Q How do I make comfrey tea?

A Comfrey tea is easy to make. Take any plastic container that has a lid, such as an old dustbin or bucket, and fill it to the top with freshly picked and shredded comfrey leaves. Then press them down as hard as you can. Fill up the rest of the container with water to around one part leaves to two parts water and put on the lid.
After four weeks, strain the resulting liquid from the decomposing plant remains. Dilute this liquid to about one part to 10 parts with water, and use for feeding fruit and vegetable crops. Remember that the concentration will vary, so don’t use homemade feed on small seedlings.

Comfrey is easy to grow and is a reasonably attractive plant with large hairy leaves and small pink-and-blue bell flowers. It’s a bit thuggish, though, and will need to be kept under control in your border, so would be better off grown in an allotment or wild corner of your garden.

Caption: You don't need special equipment to make comfrey tea

Q What nutrients does comfrey tea contain?

A In the Which? Gardening magazine trial, we found that both batches were very rich in potassium (K) and nitrogen (N) but had no phosphorus. This makes it great for encouraging flowering, fruiting and leaf growth, and ideal for a good crop of veg or fruit. It was also laced with trace minerals – useful if your soil is poor. The spring batch made with new leaves contained slightly more nitrogen.
WHICH? GARDENING MAGAZINE VERDICT Comfrey tea is easy to make but very smelly. It’s worth a try on your vegetable plot, especially on plants such as tomatoes that like high-potassium feeds.