not always all of it, but sometimes all of it.

Farmer Fred:

[1:00:26] It doesn't take much to get a greenhouse up to 115 degrees here in the summertime if the outdoor temperature is 95. It's not uncommon inside my greenhouse. The temperature would be 115, 120. It's better used as a dehydrator in the summertime and just use the greenhouse basically from September, October through May, where you can start plants and keep plants. Otherwise, you're spending a fortune on heating and cooling. And I would think for cooling, it sounds like you'd almost want like a swamp cooler for the greenhouse in order to keep the humidity level a little higher than, say, 10 percent or so.

Greg Alder:

[1:01:01] Yeah, I think if I were in a place where I needed the greenhouse for some extra winter warmth... I would, in the summer, if it were also a hot place in the summer, I would put a lot of shade overhead and make sure that I could roll up the walls very high to get a lot of airflow. Otherwise, yeah, you're just going to cook those little trees.

Farmer Fred:

[1:01:28] Yeah, if you have a plexiglass or a glass greenhouse, you can't roll those up. And yeah, and you need constant ventilation with a temperature-operated fan to keep blowing cooler air in. And the cover, there's all sorts of different levels of shade cloth that you can put over a greenhouse. The key, though,  is if you give it a little bit of room from the top of the greenhouse, build a support on top of the roof of the greenhouse and drape the shade cloth over that, allowing about a 12-inch airspace between the roof of the greenhouse and the shade cloth. It's amazing at how much cooler the greenhouse can be.

Farmer Fred:

[1:02:08] This has been an amazingly varied and informative talk about avocados. This is a pleasure. Greg Alder, gregalder.com is where Yard Post is. Go to his website there, Yardpost. He's a San Diego Master Gardener as well, a director of the California Avocado Society. Greg, I know we left a lot out, but I think we've given enough for a lot of people to figure out if they want to grow avocados or not.

Greg Alder:

[1:02:36] Yeah. You know, we could talk avocados all day, but I think that's a good start. Right. A lot of fun.

Farmer Fred:

[1:02:43] Greg Alder, thanks so much for your time this morning. I appreciate it.

Greg Alder:

[1:02:46] Yeah, you're welcome. Thanks a lot for letting me let me get my avocado thoughts out.

Farmer Fred:

[1:02:52] Garden Basics with Farmer Fred comes out every Friday. It's brought to you by SmartPots and Dave Wilson Nursery. Garden Basics. It's available wherever podcasts are handed out. For more information about the podcast, as well as an accurate transcript, visit our website, GardenBasics.net. And there you can find out about our newsletter, Beyond the Garden Basics. And thank you so much for listening and your support.