If I'm trying to manage my garden without outside inputs (with a minimum of them at least)- as a rule of thumb how much compost would I require? How much land to I need to put over the growing compostable crops rather than food-for-me crops?
I'm in a temperate climate in the UK, my 'garden' is an allotment plot of 50metres by 5metres. I don't own the plot (its rented) and it behind locked gates, its a few miles from where I live and I only have a bicycle! So... how to have enough organic matter? I can't really haul stuff in, I can't get people to drop things off (and waste laws are pretty strict here), buying compost is really expensive. Roughly.. from your experience (or reading, or even pulling numbers out of the air), how much of a plot should be put the growing 'compost' to supply enough? Strategies to need 'less'? Best things to grow to compost?
('enough'- enough for what? Say enough for pretty intensive no dig gardening? Any other qualified 'enough' is fine though. I'll be growing annual veg, and perennials such as berries and herbs)
I'm sure there was a book somewhere that had something along the lines of 'x% of your land should be put over to compostable/N-fixing crops'- but I forget the book.. or the numbers involved.
I can't give you the figure or ratio you're asking about specifically -- perhaps someone else will. But I think that given your limitations, you might also consider growing a tough and prolific green manure to help enrich the soil in addition to compost.
Buckwheat, for example, is easily available in the US at organic food stores -- it might be in the the UK, too. It's sold for sprouting and sprout it does. It also grows quickly and is very sensitive to cold (=easily frost-killed), and as long as you cut it down before it sets seed it will add a lot of organic matter. You might even look for some plants that will do double duty. It depends on the climate, of course, but I think in most of the UK peas and kale should grow well. Kale seed is cheap (and kale makes a lot of seed quickly, if you need to generate your own from a limited supply) and kale is prolific, and peas fix nitrogen and create a good amount of organic matter in short order, as well as producing tasty green spheres for the table.
Hau, Charli, Since you mention this is an allotment plot, behind locked gates it probably has been used for gardening already, yes?
It is preferable to use winter to grow greenmanure cover crops (nitrogen fixers) which are chopped and dropped in spring, then the seeds are sown through this.
If you want to grow food and compostable materials in this space, use 10 meters of the length to continually grow your greenmanure crops which will be chopped and composted all year long.
A good space size for the heap would be 2m square, that will allow for enough height to be developed for a good heat up for compost.
If you determine you don't need all of the remaining 40 m for food growing, you can then add more to the composting cover crops.
At any rate, each winter do a full space cover cropping so you aren't leaving soil bare, and you are growing materials for your compost pile and chop and drop mulching.
Bryant- it has been used for gardening before, and whilst the soil isn't dreadful and there is actual soil, its quite clayey and on a north facing hill that suffers a bit from erosion in the winter rains.
Its just I read about things like no-dig gardening where you need to add an inch of compost to all your beds every year.. and I think- how on earth do you end up with that much compost?
Eventually it will have lots of perennials in so I'll have a reduced need for compost! But the raspberries have only just been put in so it will be a while! I've acquired lots of buckwheat and alfalfa seed (thanks Chip!) so will try that on a permanent 10-metre or so compost-growing area.
I do no dig and have for years, I added compost for the first 3 years and after that I just chop and drop the leftovers from the growing season. Being in the "business and a chemist/biologist/horticulturist" I test my soils yearly. for the last two years, my gardens have been almost exactly where I want them nutrient wise and pH wise. I am crushing some minerals to add this coming winter to raise some of the trace elements. I have lots of Mycelium living in my soils, some naturally occurring, some I have intentionally added, the gardens really took off when I did the inoculations and now I just monitor how they are doing.
I have one new garden plot on the farm which we are double digging and amending so we can get the soil into better shape for planting. This area is getting biochar, mycelium, composted manures, mushroom compost and chopped wheat straw. We are also building three new growing mounds (hugels) with blow down from the tornado last year and the following wind storms. We are a practicing permaculture/mycoremediation organic homestead farm.
I really think you are on a great path with your plot. It sounds like you acquired a great piece of land to garden.
Chop and drop allows for replenishment of the soil with the left overs from what you grew, it gives back, through decomposition the things the plants took from it to grow.
The chop and drop acts at first like a mulch then becomes a top dressing compost. It will only get better year after year.