At its simplest, compost tea is what you get if you soak a porous bag of compost in a bucket of water for a while. If you do this, some of the nutrients that started out in the compost end up in the water, so you have a liquid fertiliser. No problem there – compost tea works just as well as any other fertiliser. But the claims for compost tea go well beyond that. Compost tea is also, of course, full of microorganisms, and these could be good for your garden and your plants. Thus compost tea is not simply like the liquid fertiliser made by soaking comfrey or nettles in water – it’s more complicated than that.