382 Delayed Winter Pruning of Fruit Trees, and More!

In this episode:

• The benefits of delayed winter pruning of fruit trees, with orchardist and Master Gardener Quentyn Young.

• Controlling ants in raised garden beds, with America’s Favorite Retired College Horticulture Professor, Debbie Flower.

• Protecting your garlic crop in winter weather.

• Redwood tree roots vs. raised garden beds. Guess who wins? How to build up your defenses against tree roots. With Debbie Flower.

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

 Now on YouTube (audio) 

Pictured: The March bloom of the Garden Gold dwarf Peach tree.

Links:

“Beyond the Garden Basics” Newsletter (Mar. 7 edition features Debbie’s recipe for ant bait)

Dave Wilson Nursery https://www.davewilson.com/home-garden/

Ant Control Products

Outdoor Ant Bait Station

Liquid borate for ant control

Fair Oaks Horticulture Center (Sac. Co. Master Gardeners’ Demonstration Garden)

Soil Solarization Tips

Backyard Orchard Culture: Tips for controlling fruit tree height

All About Farmer Fred:
GardenBasics.net

“Beyond the Garden Basics” Newsletter

Farmer Fred website: 
http://farmerfred.com

The Farmer Fred Rant! Blog
http://farmerfredrant.blogspot.com

Facebook:  "Get Growing with Farmer Fred" 

Instagram: farmerfredhoffman
https://www.instagram.com/farmerfredhoffman/

Blue Sky: @farmerfred.bsky.social

Farmer Fred Garden Minute Videos on YouTube
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Chapters

• 0:43 Carrots vs. Ants
• 16:02 Delayed Winter Pruning of Fruit Trees
• 19:09 Dave Wilson Nursery
• 20:28 Q&A Protecting Garlic in the Winter
• 25:16 Q&A Tree Roots vs Raised Beds

Transcript

Ep. 382 TRANSCRIPT  Fruit Tree Pruning, Ants, Garlic, and Tree Roots

Farmer Fred:

[0:06] Hi, it's Master Gardener Fred Hoffman, Farmer Fred, and today we tackle several topics, including the delayed winter pruning of fruit trees, and we answer a variety of garden questions about ant baits, winter garlic care, and tree roots versus raised beds. It's episode number 382, Delayed Winter Pruning of Fruit Trees and More. We're podcasting from Barking Dog Studios here in the beautiful Abutalon jungle in suburban purgatory. It's the Garden Basics with Farmer Fred podcast, brought to you today by Dave Wilson Nursery. Let's go.

ANTS CONTROL TIPS

Amy of NW Florida:

[0:44] Hi, Farmer Fred. This is Amy from Zone 8B in Northwest Florida. I have a question regarding ants in raised beds. I have an ant mound on top of where I have several rows of carrots planted. My carrots have sprouted and I'm wondering, can I use the boric acid sugar mixture where those carrots and the ant mound is and it won’t affect my carrots taste-wise or the yield? What do I do?

Farmer Fred:

[1:23] Amy, thanks for the question from Northwest Florida. And by the way, thanks for listening to the Garden Basics podcast. I appreciate it. Amy, you don't have to worry. That recipe for ant control containing boric acid and sugar, a recipe that Debbie Flower has talked about many times on this podcast, is not going to harm your carrots or your soil because the mixture will be in a container. But you do have to give it a few weeks to do its work because the ants will slowly be taking little nibbles of that boric acid sugar mix back to the ant colony, where it might take a couple of weeks before you cease to see ant activity. Here's how Debbie Flower described it in a previous episode.

Farmer Fred:

 When you go out looking for aphids, you just might see ants crawling up and down the plant where you're finding aphids. What is that relationship between aphids and ants?

Debbie Flower:

[2:15] Yeah, ants collect that honeydew and eat it. They like that honeydew. Because they like it so much, they will actually protect the aphids from those beneficial insects like the lady beetle larva and the lacewing larva and a myriad of other beneficials that will eat the aphids themselves. And there are videos, there's probably YouTubes, where you can look at where people have photographed the ants actually chasing off lady beetle adults who want to lay their eggs among the aphids and other beneficial adults so that they can take care of the aphids, protect them from the beneficial so they don't get eaten. They'll also move the aphids around when the population of aphids gets crowded. The aphids themselves will produce a population that have wings so that they can go to a different place that isn't so crowded. But the ants will help that along. They'll move the non-winged aphids from place to place so that they have a bigger population from which they can collect the honeydew. So ants are basically farming the aphids and protecting the aphids from their enemies.

Farmer Fred:

[3:21] Nature's little ranchers. Yes. Those ants are harvesting that honeydew. So, we've attempted to control the aphids. Now we need to control the ants. What is the most effective way to control ants? Ants are tricky.

Debbie Flower:

[3:37] They're very well organized as a society, and they have lots of workers that are out there. And the best way to control the ants is to kill the queen in the colony. But that's tricky. She doesn't come out. She's the one who's laying all the eggs and all her minions are taking care of those babies and bringing food into the colony and protecting the colony from anything that might hurt it. But she doesn't come out. And so we have to get to her by her workers. The ones who are out collecting food are the ones that are going to take food to the queen and feed her. And so we don't want to necessarily kill them where they are. We want them to take something back to the queen and kill her. Once that happens, the colony falls apart.

Farmer Fred:

[4:22] Yay! But I would think that just like in plant life and fertilizers, a little bit of something that kills ants goes a long way. Whereas if you put too much of the bait out for them to take back, they recognize it as not good and will walk around it.

Debbie Flower:

[4:40] Either that or they will eat it themselves and die before they get back to their queen.

Farmer Fred:

[4:44] Ah, and you don't want that.

Debbie Flower:

[4:45] Right. The queen is constantly producing new babies, and so there's always somebody waiting to take that guy's job. Sounds like some bosses I've had.

Farmer Fred:

[4:56] So the control that we're hedging about is boric acid, but it goes by several names on some ant bait control products. It might say orthoboric acid or something with the word borate in it.

Debbie Flower:

[5:10] Borate, right. Yeah. Yeah. There's several words, but look for that bore part. Yeah.

Farmer Fred:

[5:14] And it comes in many styles. There's a powder, a dust available. One popular brand that's pure boric acid is called Roach Pruf. And there are the little bait stations you can buy. They're usually sold in four packs or six packs and you just put that along the ant trail and they will go in there. You know, the problem with those I have noticed in using them indoors to control Argentine ants is they tend to die right there and you wonder how much actually makes it back to the nest. Whereas with boric acid, the powder, they just get it all over them and take it back to the queen.

Debbie Flower:

[5:53] I have not had the same problem with the prepackaged traps. I had a bunch of ants living in some of the plants in my greenhouse. And when I watered the plant, the ants came out and they just swarmed the top of the plant. And so I just put one of those little baits and they do come in different. There are some specifically for outdoors and some specifically for indoors and some where you can use in either indoors or outdoors. And I had one, it was like a tube of pre-mixed liquid ant bait and I put it in the greenhouse and I put a broken piece of ceramic pot over the top so that it wouldn't get wet and pretty soon, and I put one on the greenhouse bench, one outside the greenhouse where I saw the trail of ants coming in and one in the pot itself and the ants disappeared completely. So I've had, and I used it in my bathroom as well. Well, they seem to love the bathroom for some reason. I have a lot of plants in there, too. Well, that's why. That may be it. Yeah. And it leaked all over the floor. So the type of trap may be of interest to you. They may work in different situations.

Farmer Fred:

[7:06] There are other ant bait stations, too, that are refillable. You would fill them with a liquid ant control product that has boric acid in it that's usually diluted with water. And these are reusable stations. They're kind of nice. You can stick them in the ground or place them outside. And once the liquid is gone, you can just refill it with the proper formulation. And you have to be patient with this. Unlike the sprays where you see immediately kill of ants, which, as we pointed out, could also kill the good guys, the liquid products we're talking about tend to work more slowly. And it might take a week or two. And this goes with the boric acid powder as well. It might take a week or two for you to control that invasion of ants.

Debbie Flower:

[7:49] Right. And you might be very surprised and perplexed that there are more ants around at first than when you put the bait out. And that's because they found this wonderful, easy source of something to eat. To them, it's sweet and tasty and wonderful food. And so they come and they call their friends and their friends come and everybody's feeding like pigs at a trough around this ant bait. But just let it be. And as you say, it takes time. they have to take it back bit by bit to their queen and then get enough. She's quite a bit bigger than they are twice or maybe three times the size that they are. So it will take quite a bit to kill her, but she has to be fed it over a period of time. And that's where those weeks come in.

Farmer Fred:

[8:31] But you being a gourmet cook and a gourmand have a homemade concoction for ant control.

Debbie Flower:

[8:38] Right. Not something I would eat, although it is not toxic to me. And that's the wonderful thing about these boric acid baits, boric acid, borate, orthoborate. Read the active ingredients list on the package. By law, it has to be there. If it has that in it and only that, besides things like sugar and water, it is not toxic to humans or birds or bees or fish or your dog or cat. So it's not something to stress about in the quantity in those containers that they will not harm mammals.

Farmer Fred:

[9:16] Is it harmful to beneficial insects?

Debbie Flower:

[9:18] Not that I'm aware of.

Farmer Fred:

[9:19] Yeah, me neither. I'm not sure of that. It's sort of like the chemicals that are registered for use on aphids, like insecticidal soap or some sort of lightweight horticultural oils. They only harm the beneficials if they are hit directly by the soap or the oil. 

Debbie Flower:

[9:37] Correct. But they'll only harm the aphids if they are hit directly by the soap or the oil as well.

Farmer Fred:

[9:43] There's no residual action on those.

Debbie Flower:

[9:46] Right. And the boric acid is the same. It has to be consumed. So it's presented in those baits, in those traps, in a way that is really set up for ants to find it and easily access it. So the size of the opening, the position of the opening, those sorts of things are created with the ants in mind. And other insects don't quite fit. When I spilled it in my bathroom, nobody else showed up. But it's my bathroom. I was happy about that.

Farmer Fred:

[10:15] Well, we've given people enough time to find pencil and paper to jot down the Debbie Flower Recipe for Controlling Ants.

Debbie Flower:

[10:23] It's a really simple recipe. It is nine parts of sugar and one part of boric acid.

Farmer Fred:

[10:31] So like one teaspoon and nine or ten teaspoons. Right. Okay. One teaspoon of boric acid.

Debbie Flower:

[10:37] Yeah. And don't put extra boric acid in it. Boric acid is sold as a one brand is called roach pruf. There are others. They tend to be in squeeze bottles, round squeeze bottles, because roaches tend to be in walls and and small spaces where you have to put in the nozzle and squeeze in the boric acid. And professionals do use boric acid for roach control. If you're having a roach problem, you can ask your professional if that's what they're going to use. And it just dries them out. It just dries their bodies out and they shrivel up and die. But we don't want, as we've said, we don't want the ant to shrivel up and die. As soon as it eats it, we want the ant to take it back to the nest and feed it to the queen. So we're going for a very low concentration of boric acid in this mix.

Farmer Fred:

[11:26] And in this case so far, we have one part boric acid, nine or 10 parts sugar. And then when you mix it together, I guess you want to make a slurry with some water?

Debbie Flower:

[11:34] Right. So you make the slurry and how thick that slurry is depends on how you're going to apply it. If it's on my kitchen counter, I'll put out a piece of wax paper or aluminum foil and I'll make the slurry thinner than toothpaste. I want it to stay on the piece of paper but not dry out immediately. It does dry out fairly quickly.

Farmer Fred:

[11:54] Cottage cheese.

Debbie Flower:

[11:55] Have you put it in cottage cheese?

Farmer Fred:

[11:57] No, I'm just wondering if it has the consistency of cottage cheese.

Debbie Flower:

[12:00] Well, is it big curd cottage cheese or small curd?

Farmer Fred:

[12:02] Well, it would be small curd cottage cheese. And it would be the creamy cottage cheese.

Debbie Flower:

[12:07] Creamy cottage cheese, yes. Something that will stay on the aluminum foil or wax paper. Put it in their pathway. At first, they spend time checking it out, checking out the paper I've put it on, etc. And eventually, somebody will start eating it, and then they'll all show up and feed on that. If I'm putting it outdoors, then I will put it in a container, maybe a yogurt container, something with a lid that can be put back on.

Debbie Flower:

[12:35] And I put cotton balls in that container. Dig a little hole around the base of the plant so that the container will fit in the hole and the lid will be at soil surface. And then put little ant-sized holes in the lid. And pour the slurry. In this case, I'd probably make it wetter, looser, so that it would be absorbed into the cotton balls. And the cotton balls, the purpose of the cotton balls is that the ants have something to sit on while they're feeding. And so you want the cotton balls to basically fill up the container, pour the now thinner, maybe even as thin as juice, slurry over the top, put the lid on, put it in the hole, and walk away. And the ants, you want the soil right up against the container. So the ants have a nice, easy way to get to the top of that container. And they will go in or they may feed from the hole, depending on how close the cotton balls are to the top. And they will collect the bait from there, take it back and come back and feed again. The lid helps it from drying out. It helps keep stuff you don't want like leaves and mulch and soil from getting into the bait and gives the ants a way to get in and out.

Farmer Fred:

[13:46] All right.

Debbie Flower:

[13:47] The paste will dry out. And so you have to replace it periodically. So I make a whole bunch of it, put it in a jar or some kind of container, keep it around. You can check it periodically, add a little water if it's starting to dry out, and then check my baits and go bait stations and replace. In the kitchen, I'll just throw out what I used one day and put some new.  Outdoors, you can empty the cotton balls and redo it, or you can just top it off.

Farmer Fred:

[14:13] So I'm looking at my ruler here to determine what size these holes should be for ants. And if I'm an ant in a social situation, I think a two-way street would be best for the ants going in and the ants coming out. So probably twice as wide as the body of an ant. And ballparking it, I would probably say, well, not a quarter inch, probably an eighth of an inch. So for those of you that like exact measurements, use your one-eighth inch drill bit to make the holes.

Debbie Flower:

[14:46] Or you can pound it with nails, find a board, put the lid on the board and hammer a nail through and pull it out. A nail, pull it out to make the holes. Or a knife. Knife is a little harder because it leaves those sharp edges. It's hard to get the material out of the lid. You end up with just an opening, but the end has to push its way through. So something like a nail or a drill bit would make the best holes in the top of the lid.

Farmer Fred:

[15:12] Or for real fun, a BB gun.

Debbie Flower:

[15:16] I suppose you could. Yeah. Target practice.

Farmer Fred:

[15:19] For those of you in the country. All right.

Debbie Flower:

[15:20] Get the kids outside.

Farmer Fred:

[15:22] All right. Another reason for the lid, too, is I guess would be to keep dirt and pets away.

Debbie Flower:

[15:25] Keep them out of it. Absolutely. Right. Yes. Anything else out of it.

Farmer Fred:

[15:29] All right. And by the way, we'll have this link that includes Debbie's recipe also in today's show notes about how you can make your own boric acid bait trap. And again, it would be like in a tuna can or a cat food can outdoors with a lid on one of those plastic lids. So say goodbye to that plastic lid.

Debbie Flower:

[15:48] Right.

Farmer Fred:

[15:48] Yes. All right. That would work.

Debbie Flower:

[15:50] And those lids are for tuna cans and cat food cans are readily available at your local grocery store.

Farmer Fred:

[15:55] You want to control ants? There's a lot of good tips for you. Debbie Flower, thanks for all the great advice.

Debbie Flower:

[16:00] My pleasure. Thank you.

DELAYED WINTER PRUNING OF FRUIT TREES

Farmer Fred:

[16:02] We're at the Fair Oaks Horticulture Center. It's a workday Saturday here in February, and we are talking to orchard specialist and Master Gardener Quentyn Young. Q, it's wintertime, but a lot of us preach the value of summer pruning of deciduous fruit trees, and there's a lot of good reasons for that. But people may be wandering around their fruit trees and saying, I don't like that branch there. It's too long, or that one's rubbing, or that one's crossing through the tree, cutting air circulation. Can I cut it now or should I wait for warmer weather before I do that?

Quentyn Young:

[16:35] So what we usually recommend is you wait until probably March or April. We call it delayed winter pruning. And that's kind of our segue into what we call summer pruning. But we tend to advise people try to do as little pruning as possible.  And I mean, obviously, if it's a hazard, if it's a broken branch or something like that, you could take that off. Definitely. Sometimes you have to. But what I've been doing for most branches right now is marking them with tape to do a cut later. 

Farmer Fred:

Two trees in particular are very sensitive to pruning in the wintertime, and that would be apricots and cherries. Why is that? 

Quentyn Young:

Both of them are susceptible to eutypa and a lot of other bacterial infections. We have such a rainy winter, which is great, but it also brings its own host of problems. So you just want to delay pruning those guys either until spring or if you're going to do it, let's say in the summer, no later than October.

Farmer Fred:

[17:26] All right. And the value of summer pruning is what?

Quentyn Young:

[17:30] If you come to the orchard, you'll see we keep all of our fruit trees basically in the six to eight foot range. It's really easy to do that, throughout the summer, by regular pruning. It makes it easier to harvest. You can get more trees into a smaller space. They're just much easier to maintain that way.

Farmer Fred:

[17:47] And finally, a little recipe for you. If anybody at home has citrus trees, you know how they tend to all produce at once and they're already at once? What do you do with them? And on two of my citrus trees, it was a Morro blood orange and a Gold Nugget mandarin. They were both full, and they both needed to get harvested. We made juice by combining the both. The Morro blood orange tends to be a little bit, I won't say sour, but it's tart.

Quentyn Young:

[18:16] Yeah, it's got a nice berry aftertaste.

Farmer Fred:

[18:18] But you mix that with mandarin, it was like a 30% of the Gold nugget Mandarin juice and 70% of the blood orange juice. And it's fantastic.

Quentyn Young:

[18:26] Yeah, it's a great mix. In fact, when I was in Sicily, that's what they were doing. The fresh juice sellers were doing a blood orange, regular orange, pomegranate combo. And it was a really good combination of flavors.

Farmer Fred:

[18:39] And it's pretty easy to preserve too, because obviously you're not going to drink it all at once. And what we were doing is putting them in heavy-duty canning jars, one-quart canning jars, and sticking those in the freezer.

Quentyn Young:

[18:49] Yeah, or even a lot of people fill up an ice cube tray, freeze them, pop up with ice cubes, put them in a bag, and put them in the freezer. Now you're good to go.

Farmer Fred:

[18:57] Like the old saying goes, if life hands you a lemon, make lemonade. Make lemonade or make frozen lemonade and save it for later. All right. Now, if only I had a pomegranate tree to try that recipe. There you go. Thanks, Q.

Quentyn Young:

[19:08] Thank you.

DAVE WILSON NURSERY

Farmer Fred:

[19:11] You have a small yard and you think you don't have the room for fruit trees? Well, maybe you better think again. Because Dave Wilson Nursery wants to show you how to grow great tasting fruits like peaches, apples, pluots, and nut trees. Plus, they have potted fruits such as blueberries, blackberries, raspberries, boysenberries, figs, grapes, hops, kiwi, olives, and pomegranates. These are all plants that you can grow in small areas. You can even grow many of them in containers on patios as well. It's called Backyard Orchard Culture, and you can get step-by-step information via the Dave Wilson YouTube videos. So where do you find those? Well, just go to DaveWilson.com, click on the Home Garden tab at the top of the page. Also in that Home Garden tab, you're going to find a link to their fruit and net harvest chart. You can be picking delicious, healthy fruits from your own yard from May to December here in USDA Zone 9. And something else you're going to find in that home garden tab. You're going to find the closest nursery to you that carries Dave Wilson's quality fruit trees, and they're in nurseries from coast to coast. So start the backyard orchard of your dreams at DaveWilson.com.

WINTER GARLIC CARE

Farmer Fred:

[20:30] We get a question from Paul. He lives in southwestern Pennsylvania, USDA Gardening Zone No. 6. And he says, “I planted garlic on October 16th last fall. And as the Indian summer moved in, I couldn't keep the sprouts from popping up through. So in an effort to protect the sprouts and delay what ended up being the inevitable, I mulched heavily with shredded leaves and compost. Still, the sprouts persisted and came through. Then they were under many inches of snow for extended periods. My question is, with the state of the leaves now being green and wilted and laying flat on top of the mulch, what do you think I can expect in spring? Will the existing green sprouts of garlic die, and then will new ones come up? Will it rob the bulb of energy forming a new leaf set? I thoroughly enjoy all the solid horticultural information I receive from your podcast, and anxiously await your new episodes. Thank you for all your work. By the way, the garlic varieties I planted include Music, Chesnock Red, and Georgian Fire. Thank you.”

Farmer Fred:

[21:32] Hey, Paul, I think you're off to a great start. But keep covering those green shoots with more shredded leaves or straw, or even a frost cloth to help prevent future damage from a late winter or early spring freeze. The varieties you're growing are all hardneck varieties, and those can take cold temperatures down to 30 below zero. I hope you don't have those kind of temperatures there. Peaceful Valley Farm Supply Company, a great catalog for organic gardeners, offers this advice about winter protection for your garlic. They, too, talk about the benefits of mulching. They say mulching is essential for winter protection when planting garlic, offering multiple benefits for the health and growth of your garlic crop. A thick layer of organic mulch, such as straw or shredded leaves, helps insulate the garden bed and protect the garlic cloves from severe cold temperatures. This layer maintains consistent soil temperature, it prevents the ground from freezing, and supports garlic plants in growing strong roots through the winter. Additionally, mulching with materials like straw or shredded leaves reduces moisture loss and can help suppress weeds, contributing to better bulb formation, as well as larger garlic bulbs come harvest time. So proper mulching ensures your garlic is well protected, it promotes healthy growth, and you'll get a successful garlic crop in the spring. They go into more detail about the varieties of mulch you could use. They say for garlic, use organic mulch types like straw, shredded leaves, or wood chips. Those all can be highly effective. Straw mulch is popular because it offers excellent insulation against cold temperatures and helps maintain soil moisture.

Farmer Fred:

[23:12] Shredded leaves also create a thick layer that shields garlic plants from frost and prevents the ground from freezing. Wood chips or chopped bark can be used in raised beds in traditional garlic beds to support root growth and enhance soil fertility. Choosing the right mulch. That helps your garlic cloves over winter successfully, ensuring robust growth and a bountiful harvest in the spring. But they do point out that to effectively mulch for winter protection, it's important to follow proper mulching techniques to ensure your garlic thrives. Begin by applying that thick layer of mulch, and that layer will help to insulate the soil and protect garlic bulbs from freezing temperatures. For best results, spread the mulch after the ground has frozen, but before extreme winter temperatures set in.

Farmer Fred:

[23:58] Make sure the mulch is distributed evenly around garlic plants to maintain consistent soil temperature and moisture, promoting healthy root growth, and preparing your garlic cloves for a successful spring harvest. They also point out it's important to manage the watering needs of the garlic during winter dormancy. Garlic plants, whether hardneck garlic or softneck garlic generally require minimal water as they're in a dormant state, but you must ensure that the soil remains well-drained and does not become waterlogged, which can lead to root rot. While the ground freezes and cold winter temperatures prevail, it's important to avoid over-watering. Instead, check soil moisture occasionally to keep it slightly moist but not soggy. Paul, once again, thank you for the question. Good question, and I hope you have a lot of success with your garlic this coming spring and summer.

TREE ROOTS VERSUS RAISED BEDS (originally aired in Ep. 77)

Farmer Fred:

[25:25] We like to answer your questions here on the Garden Basics podcast. There are several ways to get in touch with us. You can always email in your question with pictures. The email address, fred at farmerfred.com. Or you could even leave an audio question without making a phone call. Do it via SpeakPipe. That's speakpipe.com. It's easy. Give it a try. And you just might hear your voice on the Garden Basics podcast. And of course, you can even phone or text us with your questions or pictures at 916-292-8964. 916-292-8964. And don't forget to tell us where you're from. That'll help us greatly to accurately answer your garden questions. Because as I'm fond of saying, all gardening is local. And when we answer your gardening questions, we bring in the big guns, retired horticulture professor, Debbie Flower.

Farmer Fred:

[26:28] Jim writes in, and he's building some raised beds, and he says, I'm in the process of building two new four-by-eight-foot raised beds. The height of the raised beds will be about two-and-a-half feet tall. My concern is the adjacent redwood trees in my neighbor's property. Their roots would like nothing better than to get into my new raised beds. I know this because they've already gotten into my other raised beds. I have several solutions, I think, but would like your opinion on the one to use. One is to put down a layer of landscape fabric. Second is to put down a 4x8 sheet of quarter-inch plastic. The third idea would be to use some half-inch mesh wire hardware cloth. And the fourth idea is to use some metal flashing that is used for roofing. Well, at least you gave yourself a lot of options, Jim, on that one. Yeah, he's been thinking about that. But we have a problem here, and that is the fact that, yeah, you do want to stop the tree roots, but you also don't want to stop the flow of air and water at the base of the raised bed. You want to be able for that, especially the water, to percolate into the soil below, and then that way you won't have a permanent puddle of water at the bottom of the raised bed.

Debbie Flower:

[27:45] Right. You want the raised bed open at the bottom so that the plants in the raised bed don't die from too much water.

Farmer Fred:

[27:51] So how do you get around that? What do you do? And first, oh, by the way, folks, for those of you listening back east and are thinking, “Redwood trees, I've seen those trees in California. They're big. Why would somebody have those in their backyard?” And you know, that's a very good question. I don't know why.

Debbie Flower:

[28:07] Yes, they're fast growers and they make great view blockers, but after a certain age or size, they take over. Then they tend to throw second leaders and those leaders get bigger and fatter with time. And a friend of mine had one break in a rainstorm and go right through his roof into the bedroom, and out the window of the bedroom. It took six months to get that whole roof replaced and all the damage fixed. Its number one rule is pick a plant that fits the size that you have to give it.

Farmer Fred:

[28:40] If I was mayor of suburbia, I would make a rule that no backyard tree could be larger than 35 feet. I probably wouldn't get reelected, but I would make that rule. Yeah.

Debbie Flower:

[28:51] Yes, there are places, there are gated communities in this part of the world that make rules like that. And it's mostly for views so that you can get some shade, but your neighbor can see the lovely mountain views nearby. So there are places that would accept that advice, but other people would not.

Farmer Fred:

[29:06] Yes, exactly. And another thing, too, is for solar panels. And here in California, there's been a lot of legislation to make it easier to install solar panels. And one of those rules includes your neighbor can't block your sun.

Debbie Flower:

[29:20] Right. And you don't want to block your sun yourself.

Farmer Fred:

[29:22] Exactly. Yeah. So think about that. Anyway, we got Jim with his hardware cloth, with plastic, with the sheet metal flashing used for roofing or landscape fabric.

Debbie Flower:

[29:38] Number one thing to think about is that he cannot keep the roots out. Roots have an ability, they grow a certain depth below the surface of the soil. And that depth is determined by the amount of oxygen available in the soil. If you layer things on top of the soil, he's going to about two and a half feet. Then the oxygen can't penetrate what used to be the surface. And so the roots will move up into the top of that bed. It'll take a while. It won't be tomorrow. But he is going to have a root problem with that plant. And he has it with his other beds. Number two is you can't stop them from growing in that area. If it were my bed, the first thing I do is dig down a little bit around where that 4x8 raised bed is going to be. And with loppers, with sharp tools, cut off any roots that are currently underneath the area where the raised bed will go. It will not harm the tree if you make nice, clean cuts.  The tree will make roots in other places. It'll first rely on the roots it has, and then it will make roots in other places where it can grow.

Farmer Fred:

[30:52] And I think any person, any gardener, who has dealt with tree roots invading their garden, know it isn't just redwood trees that are culprits. There are many, many tree varieties that have invasive root systems.

Debbie Flower:

[31:05] Yes, the tree that comes to mind for me is a fruiting mulberry. My last house had a terraced garden, and I went outside on the patio, went down two steps, and then I was on the lawn, and then I went down, and the vegetable garden was on the lawn level. And then I went down about eight steps, and I was on the lower level, and then there was a level below that. The mulberry was on the, after the eight steps, that lower level, and my vegetable garden was the level above that. And eventually, when I went to dig in my vegetable garden, the mulberry roots were there. And I knew there were mulberry roots because they have a distinctive color. That's when the mulberry tree got taken out. So, yeah, trees have problems in vegetable gardens.

Farmer Fred:

[31:48] How far was that vegetable garden from the trunk of the mulberry tree?

Debbie Flower:

[31:52] At least, I'd say, 20 feet.

Farmer Fred:

[31:55] Yeah, tree roots go a long way. They go beyond the canopy of the tree.

Debbie Flower:

[32:00] Very far beyond the canopy of the tree. And they end up in places that have the things that they want, which is water and nutrients and oxygen. And of course, my vegetable garden had those things and the lawn nearby had those things. I never dug up the lawn, so I don't know if the mulberry roots were under that as well. But they did get into the vegetable garden.

Farmer Fred:

[32:20] Jim also mentions in his email the fact that he's putting these raised beds on what is currently lawn. And that brings up another issue as far as, well, a lot of people will just build a raised bed on top of a lawn and think nothing of it. I tell you, if you're doing it on Bermuda grass, the Bermuda grass will find its way to the top. And I would definitely want to remove some of that turf, if not all of it.

Debbie Flower:

[32:46] Yes, I would maybe take a season out and solarize it. Solarization is a way of sterilizing the soil, so killing everything in it. But it has to be done with the heat of the summer. And so you would miss this season's growing of vegetables like tomatoes and peppers. You have to prep the soil, scrape the stuff off the top, the lawn, off the top and the weeds. Prep the soil by turning it, water the soil, and then use very thin plastic and bury the edges and leave it for six to eight weeks.

Farmer Fred:

[33:18] Clear plastic.

Debbie Flower:

[33:19] Clear plastic, yes. And very thin plastic. and the plastic I used was the drop cloth plastic you can buy in the paint department of a big box store. The thinnest stuff you can get.

Farmer Fred:

[33:30] I think two to four mil is the thinnest.

Debbie Flower:

[33:32]  You can even use dry cleaning plastic, but that would be a nightmare getting it all spread out and making sure you have no holes in it. You must bury the edges because you must trap the heat from the sun that comes through the plastic and hits the soil. The light of the sun becomes heat and it heats up the soil and it'll go three, four, five, six inches. It depends on your soil texture that five, six, you'd have to have a very sandy soil, inches deep and kill everything in that area. And I did it for nutsedge, which can be a terrible weed. And it worked for the time that I lived on that property. Eventually, of course, everything moves back in, Bermudagrass being one of the worst. But you can try to get it out at least for a few years.

Farmer Fred:

[34:17] Exactly. Farmer Fred Garden Rule Number One, “Bermuda grass is forever”.

Debbie Flower:

[34:21] Yes, I think of you often as I work in my yard.

Farmer Fred:

[34:24] Now, however, I did that same thing. I did soil solarization one summer on an area that was Bermuda grass and converted it into a citrus orchard. And I was not bothered by Bermuda grass for the remaining 10 years we lived there.

Debbie Flower:

[34:41] Yeah, it's a very powerful way to to get your soil ready. Solarized, it would also kill the roots that are in that area, the roots of the trees nearby that are going to cause potential problems.

Farmer Fred:

[34:55] There are a lot of important steps, though, in soil solarization that we don't have time to go for in here. But in today's show notes, I will provide you some links on the complete step-by-step of effective soil solarization And that can really do a great job of controlling existing grass and rhizomes, existing nematode issues, pest problems, seeds that you don't want of whatever. It's very effective, especially if the soil is moist before you cover it. And it can kill, I think, roots and seeds down about 8 to 12 inches as long as you keep it covered and allow that temperature to get up to 120, 140 degrees.

Debbie Flower:

[35:37] Yeah, it's a temperature process, yes.

Farmer Fred:

[35:41] And none of this answers Jim's questions, but the fact of the matter is when you're building a raised bed, before you pound your first nail or put your first screw in those boards, think about the existing soil and what's already there. And let's go back to what we were talking about at the beginning. If you want air and water flow to go through that raised bed and not puddle at the bottom, you’ve got to make sure that that soil level below has somehow been incorporated with the new soil that you're bringing in. And it doesn't have to be deep. It doesn't even have to be rototilled in. If you just take a spading fork, loosen up the existing soil, put down an inch or two of the new soil, that might be enough.

Debbie Flower:

[36:25] Yes, whatever you're putting on top. Many people use bagged media or they get it in bulk from a soil supply place that has a lot of organic matter in it. And it's different, has way more organic matter in it, whether you're using bagged soil or you're buying a mix from a supply place. It has much more organic matter in it than your field soil does, just by definition. It's just unless you live in a delta, a river delta.

Debbie Flower:

[36:52] The water travels the path of least resistance and it will go down through your very nice, very organic soil that's in your raised bed. And when it reaches the field soil that is much more mineral, much less organic matter, it will stop and it will build up until there's so much water in the bed that the next drop actually pushes the water out. And then you'll get water on the surface of the soil around the raised bed. A better solution, better for your plants, too, because it provides a deeper root system and you don't go through this saturation period, is to take some of the new stuff, whatever that is, the bag material or the stuff you bought in bulk, and lay about a two-inch layer on top. Use a tool. A spading fork is definitely a good one. Turn it in to about two more inches. So you've got about a four-inch transition zone that is a 50-50 mix of your new soil that you're going to put in your raised bed and your existing soil, which is your landscape. Then the water will not build up, stop at that layer and build up in your raised bed. It will drain deep into the soil below, and your roots will have the opportunity to grow down there. It helps things like tomatoes.

Farmer Fred:

[38:02] So, Jim, in a nutshell, what we're trying to tell you is cut the roots out.

Debbie Flower:

[38:06] Yeah. And I would not use plastic under that raised bed because it's going to stop water, even if you put some holes in it. And eventually it breaks down and then you've got all these plastic shreds in your soil. And it's a mess.

Farmer Fred:

[38:21] Yeah, landscape fabric isn't much better than plastic either. It can be very messy. And I would think, too, that even the pores in landscape fabric buried at that level would eventually clog. 

Debbie Flower:

[38:33] Yes. And roots will grow right into it. They love it. They love it. They find it very accommodating. It does not keep weeds out. It actually helps them anchor into the landscape. So roots coming up from the bottom could do the same thing. So those two are out. I didn't even understand, excuse me, the metal flashing one. All I pictured was metal going straight down the sides of the bed, which just just deepens where the roots would go anyway.

Farmer Fred:

[38:59] I mean, I think that can be a short term solution. And the fact it would probably be good for five or 10 years. But I mean, that's what they would do to control, say, running bamboo would be to put down big sheets of some sort of galvanized metal, maybe as deep as 36 inches and surrounding the plant to keep it from doing that. So I guess you could do that as well, except I think where Jim lives. It's fairly rocky soil. So good luck with that.

Debbie Flower:

[39:29] Right, that's going to be a lot of work. And you want ideally zero seams. That's not going to be possible. You're going to have one seam somewhere at least. You might have more where roots, because roots will get into those seams and start to grow. So yes, if you went deep, it would keep the redwood tree roots from getting under the bed. So that is a possibility. And you could use that with or just by itself use the mesh of metal. Critters live in soil. Moles live in soil. Gophers live in soil. And they can come up underneath your bed and do damage from underneath. And so if you use, if you line the base of your wood four by eight raised bed with mesh material, but it needs to be, the word escapes me.

Farmer Fred:

[40:18] No, it's pretty good heavy gauge stuff. half inch hardware cloth.

Debbie Flower:

[40:22] Right. Galvanized, right? Right. Yes. So it needs to be galvanized hardware cloth that you would probably staple to the inside of the wood and have a continuous come up the sides a ways so that these critters that live in the soil cannot get into the roots of your plants and water and air can travel freely from your bed into the field soil.

Farmer Fred:

[40:45] That will do a good job stopping gophers and moles if you want to stop rats, squirrels, skunks, raccoons. Good luck.

Debbie Flower:

[40:54] Yeah, really.

Farmer Fred:

[40:56]  So basically, Jim, yeah, you're going to have to cut the tree roots or pay your neighbor to take that tree out.  Good luck with that one.  Well, it's a thought. Good luck, Jim. All right. Once again, we have gone to the root of the matter. And with that pun, thank you, Debbie Flower, for your help on our little question and answer.

Debbie Flower:

[41:16] You're welcome, Fred.

Farmer Fred:

[41:23] Garden Basics with Farmer Fred comes out every Friday and it's brought to you by Dave Wilson Nursery. Garden Basics is available wherever podcasts are handed out. For more information about the podcast, as well as an accurate transcript of the podcast, visit our website gardenbasics.net. And thank you so much for listening and your support.