Garden Basics with Farmer Fred

214 Your New Friend, the Soldier Fly. Worm Bins. Slow Compost Cure.

July 26, 2022 Fred Hoffman Season 3 Episode 214
Garden Basics with Farmer Fred
214 Your New Friend, the Soldier Fly. Worm Bins. Slow Compost Cure.
Show Notes Transcript Chapter Markers

Garden Basics # 214 Soldier Flies, Improving Slow Compost

If you have a compost pile, or especially a worm bin, you may have seen a scary looking critter: an inch-long wasp-like creature. That’s the soldier fly. But are they good for your compost pile or worm bin? Some gardeners swear by them. Some swear at them. Today, we talk with a big proponent of soldier flies about them, and we delve deep into some of their many benefits. Also, we answer a listener’s question about how to speed up the composting process.

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 we will do it all in under 30 minutes. Let’s go!

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Pictured: Soldier Fly on a Worm Bin
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Napa Co. Master Gardener Penny Pawl:  The Soldier Fly Marches On
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TRANSCRIPTION GB 214 Soldier Flies, Slow Compost

Farmer Fred  0:00  

Garden Basics with Farmer Fred is brought to you by Smart Pots, the original lightweight, long lasting fabric plant container. it's made in the USA. Visit slash Fred for more information and a special discount, that's Welcome to the Garden Basics with Farmer Fred podcast. If you're just a beginning gardener or you want good gardening information, you've come to the right spot. 

Farmer Fred  0:31  

If you have a compost pile, or especially a worm bin, you may have seen a scary looking critter: an inch-long wasp-like creature. That’s the soldier fly. But are they good for your compost pile or worm bin? Some gardeners swear by them. Some swear at them. Today, we talk with a big proponent of soldier flies about them, and we delve deep into some of their many benefits. Also, we answer a listener’s question about how to speed up the composting process.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 we will do it all in under 30 minutes. Let’s go! 

Farmer Fred  1:18  

I remember a few years ago, I went out to the worm bin in the backyard and I took off the lid and all of a sudden this one inch long black Wasp started buzzing and flew away and I'm going, “What the heck was that?” Well, it turns out “what the heck was that” was a soldier fly. And what the heck is a soldier fly? Is it a good guy? Is it a bad guy? Is it the same thing as a soldier beetle? A lot of questions. We have answers from Penny Pawl. She is a Master Gardener over in Napa County here in Northern California. And Penny, you've had adventures discovering soldier flies as well, haven't you?

Penny Pawl  1:55  

Yes, I have. I'm a worm composter from way back before I became a master gardener. And when I first discovered them, they were in one of my worm bins. And I started picking them out and a Bluebellied lizard was between my feet eating them. And that was my first introduction. So then I read online that they were using them  at one of the universities in the Carolinas to compost cow manure in dairies. So from then on, I didn't pick them out. I kept them and I kept some aside to see what they developed into. And it was this black Wasp-looking thing that came right back to my worm bins and start laying eggs. However, I think the snakes, lizards and toads that are living in my worm beds had been eating them. So last spring, I brought some there. It's amazing what people are doing with them now. They are very high protein and they use them to feed their pets, reptiles and chickens and they even have kits for raising them. So you can raise your own soldier fly larva.

Farmer Fred  3:12  

Exactly. We should point out we're talking about for food purposes. The soldier fly larva is very popular among some animal lovers, including those who have, like you said, reptiles.

Penny Pawl  3:24  

And how I happen to write the column was I was at an Easter dinner talking about my compost. And this young man told me about a place in Sonoma that gathers restaurant waste and composts it with soldier flies. And I looked into this place and yes, it does, and it gathers a lot of restaurant waste. That's all they use for composting. They raised the eggs and they also play music for it as they are raising them. I don't know what the music was.

Farmer Fred  4:04  

Now naturally, that's the question I would have right now. By the way, I don't want people to confuse soldier flies with soldier beetles. Soldier flies look like one inch long black wasps. Whereas a soldier beetle, which is a garden good guy, has long segmented antennae and a kind of a red head with with black wings. And the soldier beetle is a pollinator, and they will go after aphids and other plant sucking insects too, especially when they're in the larval stage.

Penny Pawl  4:37  

Right. That's why you have to practice IPM.

Farmer Fred  4:40  

There you go. Integrated Pest Management. That's right. Identify the pest before you do anything. All right, let's talk more about that soldier fly that's in the worm bin. Is it a good guy? Or, is it a bad guy when it's in a worm bin?

Penny Pawl  4:57  

Great guy when it's in a worm bin. I was gone for a couple of weeks on a vacation and when I came home the one bin that had soldier flies had dropped a foot. They're very slow to compost. In fact, I'm harvesting compost from one of them , which is four years old. And I was amazed. I could not believe that had dropped so much. And I get to reading about them. The Internet is a wonderful place to find information on strange subjects. I soon realized that they were very helpful in composting foodstuffs. And manure is good for our garden. There's and sowbugs.

Farmer Fred  5:44  

But are they competing with the worms for the available food in that bin?

Penny Pawl  5:49  

if there are too many of them, they will compete. The advice is not to overpopulate your bin with the soldier fly larva. I did read that soldier fly larva will eat something like two pounds of food a day, which, when you're doing a worm bin, then that's quite a bit. Also, I did read that each female lays about 500 eggs. They only live a week. They fly, they do not eat. During that week, they breed and lay eggs and they drink water. And that's it.

Farmer Fred  6:29  

Now, I too, have read that the soldier fly, if it's in your worm bin in the summertime, because they eat so much, they generate a lot of heat. And in the summertime when temperatures get over 90 degrees that might bring worm work to a near halt in a worm bin. Have you found that to be true?

Penny Pawl  6:47  

 I had a heatwave once where I had one bin and that was in the sun. And the worms were in the middle. I was afraid they were baked. I was gone. I came home, I checked them and the worms were in the middle and they were fine. Another time, I had a flood here and one of my worm bins, and these are large worm bins. And they're not the little ones that you get from a workshop. It starts floating around. I said, oh god, they're go my worms. They were in the middle and they were fine. So they have a way of trying to survive.

Farmer Fred  7:27  

Well, now all of America wants to know about your worm bins. How big are they? Well, what are they?

Penny Pawl  7:33  

Okay, I have eight. Four of them are outside the ground. And they're the Smith and Hawkins type that used to be available. And the other four are buried in the African keyhole method in the garden. And I decided to try that because the African keyhole seemed like a good experiment. And I like to experiment. I want to tell you, those bins do better than the ones above ground. The worms can go in and out. They carry some of their waste with them as they move out. And this year, I planted my tomatoes and my cucumbers around one of the worm bins. They've never been this big. And they've only been in since May 30. I mean, they're huge. It must it must be from being near this active working worm bin and I heartily support. I do teach it for the county and city of Napa. And when I started teaching I had three people and now I have about 25. Very good, amazing the number of people that are doing it.


Farmer Fred  8:56  

 Maybe what you just listened to has piqued your interest in African Keyhole Gardening techniques. The African Keyhole Garden is particularly effective in hot dry climates. It was developed in a hot, dry, poor section of Africa. The keyhole-shaped garden allowed residents to build gardens about six feet in diameter from locally attainable supplies while making the best use of available water. The result: thriving gardens! In Friday’s Beyond The Garden Basics Newsletter and podcast, we continue our chat with Napa County Master Gardener and compost instructor Penny Pawl about African Keyhole Gardening. 

It’s in the next Beyond the Garden Basics newsletter, out Friday, July 29th. Find a link to it in today’s show notes, or visit our website, Garden Basics dot net, where you can sign up to have the free Beyond the Garden Basics newsletter delivered to your inbox each Friday. Also at Garden Basics dot net, you can listen to any of our previous editions of the podcast, as well as read a transcript of the podcast episode you are listening to now. That’s at Garden Basics dot net. For current subscribers, look for the Beyond the Garden Basics newsletter on Friday, July 29th in your email. Take a deeper dive into gardening, with the Beyond the Garden Basics newsletter. And it’s free. Find the link at garden basics dot net. 

GB 214 Soldier Flies, Slow Compost, Part 2

Farmer Fred

 Let's get back to our conversation with Napa County Master Gardener Penny Pawl about worm bins, compost piles and soldier flies. Have you found any foods that the worms just avoid?

Penny Pawl  10:33  

Well, I never put citrus in. Because that changes the pH of the whole system and is not good for them. Otherwise, gosh, they love watermelon. They love lettuce. Bananas. I put in peach pits and they clean them off. They like a lot of fruit. Oh, and one time, I had some tacos in the refrigerator and I didn't like the way they looked. So I threw them in the worm bin. I have never seen such a mass eating frenzy as when they ate those tacos.

Farmer Fred  11:09  

And we're talking about the shells? 

Penny Pawl

You know these were dried tacos. 

Farmer Fred

Oh, okay. Now you have to explain that one. 

Penny Pawl  11:16  

Well, I like to buy in the store in a package. 

Farmer Fred  11:19  

Okay. So tortillas, basically,

Penny Pawl  11:23  

Right tortillas. oh, I'm sorry, not tacos. tortillas. they just went crazy for it.  I put bread in a few times, they like that. The big thing is not to put any meat products in from meat eating animals or cheese or fertilizer from meat eating animals. So I do add chicken manure from time to time to spice it up. I raised butterflies from time to time and I throw their papers and compost into the bin. And it all goes away. Oh, and another thing I put in, it says that you can put in your linen from your dryer, but that has polyester in it. So when I comb my dogs which are long haired dogs, or my hair, I save that and give it to the worms. And when I check the bins, I never find anything like that left over. Usually what I find are a few pieces of wood and labels from apples and tomatoes.

Farmer Fred  12:25  

Indeed. another thing to avoid and worm bins to or oils that you might use.

Penny Pawl  12:29  

Right? Right. They don't like oils. 

Farmer Fred  12:33  

Well, getting back to the African keyhole garden. In that column you wrote you talked about that. Some vegetables do not do well in this type of situation such as tomatoes, potatoes, peppers, eggplant, corn and squash.

Penny Pawl  12:46  

Actually, the only one I don't put in is the citrus because of the pH problem. I never have potatoes to throw in. If I have an old potato, I plant it if it starts getting eyes. As for eggplant, never put that in. I have put carrots in, they always eat them. They're not real particular but they are especially in love with watermelon and cantaloupe. Yes, I put watermelon in. one time oh my god, it was gone in a day. I have one thing that might interest your listeners. is that eight worms, eight, and they have to be red wigglers will produce 1500 babies in six months. So they do breed a lot. And if things are right, their babies grow.

Farmer Fred  13:40  

I would think the conditions are right when you keep your worm bin in an area that is above 40 degrees and below 80 or 85 degrees. They're happy campers.

Penny Pawl  13:51  

My ones out of the ground are in the shade. It's heavy shade, and so they don't heat up. Plus my watering system waters them occasionally. The others are in the sun and I've noticed they heat up and when they heat up the worms go to the bottom.

Farmer Fred  14:08  

Somehow we ended up talking about this when we started talking about soldier flies, but we learned a lot. African keyhole garden,  there's something to explore.

Penny Pawl  14:21  

Right? I really like it. I spoke to one of the beginning classes of the Master Gardeners a few years ago. And the first thing I was asked was how about putting them in the garden and in the ground. So this is not an original idea. other people are thinking about it at all. 

Farmer Fred  14:39  

So for years, I had what I like to call euphemistically a passive compost pile when I had the acreage. And I would take all my yard clippings and just pile it up out in the back 40. And then when I needed a new garden area, I would just move that pile and the soil below it was just excellent for planting,

Penny Pawl  15:01  

 I do the same thing I have a “let it happen” compost pile. And I do use things in the bottom and occasionally I'll go in and collect some wild Worms. Worms have really gone up in price.  when I started it, they were about 50 cents for 50 Worms are now 20 Worms is $2.

Farmer Fred  15:23  

Well, it's good to know though that if the conditions are good, they will reproduce like crazy. So maybe you can get away with, if you're starting a worm bin, you can get away with just buying maybe one pound of worms and then let them procreate.

Penny Pawl  15:37  

one pound is $35. You can order them on line, or I went to the Sonoma worm farm the last time and got three pounds. Those are actively working. And then if I find any wild ones, I I throw them in my bins, and they're usually under pots and rocks, things like that.

Farmer Fred  15:59  

We had a very adventurous little tour with Penny Pawl , Napa County Master Gardener, and we'll have links in today's show notes about African keyhole gardens. More, I'll have the links to Penny’s articles for the Napa County Master Gardeners about the gardens and more about the soldier flies as well. Penny, we learned a lot. Thank you so much.

Penny Pawl  16:21  

Well, you're welcome. I enjoyed it.


Farmer Fred  16:23  

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Farmer Fred  18:23  

We like to answer your garden questions here on the Garden Basics podcast. Amber writes in from Sacramento to Fred at And she says, “I started composting in a black plastic tumbler but it doesn't seem like the material is breaking down, and it looks dry. I've heard that I shouldn't have to add water. But I know that the Sacramento sun is pretty intense. Am I doing something wrong with my compost additions or do I just need to add water?” Amber, the answer is: probably.

Debbie Flower  18:53  

It depends. 

Farmer Fred  18:54  

Yes. Debbie Flower is here. Our favorite retired college horticultural professor who has been basically promoted to America's favorite retired college horticulture professor. Successful compost involves a lot of different elements. You got green, you got brown, you got wet. Yes. And you need all three.

Debbie Flower  19:13  

Yes, you do. The number one thing though, is oxygen. And that's what the tumbler is for, because it allows you to turn the compost easily. I assume. I've never used one frankly, but it takes out the shoveling aspect of it or some of the shoveling aspect of it to turn it. There was a test facility for composting in Tucson, Arizona, which is equally as hot if not hotter than Sacramento, and typically less humid except during the monsoon season. They found that the number one thing they had to do to get successful composting was not add water but turn the compost. However you're using a black plastic tumbler. There are plenty of them on the market.

Farmer Fred  19:55  

 There are, and I used to own a tumbling composter, as well. 

Debbie Flower

Do tell.

Farmer Fred

and I had it in the shade.  And I was more worried about air not being able to get in because it only had the small vents on either end. It was sort of an hourglass shape tumbler. And I tell you, you can get a good workout, just tumbling it when that thing is halfway full to get the other side up. And you had to really push hard on it to get at it. But it was exercise, it was good for you, but still the excess water would flow out these small little vents that were on the bottom. So I just drilled some quarter inch holes on either end, just to give it some more air circulation. And the more often you turn it, the quicker it becomes finished compost. But it did take quite a while.

Debbie Flower  20:49  

So you got some compost out of it. 

Farmer Fred  20:51  

You did get compost, but it was slow. The lack of water could certainly slow down that process if that black tumbler is in the full sun at Amber's place? 

Debbie Flower  20:59  

Yes, definitely it could. Definitely it could. So black plastic heats up very quickly in sun. There's something up against the side of that black plastic inside like media compost, compost with living organisms in it. All the living organisms will die when temperatures get 140 degrees and it only takes a half an hour in that black plastic in the full sun for that to happen. Number one would be move it to the shade, or paint it white, I'd still move it to the shade. At least afternoon shade. Yes, at least afternoon shade. The best compost experiment I ever  participated in was when I taught at a place called the Skill Center, which is an adult vocational school in the Sac City School District. And we were on the old fairgrounds, Sacramento State Fairgrounds on Stockton Boulevard. And there was a brick wall from a building near our classroom. And at the base of it was a concrete pad. So we piled it up, all of the students in that class maintained the landscape. So we chipped, we did chip, made things into smaller pieces, and piled the stuff in the corner. And every day or every two days the students would go outside and I'd have them shovel the pile from one location on the concrete to another location on the concrete. And we did that every day or two days and we had compost in two weeks.

Farmer Fred  22:22  

You make a very good point there about the smaller the pieces are that are added to the bin in this case, the quicker you're gonna get compost. We should explain exactly how does it become compost? what's going on inside there?

Debbie Flower  22:35  

Micro organisms are thriving and consuming what they like which is the brown stuff in the green stuff that's in the compost.

Farmer Fred  22:44  

is this referred to as mychoraezal activity? Not really.

Debbie Flower  22:47  

No. that's because it's not bringing good stuff to a living plant. It's just you might see stuff that looks like fungus growing throughout it, but there's bacteria and fungus and all kinds of other micro organisms working on it at once. And the reason the oxygen is so important is that they do breathe, and they do give off, as humans do, air that's not as good for them as what they're breathing. And if you don't replenish the good air, then they suffocate and die.

Farmer Fred  23:18  

So smaller pieces and plenty of water, Amber. You may want to try sticking a hose in it, add water and making sure water is coming out of the holes at the bottom.

Debbie Flower  23:28  

Well you want it like a wrung out sponge, right? Because you can drown these microorganisms as well. Yeah.

Farmer Fred  23:33  

But still, for a composting bin, a tumbling bin that is going through 100 -110 degree days. Yeah, you're going to need to cool it down. . And that's where the water can come in as long as you've got good drainage and there shouldn't be a problem and you're turning it frequently. With worm bins, It's much the same way. We talked recently with Susan Muckey, who is a master gardener in Sacramento County. She's in charge of the worm bins and composting and she knows what that's all about. And the best way to feed the worms in a worm bin is to grind up the food, maybe dedicate a blender or a food processor. Don't use the good one for your kitchen leftovers and get into smaller pieces, as liquid as possible, and then put it in there. And the same would be true in a tumbling bin as well. Yes, smaller is better, as long as it stays moist, and it doesn't get too hot. And it gets oxygen.

Debbie Flower  24:27  

Since your local, Amber. They do have open days at the Fair Oaks Horticulture Center, which is where the Master Gardeners display both their worm composting and their other composting and so it might be a good place to go and check things out.

Farmer Fred  24:45  

Like on the first Saturday of August, August 6 for 2022. Harvest Day is at the Fair Oaks Horticulture Center in Fair Oaks Park. It's a free event there's free parking and the Fair Oaks Horticulture Center is just a wonderful demonstration garden run by the Sacramento County Master Gardeners, there's perennial plants, there's annuals, there's vegetables, there's an orchard there's a vineyard, there's an herb garden, drought tolerant garden…

Debbie Flower  25:10  

Landscape plants, irrigation, demonstrations, grapes, all kinds of things.

Farmer Fred  25:17  

Yes. If you're thinking of putting in a pond, you can go visit theirs. And of course, the composting area, where they have compost bins and worm bins and different styles, different shapes and you can quiz the composters up there for all your worth on Harvest Day, Saturday, August 6, at the Fair Oaks Horticulture Center, there'll be a link to it in today's show notes, in Fair Oaks Park in Sacramento County. And it's always a nice day on the first Saturday in August. But there's plenty of shade there.

Debbie Flower  25:50  

And there's usually food trucks and water and that kind of thing.

Farmer Fred  25:52  

And speakers, too.  I gotta tell you, it is my favorite garden event, because anybody who knows anything about gardening is there, too, there's all sorts of vendors and speakers and display tables.

Debbie Flower  26:08  

Nursery people.

Farmer Fred  26:11  

yeah, it's great. I like it. Because if somebody comes up to me and asks me a question, I go, “do you see that guy in the floppy hat? He knows more than I do. Go ask him.” Yes.  It works.  All right. So that again, that's Saturday, August 6, Harvest Day at the Fair Oaks Horticulture Center. You'll probably be there. 

Debbie Flower  26:32  


Farmer Fred  26:33  

 Me too. Debbie Flower. Thanks so much. 

Debbie Flower  26:34  

Yeah, you're welcome. 

Debbie Flower  26:38  

Garden Basics With Farmer Fred comes out every Tuesday and Friday and is brought to you by Smart Pots and Dave Wilson Nursery. Garden Basics is available wherever podcasts are handed out. For more information about the podcast, visit our website, GardenBasics dot net. That’s where you can find out about the free, Garden Basics newsletter, Beyond the Basics. And thank you so much for listening. 

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