Life, as they say, is a series of compromises. I find traditional methods of composting challenging in a rental and incompatible with chronic pain. Instead, I trench compost in containers.
Necessity is the mother of invention. I would argue that composting is mandatory. It’s the one thing we can do to help our planet by nurturing our depleted soil and by preventing waste ending up in landfill. It’s also a big help when you are establishing an edible garden with very little income.
The problem is that traditional composting methods involve a degree of manual labour. This may make composting impossible if you have chronic pain. For several years I opted to have a worm farm as a compromise. This required minimal work but these have their limits and I was not making the most of all of my organic waste.
My container composting system is based on trench composting and my previous practice of bulking out large containers with cardboard to reduce the amount and cost of potting mix. I buy large pots as a cheap (and transportable between rentals) method of raised bed gardening. I discovered that the cardboard in these pots would break down and leave a very rich soil. I now combine the two systems and compost all of my organic waste not destined for the worm farm in containers. This requires no work at all and you are left with a portable pot of rich soil after your harvest. The only organics that do not go into the pots are very large woody items. I have a separate pile for these which eventually find their way into my no-dig garden beds.
The trick is in the choice of container. You need something very large, with massive holes, and with considerable depth. I use cheap large plastic pots from Bunnings to compost in but you don’t have to buy anything special. You want a pot that can accommodate a decent amount of compostable material with enough room to plant something on top of it all, and with excellent drainage to prevent your pot turning to sludge.
I have a pot always on the go near my back door to collect my organic material. I don’t hold back. Anything that can rot finds its way here unless it’s destined for my worm farm. I line the base with cardboard packaging and large paper items such as catalogues to which I add my daily compostables. I like to provide my worms with a balanced diet so, if I produce too much of something or something they wouldn’t like, it is diverted to my compost container. The possibilities are endless. On any given day you’ll find the contents of my vacuum cleaner, bits of cardboard, junk mail, coffee grounds, onion peelings, remnants of cotton cloths, shredded paper and plant clippings and anything else organic. When it is at least half full and has sat and settled for a bit I can prepare it for planting.
The next step is to add a few worms to your container. This is where it gets contentious. Many gardeners do not like to find worms in their pots as they can, amongst other things, inhibit drainage. Putting worms in your pots deliberately sounds like madness. But here’s the thing. Your worms won’t be degrading your potting mix or munching on the roots of your plants as they will be gorging themselves on that smorgasbord of compostables in the bottom of the pot. And, as they munch, they will be improving air circulation and breaking down nutrients. But, I hear you say, you’ve put all the stuff you won’t put in your worm farm. Yes, this is true, but I don’t use any pesticides in my garden and I welcome any critters that want to help break down my waste. And, even though worms aren’t keen on onion peels, there are very few of those to the amount of paper-based products and other critters take over where necessary.
Once you’ve added your worms fill the pot up to almost the brink with potting mix. I recycle my potting mix and I use what came out of the previous season’s pot (see below) or I use the cheapest potting mix available (usually around $3 for 25L) as the compostables and the worms will be feeding my plants. I’ve been expanding my garden recently and have had to buy several bags. I then place a watering pot in the middle to get my seedlings going before transplanting the plants and covering with a layer of mulch.
I also liquid feed my edibles with worm juice and/or wee depending on their nitrogen requirements.
This system is ideal for annual edibles. By the time your plants are ready to be harvested your pot will be fully composted and half its bulk. The following photographs shows how the soil level in the container gradually reduces as the waste is consumed:
At the end of the season you can rip out your spent plants (and put them in the current compost container) and use the rich worm-laden soil as either a starter for your next compost container or as a layer of your no-dig garden bed. The pot will be easy to carry around the garden to its destination and only requires a small trowel to scoop out the contents. Or, you can upend the pot to tip out the soil. This is your total manual labour for composting. The remaining labour is what you would normally do when planting in pots.