I have a lot of container plants. I have been trying to reuse soil but I run into problems.
The reused soil, even with additional fertilizer does not have vigorous plants. I use peatlite 50/50 peat moss and perlite by volume. Added 2 cups of 6-4-6 + osmocote (approx 1/4 cup) per 18 gallon container.
Initial crop does fine and gets good yields, but problems when soil is reused
1. Poorer growth despite using the same amount of fertilizer as the orginal mix
2. Pots are holding too much water and it gets worse when it rains.
3. I used to just use potting soil once and put the remains in they garden or yard. It does not cause issues there except for weeds. I do scrub and bleach the pots before reusing.
4. I tried taking out half the soil and replacing with fresh new soil. It works unless the roots have to go to the bottom of the pot.
5. The soil on the bottom is muddy and somethings smells bad.
6. I started now removing all of the soil to refluff it and mix 50% new soil with 50% reused soil and added the same amount of fertilizer. This helped with the soil being more uniform, but more weeds appear.
7. I've noticed after 3rd attempt at reuse, plants grow but are smaller. Organic fertilizer caused issues, so I have gone back to synthetic so I am no longer seeing nutrient deficiencies.
8. The older soil looks like the peat moss has become more muddy. Even with large amounts of perlite, the soil is not really compacted and drains well, but just does not dry out and I have more fungal issues.
9. The information I read says to add more compost, but I have always had issues adding compost to the pots, namely the pots stay very wet and nothing grows.
10. I found an article that said that adding organic bark mulch improves drainage. It is not that easy to find. I am now adding shredded bark nuggets, which are more like shaved wood chips they are quite big pieces. They are not composted, so I have to compensate with more fertilizer. I just started this, so I don't know yet if it will help or not.
What kind of compost of organic matter can I add to the pots to relieve the compaction problem from the break down of the peat moss, but won't hold on to more water?
How much to add and what percentage of the final mix. old soil, new soil, organic components.?
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applestar
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I need to pay more attention like you do because I don’t want to keep buying potting mixes or at least less, but I haven’t figure it out.
If I can, I’ll try to grow more vegs in containers this year so I can actually see what happens in successive use.
So for now, my ideas will be vague and uninformed — see what you think and try what you haven’t before I guess?
— I always add compost worms and deeper delving earthworms to my containers. Compost worms stay near the surface and process the plant debris, and the deepe delvers (night crawlers?) like to curl up in the clay chunks and bottom corners of the containers in search of minerals. They both help aerate and exude biologically active mucus which invigorates the microbial activity.
— I always use crushed dolomitic lime — for the extra minerals including magnesium — rather than straight lime (I’ve learned straight/quick lime can be processed by adding to a bucket or large jug of water and then decanting the liquid after 24+ hours to use very weakly diluted)
— I have been using bokashi as potting mix supplement for a while now. The beneficial microbes are anaerobic and help to outcompete with the inimical microbes in the waterlogged and oxygen-poor conditions especially in deeper containers and SIP.
— I drill holes and cut slits in sides of deeper containers so the roots have access to air
— I have been making HOME brewed beneficial microbe cultures — these are mostly random combinations of baking yeast, lactobacilli cultures like yogurt and miso, natto powder (because I can’t get fresh/frozen natto easily), soy and other plant-based milk (eg Rice Dream), leftover cows milk and various juices, brown sugar and/or molasses… etc. This also gets added to potting mix as well as used for supplemental “watering/feeding”
— I also make the “green juice” — growing tips of mugwort and related “weeds” mixed with brown sugar and cultured — resulting exudate is decanted and cultured some more and used very diluted
— For non-SIP containers, I have been looking at fig growing mixes and bonsai mixes as reference recipes for my large container mix blends. This includes bark mulch left to “age” for a season (usually little black ants move in, which I eradicate by spreading out on tarp for birds, etc. to dry out and pick over and then treating with borax and soapy water), extra large perlite for hydroponics, and — less easy to obtain so as available — diatomaceous earth sand/gravel and pumice gravel, paver underlayment sand/gravel
— ETA — the bark mulch —using them unconditioned I think leads to nitrogen lockup, so aging or composting is a way to avoid that.
* I think process can be accelerated by mixing with biologically active agent (maybe compost activator would be an easily available alternative) — monitor for pests and moisture content.
* Mycorrhiza is another good way to make the bark nuggets more bio-available. Mixing with premium potting mixes infused with good mixture is one way.
* Bagging/keeping in sealed bag using beneficial anaerobic microbes might keep out unwanted pests.
* Always double screen for optimum size and screen out “fines” from container mix (use the fines for seed starting)
If I can, I’ll try to grow more vegs in containers this year so I can actually see what happens in successive use.
So for now, my ideas will be vague and uninformed — see what you think and try what you haven’t before I guess?
— I always add compost worms and deeper delving earthworms to my containers. Compost worms stay near the surface and process the plant debris, and the deepe delvers (night crawlers?) like to curl up in the clay chunks and bottom corners of the containers in search of minerals. They both help aerate and exude biologically active mucus which invigorates the microbial activity.
— I always use crushed dolomitic lime — for the extra minerals including magnesium — rather than straight lime (I’ve learned straight/quick lime can be processed by adding to a bucket or large jug of water and then decanting the liquid after 24+ hours to use very weakly diluted)
— I have been using bokashi as potting mix supplement for a while now. The beneficial microbes are anaerobic and help to outcompete with the inimical microbes in the waterlogged and oxygen-poor conditions especially in deeper containers and SIP.
— I drill holes and cut slits in sides of deeper containers so the roots have access to air
— I have been making HOME brewed beneficial microbe cultures — these are mostly random combinations of baking yeast, lactobacilli cultures like yogurt and miso, natto powder (because I can’t get fresh/frozen natto easily), soy and other plant-based milk (eg Rice Dream), leftover cows milk and various juices, brown sugar and/or molasses… etc. This also gets added to potting mix as well as used for supplemental “watering/feeding”
— I also make the “green juice” — growing tips of mugwort and related “weeds” mixed with brown sugar and cultured — resulting exudate is decanted and cultured some more and used very diluted
— For non-SIP containers, I have been looking at fig growing mixes and bonsai mixes as reference recipes for my large container mix blends. This includes bark mulch left to “age” for a season (usually little black ants move in, which I eradicate by spreading out on tarp for birds, etc. to dry out and pick over and then treating with borax and soapy water), extra large perlite for hydroponics, and — less easy to obtain so as available — diatomaceous earth sand/gravel and pumice gravel, paver underlayment sand/gravel
— ETA — the bark mulch —using them unconditioned I think leads to nitrogen lockup, so aging or composting is a way to avoid that.
* I think process can be accelerated by mixing with biologically active agent (maybe compost activator would be an easily available alternative) — monitor for pests and moisture content.
* Mycorrhiza is another good way to make the bark nuggets more bio-available. Mixing with premium potting mixes infused with good mixture is one way.
* Bagging/keeping in sealed bag using beneficial anaerobic microbes might keep out unwanted pests.
* Always double screen for optimum size and screen out “fines” from container mix (use the fines for seed starting)
I haven't used my own mixes for seed starting and not for transplants destined for the garden. What I'm able to accomplish in a mix, I wouldn't trust for plants only a few days or weeks old.
However, it goes in pots for perennials. An organic potting recipe that I came across years ago using compost, peat moss and perlite equally has worked well.
After a season, potting soil of homemade or commercial origins ends up back in my compost. Screening that compost is what I'm doing today. Usually, the compost is capped at the end of the season with garden soil. So, there are a fair amount of rocks from our soil to screen out.
The compost is used not as a mix but 100% and not screened for the potted tomatoes. I don't think that I could ask for much better performance from them. Either mixed and screened or straight -- a simple process.
Steve
However, it goes in pots for perennials. An organic potting recipe that I came across years ago using compost, peat moss and perlite equally has worked well.
After a season, potting soil of homemade or commercial origins ends up back in my compost. Screening that compost is what I'm doing today. Usually, the compost is capped at the end of the season with garden soil. So, there are a fair amount of rocks from our soil to screen out.
The compost is used not as a mix but 100% and not screened for the potted tomatoes. I don't think that I could ask for much better performance from them. Either mixed and screened or straight -- a simple process.
Steve
I have been taking all of the soil out of the pots. I am finding a layering effect if I just take out half and put new potting soil on top. Mixing new soil works. I can only do this with potting soil that still looks good, that is it doesn't look like the peat moss has turned to fine dust or mud. When the potting soil does not look good, I do actually still use it around the yard. I used to add it to my garden, but I haven't been doing that lately.
I did try hot water sanitation of the media. Unfortunately, it was expensive since neither the microwave or the stove can tolerate the heat from boiling water for hours at a time. I would have to borrow a propane stove and a large pot to boil the water.
I don't have nutrient issues as long as I use the complete fertilizers. I am doing more water soluble fertilizers than before in the containers. I do add vermicast to the potting mix when I have it and some pots do have earthworms. If I find them in old pots, I put them in the other pots.
I saw a youtube video and they said to use shredded hardwood mulch or composted soil conditioner. I have Kellogg's garden soil, which is primarily wood fines. I am looking around for hardwood mulch. I really want leaf mold. I used that at the garden, but it takes a year to make it and I have to have clean leaves. Two things that are hard to come by.
I cannot use my garden soil, because I do have nematodes. It is one of the reason why some plants like tomatoes and okra are in the pots in the first place. They are not necessarily nematode resistant. It is also why I only put Contender beans in the garden. It is nematode resistant. But, I could put Poamoho beans there as well, they are nematode resistant too. I just have to stake them. The stakes could not be used in the pots.
I usually over fertilize my containers, so I will need to see if the bark chips cause issues. Only time will tell how much of a problem that would be.
I have black cinders. I can put that in the pots, but it may cause problems for root crops like carrots, and daikon. It should not bother the beets because more of the beets are above ground and the farm grew beets in cinder bio filters so it does fine. Crushed cinders would add mineral micro nutrients like boron. I do get boron deficiencies showing up in the beets using soil less mixes. I have to check to see if there is a benefits to adding cinders or gravel to a potting mix for drainage. It would make the pots very heavy.
I did try hot water sanitation of the media. Unfortunately, it was expensive since neither the microwave or the stove can tolerate the heat from boiling water for hours at a time. I would have to borrow a propane stove and a large pot to boil the water.
I don't have nutrient issues as long as I use the complete fertilizers. I am doing more water soluble fertilizers than before in the containers. I do add vermicast to the potting mix when I have it and some pots do have earthworms. If I find them in old pots, I put them in the other pots.
I saw a youtube video and they said to use shredded hardwood mulch or composted soil conditioner. I have Kellogg's garden soil, which is primarily wood fines. I am looking around for hardwood mulch. I really want leaf mold. I used that at the garden, but it takes a year to make it and I have to have clean leaves. Two things that are hard to come by.
I cannot use my garden soil, because I do have nematodes. It is one of the reason why some plants like tomatoes and okra are in the pots in the first place. They are not necessarily nematode resistant. It is also why I only put Contender beans in the garden. It is nematode resistant. But, I could put Poamoho beans there as well, they are nematode resistant too. I just have to stake them. The stakes could not be used in the pots.
I usually over fertilize my containers, so I will need to see if the bark chips cause issues. Only time will tell how much of a problem that would be.
I have black cinders. I can put that in the pots, but it may cause problems for root crops like carrots, and daikon. It should not bother the beets because more of the beets are above ground and the farm grew beets in cinder bio filters so it does fine. Crushed cinders would add mineral micro nutrients like boron. I do get boron deficiencies showing up in the beets using soil less mixes. I have to check to see if there is a benefits to adding cinders or gravel to a potting mix for drainage. It would make the pots very heavy.