326 Q&A Working with Coir vs Peat Moss, Reuse Old Potting Soil. Runaway Plum Tree!

Garden Basics with Farmer Fred

Tips for beginning and experienced gardeners. New, 30-minute (or less) episodes arrive every Tuesday and Friday. Fred Hoffman has been a U.C. Certifi...

Show Notes

Q&A - Working with Coir, Peat Moss, Perlite, etc. Reusing Old Potting Soil. 00:24
Q&A - Runaway Plum Tree! 16:10

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.

Pictured: Wheelbarrow with Homemade Potting Mix

 Subscribe to the free, Beyond the Garden Basics Newsletter https://gardenbasics.substack.com
Smart Pots https://smartpots.com/fred/
Dave Wilson Nursery https://www.davewilson.com/home-garden/

Peat Moss
Drip Irrigation Micro Sprayers

Got a garden question? 

• Leave an audio question without making a phone call via Speakpipe, at https://www.speakpipe.com/gardenbasics

• Call or text us the question: 916-292-8964. 

• Fill out the contact box at GardenBasics.net

• E-mail: fred@farmerfred.com 

All About Farmer Fred:
The GardenBasics.net website

The Garden Basics with Farmer Fred Newsletter, Beyond the Basics

Farmer Fred website

The Farmer Fred Rant! Blog

Facebook:  "Get Growing with Farmer Fred" 

Instagram: farmerfredhoffman

Twitter/X: @farmerfred

Farmer Fred Garden Minute Videos on YouTube 

 As an Amazon Associate, I earn from qualifying purchases from possible links mentioned here.

Thank you for listening, subscribing and commenting on the Garden Basics with Farmer Fred podcast and the Beyond the Garden Basics Newsletter.

Show Transcript

GB 326 TRANSCRIPT Q&A Coir, Peat Moss, Reusing Potting Soil


Farmer Fred  0:05  

Welcome back to the Tuesday edition of the Garden Basics with Farmer Fred podcast. Unlike the Friday edition, we're dedicating the Tuesday podcast to answering your garden questions. Stay tuned to find out how you can get your garden questions into the program. So come on, let's do this. 




Farmer Fred

We like to answer your garden questions here on the Garden Basics podcast . There are a lot of ways for you to get in to ask us these questions. You can leave an audio question without making a phone call, via SpeakPipe. Just go to speakpipe.comgardenbasics and yell at your computer. Call us or text us the question at 916-292-8964. You can fill out the contact box and ask the question at our homepage, gardenbasics.net . E-mail? Sure, why not. Fred at farmer fred.com and get your questions in. That's exactly what Ben did. He lives in North Texas, zone 8B. 

Ben says, “I have a variety of grow bags and containers and I sift my soil and compost very finely. I've added cocoa coir, but after the sifting, I am concerned about compaction. It seems to clump together and it breaks apart easily in my hands. Should this be a concern? And if so what can I add to the mix? Thanks for all the knowledge you've shared. Definitely has helped me be more prepared for my second year growing food.”

 Well good for you, Ben. Very important to get into the food growing habit because the healthiest food you can eat is the food you grow yourself. Debbie Flower happens to be here, America's favorite retired college horticultural professor. You've worked with coir.  You've worked with peat moss. And they both seem rather difficult to work with, unless they're well hydrated.


Debbie Flower  1:53  

Yes, that's important. When I was teaching at the community colleges, we would make our own media rather than buying already mixed bag ingredients. And the base was an organic component. It was peat moss for a long time, that was our base. And then coir came along as a product. It is the hairy stuff that is around a coconut shell. And so it's a byproduct of the coconut industry, great idea to repurpose something like that. When it first started on the market, it was very salty. If you think about it, coconut palms grow around oceans. And they have this big seed and its biggest seed in the world. And it moves from place to place by floating on the ocean, and then it gets up on a beach somewhere, and it germinates and grows. That's just a little bit of trivia there.


Farmer Fred  2:45  

The biggest seed in the world.


Debbie Flower  2:47  

Yeah, it's a coconut. It was coming from salty environments because of the salty oceans. And so it had to be washed. It had to be wetted before it was used because salt, sodium, the salt like we use in our food, and like it's in the ocean. It is very bad for most plants, and we'll kill them. But we would buy it in bricks, and the bricks had to be soaked because you couldn't deal with them. They were so tightly compacted. So yes, I've seen compacted coir. But when you soak it, it absorbs the water and expands. And we would soak it overnight and then drain it and then use that as our organic component in the growing media. What I experienced was that when we then grew plants in the media that was made with coir, students over-watered them, because it appeared that the coir on the surface of the container of whatever was growing was dry. Although it wasn't. That's something to watch out for when using coir. Don't rely on the appearance of the media, as to whether it's wet or dry. Pick up the container, see how heavy it is. And you'll see how much water is in there. Once you have wet it initially and used it in your mix, then I don't think it's a problem for compaction. You say you're sifting your soil and compost very finely. I don't know if there is a fine version of coir, do you Fred?


Farmer Fred  4:10  

if you use it dry it's very fine. Right?


Debbie Flower  4:14  

So sift it first and then make the media and then then soak it?


Farmer Fred  4:18  

I think I would soak it first in a big bucket of water overnight and then sift it.


Debbie Flower  4:23  

Then sift and then do it that way. Yeah, I don't know if it'll be as fine as Ben’s. Depends what he's sifting it through it. When we used peat moss at Sierra College we had a piece of - it wasn't chicken wire - but it was wire with holes, maybe inch, half an inch, maybe three quarters of an inch across. Somebody's job during lab was to sit and run peat moss over the top. We had a garbage can and we'd cut a circle out of the lid of the garbage can, attach this grid of metal to it. And they would sift. 


Farmer Fred

like hardware cloth. 


Debbie Flower

Yeah, sift the peat moss. s


Farmer Fred  5:01  

Sift it with their bare hands? This was punishment.


Debbie Flower  5:05  

You would get the person who says, “I can't work today I have a bone in my knee.” OK, you sift the compost. Sit there and sift peat moss.   No, we would wear gloves.


Farmer Fred  5:16  

 You did that before you watered it? 


Debbie Flower  5:20  

Yes. Okay. But when I went to American River, we didn't, we just opened the bale threw it on the ground,  a whole class would do it. So it'd be 15 to 25 people have shovels, and I called it doing the dance, you'd have to chop it with your shovel and then flip it over and chop it with your shovel flip it over. And then everybody would walk two steps ahead. So that because your technique is different than my technique, and so it would result in better separating of the peat moss pieces.


Farmer Fred  5:50  

Now when I was in that particular dancehall, at American, I remember, there was a person with a hose and sprayer, and in that hose and sprayer was some Dawn liquid detergent, to be used as a surfactant. And basically, as the the piles were spread out, they would water that pile right? And do it over and over.


Debbie Flower  6:12  

Yes, yes. And there are official chemicals that you can use as surfactants. So we sometimes had that. And sometimes dish soap did it, you don't want to use too much, just enough to break down the surface tension of the water so that it will coat the peat moss. Because it's such a large volume, we're using multiple bales of peat moss, the big bales, at one time, we probably made a cubic yard of media at any one time. A cubic yard is three foot by three foot by three foot. So that's a big pile of media. You know, when I do it at home, I can use warm water, I can use my hands, but we didn't have that luxury because of the volume we were making. So we had to keep turning and wetting and turning and wetting and turning and wetting and use a surfactant to make sure it gets everything moist.


Farmer Fred  6:57  

You know what I like to do, on a smaller scale, myself too: if it's peat moss or coir is to take that dry bale because it's so dusty, I don't really like to work with it when it's that dusty, and put it in a bucket. So I actually I would only fill up maybe a quarter of the bucket. And then put water until the water topped that existing peat moss or coir that's in the bucket, and then put another quarter’s worth of peat moss or coir in there and add more water and sort of layer it in that way until the bucket was full. And it was topped with a couple of inches of water. And like I said, walk away, come back tomorrow. And it will be so wet, but then you have to wring it out. And the way to do that is to dump it from that solid bucket into a large planting pot, a 15 gallon or 10 gallon pot and let it drain for a couple of hours or so. And then you have some really nice moist, thoroughly moist, media. But like you always talked about to is get in there with your hands and mix it up. All right to move it around because there's always some dry spots. 


Debbie Flower  8:04  

Yes, yes, that's that's the challenge. And using the little bit of Dawn detergent helps get the water everywhere, but you do need to agitate it. We did it with shovels at school and at home I use my hands to get to those dry spots.


Farmer Fred  8:18  

Now the nifty thing about talking about this is that this is also a way to reuse your old potting soil. Walk us through that.


Debbie Flower  8:26  

Container media or potting soil has a large component of an organic base: compost, peat moss, coir are commonly used organic bases for potting media. They break down over time, just like a compost pile does. And so they get smaller and smaller and the spaces between the particles in your mix, your media gets smaller and smaller. And eventually water won't penetrate it anymore. There just aren't enough spaces. And so that's one reason that we need to transplant plants and knock off as much of the old media as possible. And I collect that. The other reason is you grew 20 plants and you let some of them die and you just have leftover media or they died of their own volition much to your sadness, those I'd be careful of. You want to make sure that they the death was due to maybe neglect, they just dried out or something not due to  fungal or bacterial disease that would be transmitted with the media. Those I throw out. So I collect old media and I put it in a container and then I revitalize it. And to revitalize it, you typically need to add some more of the organic component. So that would be the peat moss, compost, the coir, and maybe some of the rock component. If I've used vermiculite as one of the rock components that can compress over time, If I've used perlite, it can break up over time, and I'll need to replace some of the rock component, and then you'd go through the same process of wetting and turning, and then you reuse it. Pumice is my favorite rock component. Pumice is produced by volcanoes. Actually, it comes in different sizes and you can buy it in a horticultural version at your local nursery, and it's heavy. So if you have it shipped you're gonna have to pay a lot of shipping. But it holds up better over time in container media as the rock component of that container media. So it creates good open pore spaces for water and air to travel through, you have healthy roots, it is physically heavy. As I said, when we did this at school, the students complained that their pots weighed too much.


Farmer Fred  10:42  

And your defense was, this won't blow over in the wind.


Debbie Flower  10:44  

Right? But it worked very well for its job of  opening up the media. So that is something I like. I always keep a little perlite and vermiculite around, particularly for seed mixes and seed starting mixes. Pumice is too heavy. If you start  seed in a pumice mix, this little plant probably can't push its way out. I don't like perlite much for anything other than seed starting, mostly because it is very, very dusty. And the dust perlite produces is very irritating to the respiratory system and not just your nasal passages or your mouth. It goes down your throat and into your lungs and you feel it for days. At least if you work around it as much as I did. So wet it before you use it. I break it up in the bag and put the water nozzle right in the bag. Try to wet that puppy. I don't want anybody to breathe it. Wear a mask. When working with perlite, perlite is white. Sort of looks like mini popcorn. Vermiculite, it's not so bad, in terms of the dust. I haven't had any problems with it at all in terms of the dust, but it is expanded mica and it is very flat and it easily crushes  over time. So it's still a rock, it's still in your media. It's just not creating the spaces to both hold water and give water up.


Farmer Fred  12:04  

What ratio, when you're rehabbing the soil mix, you're using, obviously, parts of the old existing potting soil and you're mixing in new combos, maybe new peat moss, maybe new coir, but pumice. How much pumice would you put into the new mix?


Debbie Flower  12:22  

Well, the basic classic media container media recipe is one to one to one. Perlite, vermiculite and at the point if it's been heavily use, you know you've had a plant in there for six months or something, then I would consider the used potting mix to be the organic component, the peat component, then the other two thirds or maybe half. It depends what I'm growing as well. How much water does that plant need? Am I going to put succulents in here? Then I'll go heavy on the pumice. Am I going to grow zinnias in a pot in this? Then I would probably go lighter on the pumice, I might just do 1/3 pumice  or maybe I'll do a third pumice a third vermiculite and a third of the used potting mix. The reason the vermiculite is good with plants that need a steady supply of moisture is the water gets trapped inside the ins and outs  of the structure of the vermiculite.


Farmer Fred  13:21  

So you wouldn't use vermiculite on  that? Or maybe you would use vermiculite if you're doing succulents.


Debbie Flower  13:27  

If you buy a succulent mix, it wouldn't have vermiculite in it. You could, though. it's going to hold some moisture, that's all. So you just want to be heavy on the pumice.


Farmer Fred  13:38  

And so you would use more pumice for succulents. 


Debbie Flower  13:42  

Yes, because they need excellent drainage and the Pumice is bigger. And it creates more open airspace and that's what they need. 


Farmer Fred  13:50  

All right. So basically, that's the way to go. And water is your best friend, Ben, as far as stopping the clumping and the difficulty working with it. It's a lot easier to work with both peat moss and coir when they have water thoroughly mixed into it. And as you say, Debbie, you got to get in there with your hands to mix it up to make sure that it is all wet.


Debbie Flower  14:11  

and then  we introduce a rock component to create openings in your media. You shouldn't have compaction after those techniques.


Farmer Fred  14:19  

And finally, here's Debbie's tip for removing all that junk that's in your fingernails now. 


Debbie Flower  14:32

After doing that, wash your hair. Oh. And that will remove the dirt under your fingernails.


Farmer Fred  14:32  

Good. All right, there you go.


Debbie Flower  14:34  

I mean, I use a nail brush and everything, but  washing your hair does it the best.


Farmer Fred  14:40  

We have tips for everything in life here at the Garden Basics podcast. Debbie Flower, once again, thanks for showering.


Debbie Flower  14:45  

Yeah, you and everybody else.




Farmer Fred  14:55  

In Friday’s Beyond the Garden Basics newsletter, we do a deep dive into a subject we touched on in today’s podcast: making your own potting or planting mix. If you start a lot of plants from seeds, or like to transplant into containers, you save a lot of money over commercial mixes by blending your own healthy ingredients. Thinking of using your own garden soil for seed starting or container gardening? Think again! Your backyard dirt carries the risk of short circuiting your garden efforts with soil pathogens such as disease spores, weed seeds, microscopic-sized pests and insect eggs. And blending potting mixes yourself, especially for starting seeds in spring, is good for your emerging plants and your disappearing wallet.

Make your own planting mixes. It’s this week’s topic in the Beyond the Garden Basics Newsletter, on Substack.There’s a link in today’s show notes. You can also find it at the newsletter tab at the top of our home page, gardenbasics.net . Or go to substack.com slash garden basics (one word).  Think of it as your garden resource that goes beyond the basics. The Beyond the Garden Basics newsletter. 




Farmer Fred

 We get an email from Darren who writes in and says, “Hi Farmer Fred. I have a dwarf plum and dwarf apple tree, spaced about 10 feet apart. They're both about four years old. But that Plum is not exactly a dwarf at the rate it's growing. It needs constant pruning. Anyway, despite drip irrigation, the plum has sent a one inch root all the way to the apple tree on the ground surface. My guess is that it won't be the first. Is this going to create problems for the apple tree? And if so, can I cut this and future roots? Thank you.” 

Thanks for writing in, Darren. If you stay on top of keeping that plum tree at a manageable height ,then with that should help limit the root spread. Plums are by nature, very aggressive growers. And don't worry about any sort of grafting going on in the roots between the apple and the plum. Those two trees are of different genuses. Aplum is a Prunus, and Apple is a Malus. They will be  okay. Now I would wonder why that root has taken off towards the apple tree. I have a funny feeling, it might be there's more water around the apple tree. Maybe the area around your plum tree is drier than the area around the apple tree and that plum is looking for more water. For fruit trees, I prefer using micro sprayers instead of drip emitters. Three or four 90-degree spray micro sprayers that are placed towards the outside of the tree and facing inward can do a great job of watering that entire soil mass that's below the tree. Maybe then your plum would be happy. I wouldn't cut any roots unless you absolutely have to. So the first thing I would do is check the soil moisture between the plum tree and the apple tree. I have a funny suspicion that where that root from the plum tree is headed, it's going to where water is more plentiful. So check that out first, and then maybe rework your drip irrigation system with micro sprayers. And of course if you don't want to trip over that root that's running along the surface, add three or four inches of mulch beneath the trees, that'll do it. 


Farmer Fred

Garden Basics with Farmer Fred comes out every Tuesday and Friday. It's brought to you by Smartpots. It's Garden Basics, available wherever podcasts are handed out. For more information about the podcast, and transcripts of the podcast, visit our website, gardenbasics.net . And that's where you'll also find out about the free Garden Basics newsletter, “Beyond the Garden Basics.” And thank you so much for listening.


Comments & Upvotes

Contact Us


Got a question, press inquiry or idea you'd like to share? Contact us through the form below and let us know how we can help.

Subscribe, don't miss the next episode!