Friday, 29 April 2016
Comfrey organic compost experiment
I'm a fan of Comfrey as a mineral mine (especially potassium) for organic growers, but the standard advice to delay your potato planting until the first cut of Comfrey is ready (typically about 5% of the annual crop) makes little sense. So I experimented:
Last years' compost bin had 1 bale of wetted straw, a year's growth of Comfrey from 10 plants (about 200 lb), and approximately 200 lb of lawn mowings. The straw was absorbent enough to prevent liquid from decomposing Comfrey wasting as run off, and the lawn mowings generated enough heat to promote rapid composting.
This Spring I had plenty of this compost for 150 seed potatoes (equal amounts of first earlies, 2nd earlies and maincrop), and the compost appeared well made when I lay it in trenches prior to planting the seed potatoes.
The heap was always kept rainproof and there is no evidence that nutrient-rich liquids were draining away.
By July I'll be able to see how well this has worked.
This isn't a solution for everyone. Very sandy soils are hopeless for growing comfrey and similar deep-rooted mineral mines. Potassium is the least environmentally damaging of the NPK that 'conventional' farmers dump on their soil, but if you must resort to adding potassium (potassium sulphate is the best choice) then rather than adding it to the soil, add it to your compost heap - and keep the rain out!
The results 26th May, after the coldest April for years:
compost, environment, fertility, gardens, organic, soil