Container soil getting compacted

Coolbreeze89

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I have containers that I filled with 50/50 compost and potting soil in March. I went to transplant a couple plants that seemed a bit stunted, figuring they needed a bigger space (currently in 5-gal buckets). I found that the bottom half of the containers were completely compacted in both. I’ve researched how to improve soil density, but the consensus seems to be “Add compost”. I’m suspicious, however, as the compacted material smelled and looked like what the bottom of my compost barrels look like: wet and a bit...rotten? Not the good humus smell. My compost has a high sand content, as my ground is fine white sand that gets picked up when I collect the goat/sheep/chicken poo. The manure gets mixed with either old pine shavings from animal bedding or fallen leaves (in the fall). It “cooks” for 6+ months and I only use it when it smells like good soil.

Any suggestions of what I can add to my soil mix, or other ideas of what I at best doing to exacerbate this issue? I’m in 8b Central Texas and we’ve been HOT (110+ heat index) so I’ve been watering daily trying to keep everything alive. All containers have many drain holes (though I think the solid mass may be obstructing outflow - I’m going to try adding a few more holes and perhaps lifting the buckets to give more space to drain).
 

Ridgerunner

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Since March has been a long time. It sounds like your compost was finished so that's not the culprit. I often find more shredded bark or wood in potting soil or garden soil that I'd want. Those can take a while to break down.

To me it sounds like you still have organic material in there that is breaking down and it is too wet. Since it is wet the microbes that break it down have gone anaerobic (no oxygen). That can have an ammonia smell to it, not a good loamy smell. They tend to be sticky and slimy too.

I'm not much of a container gardener, I have too much problems getting the water right. That's as much over-watering as under. To me it sounds like you are probably over-watering but I'm far from an expert.
 

Coolbreeze89

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Since March has been a long time. It sounds like your compost was finished so that's not the culprit. I often find more shredded bark or wood in potting soil or garden soil that I'd want. Those can take a while to break down.

To me it sounds like you still have organic material in there that is breaking down and it is too wet. Since it is wet the microbes that break it down have gone anaerobic (no oxygen). That can have an ammonia smell to it, not a good loamy smell. They tend to be sticky and slimy too.

I'm not much of a container gardener, I have too much problems getting the water right. That's as much over-watering as under. To me it sounds like you are probably over-watering but I'm far from an expert.
Thanks. I’m going to try reducing the watering and see how everything does.
 

Dirtmechanic

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I potted 20 tomato plants with a topsoil mix of clay and bark for 2 parts added vermiculite 2 parts, perlite 1 part and black kow compost 1 part and fertilizer. This compost thing is a problem. While plants naturally do well with more compost, the beginnings of that are in the 5-10% range. It has been studied an proven that after 30% you not only begin to waste resources, but like you are experiencing, one can cause a decline in plant vigor. Oxygen and drainage are the major components of this of course, especially in solid wall pots that cannot breathe. I used grow bags which breathe well, just because I had them due to a button pressing condition I experience when on the Amazon app.
 

Milosevich Garden

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@Coolbreeze89
It sounds to me that you "soil mix" has lost its aeration and that left your soil to compact.
You said that you used a 50/50 mix of potting soil and compost, compost adds very little aeration even with sand in it and the aeration that is in most potting soil is perlite it most likely washed to top or collapsed in to a dust.

I been growing in container for 4 years now and the containers that I use range from 5 to 30 gallons. The soil that I started with day one is the same soil I'm using now, never changed.

One of the best "DIY" container base mixes I found is a mix from Clackamas Coots which is a very simple mix and consists of
1/3 - Compost and or Worm Castings
1/3 - Peat Moss
1/3 - Aeration (small pumice, small lava rock, Groestone (GS-2), Hydroton (4mm – 16mm size) and or rice hulls (small being pea size +/-)
Then add a nutrient mix as directed by the company. (I use GreenGro Veg and it recommends 1 cup per cubic foot of soil and side dress 1Tbsp per gallon of media once a week.)

Another good mix would be.
5 parts Peat Moss
2 parts Aeration
1 part Compost
Then add a nutrient mix as directed by company.
This mix is good if you have a less than ideal or imbalanced compost.

With both of these mixes I recommend doing a soil test or at very least a pH test to balance the pH as needed.
If you need to "sweeten" the soil (you most likely will) you can add Gypsum, Lime and or Oyster Shells.

These mixes are a good start and with some time and research you can fine tune it to your needs.
Amendments like Biochair, Green Sand, Azomite, Humic Acid, Langbeinite, Gro-Kashi and also mycorrhizae and beneficial bacteria can help "polish" you soil.

I would also recommend if your growing Determinate or Indeterminate tomatoes to go to a minimum container size of 15 gallons, I grow mine in 30 gallon containers and the roots reach out to all edges of the containers.
 

Coolbreeze89

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Thank you all for your input! I’ll be re-doing my soil mix to reduce the compost component and improve the aeration - time to research what’s available to me of all the suggested options.
 

Coolbreeze89

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I potted 20 tomato plants with a topsoil mix of clay and bark for 2 parts added vermiculite 2 parts, perlite 1 part and black kow compost 1 part and fertilizer. This compost thing is a problem. While plants naturally do well with more compost, the beginnings of that are in the 5-10% range. It has been studied an proven that after 30% you not only begin to waste resources, but like you are experiencing, one can cause a decline in plant vigor. Oxygen and drainage are the major components of this of course, especially in solid wall pots that cannot breathe. I used grow bags which breathe well, just because I had them due to a button pressing condition I experience when on the Amazon app.
Which grow pots did you buy/would you recommend? As I am trying to amend the soil, my “food grade” 5-gal pots are cracking on me. So, I’m getting my Amazon order going!
 

Dirtmechanic

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Which grow pots did you buy/would you recommend? As I am trying to amend the soil, my “food grade” 5-gal pots are cracking on me. So, I’m getting my Amazon order going!
I used 7 gallon bags and picked up these round green trays for them to sit it. The bags air prune the roots which is pretty cool.

The bags of which I bought 4 sets of 5:

The actual bags I bought. Get a lighter color though.:

2 sets of 10 Saucers for setting the bags and reservoir:
 
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