Potting Soil Recycling

Since I live in an urban area, managing potting soil used for growing vegetables means recycling it in the most efficient way for re-use. My garden consists of eight 3 gallon pots and eight 5 gallon buckets for a total of 64 gallons of volume, which is about 8.5 cubic feet.

After a year of hosting plants the soil is rather compact and on the verge of acting like clay, so to fluff it up I use coconut coir as it is a much more renewable resource than peat and readily available. I like the brand Beats Peat because each bale can be easily separated into 4 layers and a single layer is almost 1500 grams so it is perfect for the recipe. You have to soak this in a good amount of water until it is fully rehydrated, and it can take some time. The dense compaction of fiber is prohibitive to easy rehydration, so I usually break it up and scrape off the moist parts to speed things along.

I also add a good amount of worm castings to put back some nutrients into the soil, along with azomite which is full of trace minerals and humic acid which is a natural plant growth stimulant. Since some of this can be hard to find or transport in the city, I just get it off Amazon. My preferred products are linked below.

To mix, I have a large plastic storage container where the coconut coir is prepped and then the old soil is mixed in while removing the old root balls and large root chunks, then the lime, azomite and humic acid is sprinkled evenly over the soil and then mixed in – using a dust mask for these as they are very fine particles and not something you want to inhale. After things are mixed I usually let it rest for a few days to mix it again after the moisture has evened out, and then refill the buckets, and put the excess into a heavy duty, double layered garbage bag  for storage.

Since it is time consuming and labor intensive I have been doing this over the last several months and have almost finished the complete set.

Here is my recipe (in grams) for remixing the soil:

2 gallons old soil 3 gallons 5 gallons 8 gallons
2gal coconut coir
(600g)
900 1500 2400
1gal worm castings 450 750 1200
1c lime 495 825 1320
.25c epsom salt 78 130 208
.25c azomite 85.5 142.5 228
1tbsp humic acid 1.33 tbsp 2.33 tbsp 3.66 tbsp

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