What are the limits of planting directly into pre-compost material?

Question

I was wondering what the limits were to planting into organic pre-compost material.

As an experiment my father has grown a few things be simply planting them in a pile of used tea bags. This seems to work and teabags are amazingly swift become new compost if placed on the top of potted plants. (They also keep the moisture in the soil when it gets hot).

In an indoor only apartment what sort of limits can I run into by allowing any composting to take place while the material is already host to the plant(s)?

I want to make my own compost and use the compostable material my home generates which is why I asked about Indoor composting with limited space and have started to wonder about letting the growing roots of the plants do some of the work.

Obviously I do not want to risk disease to my plants or a bad smell to my home but cannot find much information online about using this approach.

Answer 1

Disease to plants and bad smells are both concerns. Additionally, nitrogen and possibly heat could become a problems.

The bacteria breaking down your compostable materials are much better at locking up nitrogen than the plants are, and if your inputs are low in nitrogen to begin with, the bacteria can starve the plants of nitrogen.

On the other hand, if your inputs are too high in nitrogen, heat could theoretically become a problem. Bacteria produce quite a bit of heat as they break down material. Bacterial activity, and the amount of heat produced, is often limited by nitrogen availability in the compost inputs. Users of cold-frames can keep the frames a bit warmer by adding some green compost inside, and compost piles can, in some circumstances, spontaneously combust due to this process. It is possible, at least theoretically, that you could literally cook your plant roots by adding too much uncomposted,high-nitrogen material to your plants or put plants in unfinished compost. High bacterial activity is also likely to be "stinky."

Of the two concerns, the heat would be the lesser in the case of indoor plants. The smaller containers should be able to shed any heat generated before it can build to troublesome levels.

It would be best to compost first, then plant. Or if you just have to add uncomposted materials to plants, to do so in limited quantities at any one time.

Answer 2

Another potential issue: Pre compost materials don't pack well. Sure teabags do, but consider corn husks, cabbage leaves, asparagus butts orange peels. They are too spacious for a good root system.

Living in an apartment, I'd suggest starting a vermiculture bin. (red wrigglers) The worms and the bacteria together do a much faster job. A pair of the 10" rubbermade totes work well for this with minor modifications: You need to make some air holes, but the air holes need to be screened to keep out fruit flies. You can duct tape scraps of screen or mosquito netting. a pair of 4 square inch openings is sufficient. These can be in either the base or the top.

From my experience two shallow ones work better than one deep one. With a deep one, the bottom tends to get soggy.

Having two also means you can move material between bins to mix it up.

Water is one of the breakdown products of the decomposition, so you will get water collecting in the bottom. Drain off and use to water your plants.

In a warm climate you can keep the worm bin on the patio or balcony. Once temps are getting below 50 F (10 C) The worms are unhappy when cold, or at least inactive.

Answer 3

Compost is spongy and easily compacted. Which is why it's a soil amendment and not a pure growing medium. Pre compost is still in it's decomposition stage so there's few soluable nutrients yet for the plant to grow but it's not uncommon for weeds to often spring up in compost piles