I have plenty of tires but not much dirt. Luckily my compost bin is overflowing
Rather than try to dig it out from the bottom I just took the bin off. It looked like moussaka with layers of leaves eggshells, wood shavings and compost at the bottom
I probably should have mixed the compost with some other stuff to make it drain better but the plants seem to be doing ok. Making good potting soil can be tricky and has it's own controversial issues. Perlite and vermiculite, which are used to provide good drainage and make the mix lighter, have to be mined in far away places. Even peat moss which gives potting soil it's light texture and ability to retain moisture is not considered sustainable. Then there's the whole issue of whether it's organic or not.
I like to think that I have all the resources on my property to make good soil but it just takes good management and planning. The litter I've been removing from the chicken coop should be a treasure trove of good nitrogen but can also contain a lot salt, so it needs to be cut with other organic material. Well aged leaf litter can provide the same service as peat moss but can take two years to mature. Every year I'm required to cut the wild grass on the hill at the beginning of fire season in May. I try to just chop it fine and let it lay where it falls as mulch, but I could also gather some of it to compost. I would just need to make sure that the pile reaches a high enough temperature to kill the grass seeds so they don't start growing in the new-made potting soil.
I've already put another tire on and the towers could probably use a couple more. I'm going to need to figure this dirt thing out pretty soon. I'm also hoping to put in other raised bed which will need lots more.
So far the chickens haven't been eating the potato plants. Supposedly chickens don't like the taste of potato leaves which I guess is a good thing since they're poisonous.
Update 4/5/11:
Another Tire
