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Container Mix help needed

I have a question for the container garden gurus, For those that grow veggies like Tomatoes, Zucchini, Eggplant in pots every year, when do you replace the potting mix/soil if ever. Do you keep building on it, or is there a point in time when it is removed either completely or partially.

I plan on emptying my pots into the compost heap and make some fresh mixes next year, I already do this with my air pots every year but for the planters I usually go three seasons.

In each pot I plan on using;

1) Rotted logs on the bottom
2) My compost
3) Compost from the recycle center
4) Peat moss or coconut coir
5) Black Kow
6) Perlite
7) Rabbit waste (If I have enough by the spring)
8) handful of 10-10-10 don't know why a 8 ) comes out with an emoticon 8) 8) 8) OK I see its in the code
9) 1 gallon of un-composted (I know thats not a word) kitchen waste
10) 1 gallon of charged Bio-Char

a small handful of Epsom salts and Osmocote after plants are established.
handful of blood meal and 10-10-10 once or twice during the growing season.

For the one permanent planter, I'm actually thinking about cutting out the bottom of the pot, removing the pavers and dig down about 12", place the planter over the hole, add some decaying wood, leaves, yard waste, then make up my potting mix.

I usually have a pot for;
1) Leeks
2) Tomato Plant
3) Something like a sweet 100 or sprite
4) Patio Princess
this year I want to try in one of the pots a Hari Eggplant or Listada De Gandia Eggplant


So tips and advice on this would be greatly appreciated.

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imafan26
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Joined: Tue Jan 01, 2013 1:32 pm
Location: hawaii, zone 12a 587 ft elev.

Re: Container Mix help needed

I have not had luck putting compost or manure in pots, but others may have had better luck.

I either use MG potting soil with 1/2 cup of starter fertilizer ( I use vigoro citrus food 6-4-6 with slow nitrogen) or I make my own mix. one part peat moss, one part perlite, 1/4 cup of osmocote and a couple of handfuls of vermicast in a five gallon bucket.

I have not been too successful in reusing the potting mixes, the plants are always smaller the second go around so I usually dump out the soil in the yard and start over.

I have tried to reuse the soil again this year. The plants are a lot smaller so I am trying a different fertilizer 10-20-20 which is fast release nitrogen and see if it helps.

I really should just test the potting soil and see what it needs instead of guessing.
Happy gardening in Hawaii. Gardens are where people grow.

jeff84
Senior Member
Posts: 151
Joined: Thu Feb 16, 2017 3:38 am
Location: southwest indiana

Re: Container Mix help needed

for annuals and heavy feeders once per year it gets dumped and amended. for perennials it gets amended when ever a root trimming is needed.

imafan26
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Posts: 11269
Joined: Tue Jan 01, 2013 1:32 pm
Location: hawaii, zone 12a 587 ft elev.

Re: Container Mix help needed

I can't use wood in my pots, termites would just love that. I don't have black cow here and I can probably throw some more vermicast in the pots. Usually, I take all the soil out on a tarp and I remove all the roots in the pot. I used half the starter fertilizer, maybe that wasn't enough. I usually use 6-4-6. My plants grow but they are small, I am thinking maybe it needs more nitrogen. I usually have enough soil so I don't add more to it and I have not had any luck adding compost or manures to pots, they get too water logged. I think I really need to figure out the fertilizer. I know I need more nitrogen, but I don't know if I need to add some lime. The decaying roots and the added nitrogen, would make it more acidic and I am using an acidic fertilizer in the pots that contains some sulfur. I usually put osmocote in my first potting mix, maybe I should add more when I repot.

My citrus trees are planted in cinder, they need regular fertilizer but once they get into their biggest pot, I have not repotted them. I have had a few escape though, I am having a hard time finding good thick big pots. Citrus trees here don't usually do well past 25 years. There are some older ones but it is rare because tristeza virus is so widespread.

My other perennials get their roots trimmed once in a while and soil added around the sides and bottom but that is all unless they go into a bigger pot. I have to keep moving them once in a while, but I still have a few that went to ground and I have to remove.

I will be following this post to see if anyone has come up with a successful formula for reusing potting soil.
Happy gardening in Hawaii. Gardens are where people grow.

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applestar
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Location: Zone 6, NJ (3/M)4/E ~ 10/M

Re: Container Mix help needed

I don't have enough successful experience to provide a formula either. But one must-have "ingredient" especially in my outdoor containers is wormyworms -- I put big ones in big pots: at least one night crawler from the garden and one red wiggler from a compost pile or vermicomposter. I try to mix up my container mixes when I have finished or semi-finished compost from outdoor piles and/or vermicomposter that contain smaller worms and "eggs".

If I don't have compost to put in, I still add wormyworms along with organic fertilizer -- usually one of the espoma -tones. No nightcrawlers in soilless mixes -- just red wigglers that will do fine with the coir or peat in potting mixes +organic ferts (usually would put in some UCG [used coffee grounds] and UTL [used tea leaves]) -- but if I can, I add chunks of subsoil clay, sand, chunky DE, and nightcrawlers.

Typically my containers sit directly on the unmortared brick patio or on the grass and worms will move in as well.

Depending on availability, I add shredded fine bark mulch in big containers. With some reluctance, I've started relying on horticultural extra large grade perlite sold for Hydroponics. I still don't like the dust and the way they float up and away.... I prefer crumbly rotting log, especially for big outdoor containers.

I've come to the conclusion that redwigglers can be detrimental if they are too big for the size of the plants and containers. They accidentally or intensionally eat the tender roots, especially seedlings suffer. But if they are tiny thread-thin "bloodworms" they can go in with seedlings and still provide support as they both grow -- but this needs to be fast-growing seedlings like tomatoes and not peppers.
Learning never ends because we can share what we've learned. And in sharing our collective experiences, we gain deeper understanding of what we learned.

imafan26
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Posts: 11269
Joined: Tue Jan 01, 2013 1:32 pm
Location: hawaii, zone 12a 587 ft elev.

Re: Container Mix help needed

Compaction is an issue. At the garden they always mix some new soil with the old and it does help with the fluffing. I do have earthworms in my pots. I usually throw them back in. I don't usually add much soil to my reused media, but maybe it wil help to add some new to the old.
Happy gardening in Hawaii. Gardens are where people grow.

imafan26
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Posts: 11269
Joined: Tue Jan 01, 2013 1:32 pm
Location: hawaii, zone 12a 587 ft elev.

Re: Container Mix help needed

My cucumber in reused soil was looking "small". It had some mildew but was otherwise just smaller than it should be. I knew it had to be a nutrient or pH issue, but I did not want to have to do a soil test as it would cost more than getting new potting soil. I decided to take a chance and guess that I needed fast nitrogen and more phosphorus since my regular starting fertilizer was 6-4-6 with slow nitrogen and it was acidic. I used 1/4 cup of 10-20-20 and mixed it in the pot. Now, three weeks later the leaves are bigger, it is starting to grow longer and the cucumbers are starting to show up. I think I have finally found a way to make this work. I will have to repeat the experiment on the other pots before I can say it is a go, but it does look promising.
Happy gardening in Hawaii. Gardens are where people grow.

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