Does homemade fertiliser keep?
Q I made loads of seaweed/comfrey and nettle plant food this year and I’ve still got five big bottles left. Will it be OK to use them next year? James Couling, Portsmouth, Hants
A Homemade feeds are a great way of feeding plants, and are rich in nutrients. Comfrey is rich in potassium and also contains nitrogen and Vitamin B12, which gives plants a boost.
Nettles have a high nitrogen content, so are great for feeding leafy greens. You can also mix them with comfrey to create a balanced liquid feed.
Store them somewhere cool and dry and they should keep for up to a year, after which they may lose potency. They won’t harm plants, but will be less effective – you can always pour them on to the compost heap so nothing is wasted!
If you want to make comfrey tea, use the variety ‘Bocking 14’, a sterile, Russian variety that won’t self-seed everywhere, unlike the prolific common comfrey (Symphytum officinale).