new sustainable potting mix

[rainbowgardener]

So my stuff for making potting soil arrived, just in time because I was just about out of last year's.

I have 40 pounds of mushroom compost, 5 kg of compressed brick coconut coir (expands to 3 cu ft or 16 gallons), and 1 pound of rice hulls. The rice hulls are very light and dry and a little goes a long way. They are tan colored and the size of a rice grain, which gives a kind of coarse texture to the mix, less than ideal for tiny seedlings.

They are plant derived, not mineral like perlite, so I'm wondering if they are going to break down a lot faster than perlite. Remains to be seen.

The 40 lbs of mushroom compost costs $4 at local big box. The coco coir costs about $10 plus some shipping (I haven't looked around yet to see if I can find a local source). But it is small and light and the shipping isn't outrageous. However, I have NOT been able to find any local source of the rice hulls. For some reason, my little 1 lb bag of rice hulls cost $3 and change PLUS $15 shipping. I really wanted to try it so I bit the bullet, but if I can't find a local distributor, I will not do that again and I will be back to the drawing board for a perlite replacement.

I really like this mix because all of it is just waste products from growing other things, stuff that might be trashed otherwise. Easily renewable and keeping stuff out of the waste stream.

I made up about 3 gallons of potting mix, using about 1/4 of the bag of mushroom compost, 1/8 of the coco coir bricks, and maybe 1/3 of the rice hulls. That is about equal parts of compost plus coir, plus a little bit of rice hulls, less than 1/2 a part. I figure if you ignore shipping costs, because I won't do that again, that 3 gallons cost me about $4. Plus I added 1 cup of soaked alfalfa pellets, about 1/4 cup dry.

Miracle Gro costs $5 for 8 quarts, so as long as I don't pay shipping, my mix is not only more sustainable and eco-friendly, it is cheaper. So I'll keep looking for a local rice hulls distributor.

PS I did a little more looking now and found Midwest supplies offering the same pound of rice hulls for $1.50 plus $6 shipping. Don't know why I couldn't find them before. That would have been a lot better, but I would still like to find someone in town that sells them. https://www.midwestsupplies.com/checkout/cart/

[Bobberman]

Good link Midwest supply Thanks!! They have some nice thermometers on their web also.!

[rainbowgardener]

the link was supposed to show the rice hulls. Here's the home page: https://www.midwestsupplies.com/

you can see it is a homebrewing beer and wine site. Apparently the rice hulls can be used for that also. Something about the way I was searching the first time, probably didn't pull up beer and wine sites.

[rainbowgardener]

In the meantime, I had more broccoli seedlings that hadn't been potted up and more little celery seedlings to transplant to individual cells. That means I can do a side by side comparison of how they do in regular potting soil vs my compost/ coir/ rice hulls / alfalfa pellets mix. I did have a little bit of old Miracle Gro potting soil around from previous years that I was using up in some of my pots, so this will be a direct comparison of MG vs homemade.

[applestar]

Sounds good! I'll be following thus thread.

[skiingjeff]

I need to find a local place for some mushroom compost to add to the potting mixture. Did someone say Agway's may carry it?? I'm also searching the web to see if we have any mushroom farms in the Northwest CT to Southwest Massachusetts area.

Anyone know of a good source? Thanks!

[Bobberman]

Agway had cow manure compost and mushroom compost and they are both in 40 pound bags for around $4. I bought 4 bags of each last year. Its very fluffy and very nice! I mixed it with my strained garden soil along with sand and started my seeds in it and it worked great!

[skiingjeff]

Thanks for the confirmation on the Agway stuff! I'll have to wander over to our local Agway dealer and see what they've got!

[baileysup]

That sounds like a great mix rainbow. Let us know how you like it. As, far as Agway goes, I get just about all of my materials there. Pumice (Dry Stall), Turface (Pro Field Field Conditioner), and they also have good mushroom compost. The only thing I can't find locally, is the coconut coir. I must order that online, but it's not that expensive. Still can't find pine bark fines either, so I just get a big bag of pine bark nuggets from Lowes, and blend them in the blender. So far so good with this mix, though I haven't needed the mushroom compost yet, I can use it in the future. Especially at $4.25 per 40lb bag.

[rainbowgardener]

I am well in to seed starting season and I am liking my mix real well. The mushroom compost is cheap and easy to find. The coconut coir I ordered on line too. It comes in very compressed bricks which expand to something like 8 times their size, so it lasts a long time. So I am half way through my second 40 # bag of mushroom compost, but only half way through my first 10 # of coconut coir bricks. The rice hulls are the hardest. I found one on-line supplier ( https://www.midwestsupplies.com/ )where I can get 2 # of rice hulls for about $10, half of which is shipping. I started with one pound the first time, but the shipping & handling is about the same for 2# as 1 # so it makes it a lot cheaper over all to buy two. Since I am well on the way to using that up, I may order 3 # the next time. That should get me through the season. It would be about $12 for 3 #, so ordering in bigger quantity really brings the price down.

It is kind of fun - apparently some actual rice grains get left in with the hulls, so my potting soil sprouts rice plants. Not enough to be really obnoxious. It took me awhile to figure out what they were. Since I did, I've been potting them up. I now have about 20 little rice plants in individual cells. I've never grown rice before, so since they are a free bonus of my soil, I thought I would try.

My mix has a nice texture and is good to work with and seems to be growing well. Compared to growing in potting soil with Miracle Gro, it is not as nutrient rich, so I have to work a little harder to amp it up. I use soaked alfalfa pellets, used coffee grounds, aerated compost tea, worm castings when I have them or whatever else is on hand to make it a little richer. Some of my green pepper plants are still a little bit yellow, but everything else seems to be doing fine.

[drh146]

How or where do you store it? In a pile outside? Pissed buckets? Or are you using it all at once?

[rainbowgardener]

None of it takes up as much room as it might sound like. The coco coir bricks are very compact until soaked. I have a bunch of boxes and plastic buckets next to my seed starting area (indoors). It makes the place look pretty cluttery, but it isn't for much longer and then everything will get cleaned up and moved to the shed. Indoor seed starting is declared done May 1!

[skiingjeff]

Indoor seed starting is declared done May 1!

RBG, I know you mentioned you aren't doing cauliflower but I heard that it is better to always seed them in pots and then transplant the starts into the garden. Have you or anyone else had any experience with this or heard of this being better? If so, would it be better for broccoli and other related plants?

If so, my seedling process will continue in the summer to get Fall starts for cauliflower, at least.

Thanks!

[rainbowgardener]

I do start broccoli (and cauliflower if I do it, which is not usually) indoors in the spring, because otherwise it is hard for it to have enough time to make heads before it gets too hot for it. I have planted broccoli seed in the ground in late Sept or Oct. It doesn't make a fall crop that way but it gets started and then over winters (assuming we don't have a winter like the one just ending) and gives a really nice early spring crop. I think that is the best way to grow spinach and broccoli. They get going early while it is still cool, they have more time to keep producing, and there's few bugs around to bother them.

I have never really managed a fall crop. I'm thinking about trying it this year, but I think that will mean turning the indoor lights on again. Not so much because they couldn't be planted in the ground, but because at the time they would need to be planted (Aug) all the summer crops are still going strong and the beds are full. In my very limited garden space, it is hard to have room to plant them at that point.

[skiingjeff]

@RBG - interesting ....you plant seed in the ground in Sep/Oct and it germinates and grows and then goes dormant over the winter. Do you provide it any protection during the winter??

I understood broccoli can take some frost but wasn't aware it would take a hard freeze with snow packed on it. Or are your winters milder than ours along the CT/MA western border??? I'm thinking even though I'm classified as Zone 6a because I'm on the border of 6 and 5 I might have a colder winter than you?

At what temperature will the broccoli plants die rather than go into dormancy? If it works, how early is early for the Spring harvest?

Sorry about all the questions but broccoli is one of our favorite veggies and if we could get it from the garden in early Spring that would be great!

Is there anyone along the CT/MA western border that has had any experience doing this??

Thanks in advance for the info.

[rainbowgardener]

I haven't given it protection. If I would get it together to do that, it would probably over winter every winter. As it is, it's a little borderline. Some winters it makes it and some it doesn't. Spinach is even tougher and usually makes it.

We do always have hard freezes and snow pack in the winter. They withstand it a lot better starting from seed in the ground in early fall. They are automatically adapted/ hardened and have plenty of time to gradually get themselves ready. Trying to bring plants that have been started and growing indoors out in the spring is a lot more difficult. It takes a lot of hardening before they get frost tolerant.

I didn't plant anything but garlic last fall, which is probably just as well. This didn't turn out to be a winter that much would have survived. The garlic did great and is growing again. If I had planted them and they had survived, I would be eating broccoli and spinach from the garden now, which is wonderful!

I looked back at my 2012 seed starting thread and found this:


"Fall planted broccoli and spinach continue to thrive and be amazingly productive in the new front lawn bed and the garlic there is looking very large and healthy. "

dated 3/29/12 https://www.helpfulgardener.com/forum/vi ... 9&start=30

At that point, I had been eating broccoli and spinach from the garden at least a couple weeks already. I didn't make a note (or if I did, it is in some other thread and I'm not going to keep looking) about when I started harvesting it.

[rainbowgardener]

Incidentally, I am really liking my sustainable potting mix. I planted the first things grown in it in the garden today (broccoli & spinach). It is really nice textured - very loose and just falls apart. The stuff in Miracle Gro seems to get root bound easier, while the stuff in my soil keeps its roots inside the rootball and not circling. And it is better drained. I had some comparison ones that MG and my mix pots were in the same tray. The MG ones came out kind of soggy and my mix was perfect, damp but not wet.

I got my next batch of rice hulls from Midwest supplies. I ordered three pounds, which cost $12 including shipping. That brings my cost down to $4 a pound. Considering how far a pound goes, I don't feel bad about that.

So ... I was prepared to keep using my mix even if it didn't work as well, just for the eco-friendliness of it. In fact, I turn out to like it better, so a double win. Triple win if you consider that now that I have gotten the price of rice hulls down, it is actually also cheaper than MG.

[skiingjeff]

Thanks for the info on the broccoli RGB

Glad your mix is proving to be not just eco-friendly but better for you! Our soil in the garden is still too cold and extremely wet yet. Can't wait to get my plants in the ground though.

Happy Gardening!

[rainbowgardener]

this is a PS. I looked back at this and realized I probably should have specified a little more. When I said I gave the broccoli no protection, I meant I didn't put any plastic over it, no hot caps, hoop house etc. I did mulch it well with fall leaves. Once it is dormant, it doesn't need sunlight, so I basically buried the little plants in leaves.

[rainbowgardener]

Here's another PS re the fall planted spinach and broccoli. I was looking something else up and bumped in to this:

https://www.helpfulgardener.com/forum/vi ... p?p=251976

dated April 15, 2012

it says:

"I have always spring planted spinach. It does ok, but doesn't last very long. By the time it is a decent size for eating, the weather warms up and it bolts. Last fall I planted some in October, too late to get a fall crop. But it overwintered and just took off in early spring. It has thrived more than I have ever seen. I have been eating spinach from the garden since mid-Feb. We've eaten all we could, I froze about a quart of it, and there is still a ton of it out there. It's now about to bolt, so won't last much longer, but it has been great."

As it turned out the fall planted spinach didn't bolt much earlier than the spring planted spinach, all of it bolts when the weather warms up. That means you get months more production out of the fall planted stuff.

2012 was a year when we had a very early warm up in spring, not like this year. So you wouldn't get exactly the same results every time. But still I think this is the best way to plant spinach and broccoli too, if you can protect the broccoli, which is not quite as tough as the spinach at getting through hard winter.

[skiingjeff]

Thanks for the info on the fall planting and links!

I was offline for a few days with a friend who's Dad passed. Now I need to catch up on my seedlings and stuff.

[rainbowgardener]

I've been using used coffee grounds and soaked alfalfa pellets to jazz up the nitrogen level in my home made potting soil a bit. But I ran out of the alfalfa pellets. Until I get more, I've been using soaked dry cat food instead. It is 32% protein (which is always high N) and has soybean meal and corn gluten meal in it, so I figured it would do. So far, so good.

It's that time of year, peak of indoor seed starting, when I am going through potting soil as fast as I can make it. I have about used up my third 40 pound bag of mushroom compost. I used up 5 # of coconut coir and ordered more, which I have started on. I have used 4 # of rice hulls and started on the next bag. I used all the little pots I had on hand (which was I don't know how many hundreds) and ordered 100 more and have about used them up, as well as all the ones from stuff I planted, that I immediately re-use.

When I start on the seed starting in Jan, it is always really exciting and I'm so glad to be working with plants again when it is all snowy out. This time of year, I want to be out and I get tired of the seed starting operation, which is a lot of work when it is this big. But the church plant sale is early this year (4/27), so a whole ton of stuff will be sold off in a month...

[applestar]

That sounds great! It always amazes me how much you grow in economy of space. And the soil mix sounds like it's really working out.

Cat food "tea" was inspired Are you seeing any difference between alfalfa? I'm thinking cat food must be higher in N but alfalfa has natural growth factor and other nutrients, too.

Which is less expensive when all nutrients are considered -- Cheap cat food or alfalfa pellets? What about smell?

[applestar]

Hey Rainbowgardener. So now that you've had the chance to work with your mixture a bit, can you post the (tentatively) final recipe of ingredient ratios for seed starting, and maybe how you would tweak it for flowering/fruiting plants ...say... container tomatoes and peppers? What about foliage plants like lettuce or spinach?

[rainbowgardener]

Woah, applestar, you are so much more sophisticated than I am. I really don't know about tweaking it for different kinds of plants. I've always done pretty much one size fits all potting soil for everything from seeds to container trees. I'm sure that isn't what's recommended, but I'm the no-fuss gardener.

And my potting soil is kind of like your cooking. Hard to give a real recipe because I'm mixing it by hand, eyeballing quantities, in buckets, from whatever is on hand. I'm sure it's never exactly the same twice. So I can't do much better than I already have.

Basically it comes out something like 2 parts mushroom compost, 2 parts soaked and fluffed coconut coir, 1 part rice hulls, 1 part or less of some kind of nitrogen additive (coffee grounds, alfalfa meal, soaked dry cat food).

I have to say that it works fine for the little seedlings. By the time we are talking about big plants, (the foot high transplants) it still doesn't quite have the grow power of MG. I was a little disappointed that the plants I brought for the plant sale were just a bit punier than what I used to bring. Looked fine, no deficiencies, but not that really big leafy look - I think probably a little bit smaller and fewer leaves. I guess that just means that for the future, I still have to work harder on the N additives, especially for the bigger plants. I think fish emulsion would help, but I can't use it with all the indoor and outdoor critters around. Maybe I should break down and buy a bag of well aged composted manure? Would that be too nasty to have in the house? As it was I had a few complaints from Jamie about the smells of alfalfa, cat food, compost tea. My seed starting operation is in an L in the finished basement. Just around the corner, with no doors, is the lounge/ TV room/ music studio.

And I have to admit that I did break down and buy one more bag of MG grow for the repotting project, repotting all the indoor house plants for when they come outdoors. That was some combination of being a little bit worried about big plants & trees that live in their pots permanently and just the lazy factor of having to keep all the ingredients on hand and soaked and mixed. I did use up three 40 pound bags of mushroom compost in the course of the seed starting operation! It is more work, buying mushroom compost one place, coconut coir somewhere else, ordering rice hulls on line, trying to make sure I have enough of all the ingredients on hand at the same time. That is why I broke down on the house plant project. I needed a whole bunch more potting soil and it had to be NOW and it was just easier to go to the big box and buy it all ready made.

But maybe next year I will do better and be more prepared for the repotting...Anyway, there were a whole bunch of bags of MG I didn't use!

So it is an experiment in progress, and as gardeners always say "next year will be better." But I felt proud of my eco-friendly potting soil and to avoid contributing to all the environmental problems, I'm willing to work at it.

[applestar]

Thanks rainbowgardener.
That kind of rough idea was what I was looking for, I don't know how people come up with 1 Tbs of this and 3 cups of that. I agree this is a great idea and I'm really inspired.

I have to uppot/repot all my overwintered indoor container plants and trees as they go out for the summer.

I was thinking of basing the mix on yours -- I have coir and rice hulls -- I would have to get some mushroom compost.

...so if it's OK, I'll list up what I've been thinking of adding...

One part really good organic potting mix with mycos and feather meal, etc. mixing it up at least a few days ahead and giving them a chance to meld. I was thinking about your cat kibble idea. I feed our cats natural food plus supplements so I would have to make a special trip but they are out of cost litter so I need to go to the pets hop anyway. And when you think about it. The lesser cost foods are already made with poultry by-products which I've heard IS feather meal, among other things. Some contain soybean meal and corn gluten (oh wait would that be a problem for germinating seeds? -- well you wouldn't add extra N in the starter mix anyway) Cat food is protein dense which means nitrogen.

For basic nutrient addition, I'm thinking of using soaked alfalfa and bran. I would like to add greensand which I'm out of at the moment, but will probably get. I want to get poultry grit for calcium and lime as well as drainage. Pt his will add to the weight, but uckily my biggest trees tend to prefer acid soil. I want to mix in unsulfured molasses into the moistening water.

I'm also wanting to add equal part as rice hulls of sand just because I've always added sand to my mixes, but that would add to the weight so it may depend on size of container, type of plant, etc. For trees and large containers, I'm thinking 1/2 of the coir could be either coir chip mulch which also come in bricks, or composted small chip mulch if I can find any. Last time I tried, the woman at the cash register assured me they were small chips and what I found after picking them up behind the building and taking them home to open were 2-3" nuggets. (Next time, I'll verify at the pickup point).

I might also blend in BumperCrop as part of the "compost" ingredient. ...I'm completely out of my own compost since I have so much cucurbits this year that I had to ground prep for in addition to the tomatoes which get two towels of compost in the planting hole.

...but that's not even happening yet. First I have to somehow come up with enough soil mix for 24 three gallon and 10 five gallon containers to plant overflow micro and dwarf tomatoes.... On second thought, I'll probably use up the rice hulls I have on those.