Although I subscribe to the principles of nature-friendly gardening, I'm not an organic gardener. I use chemicals and fertilisers, in moderation, when they present the best option.

I'm not the best person, then, to answer a question from a gardener who wants to know what kind of manures and fertilisers I would recommend to the serious organic gardener. I turned to John Harris, the author of Moon Gardening.

He describes how he uses seven different organic fertilisers, two kinds of animal manure and one vegetable manure. His choice of organic fertilisers is fish, blood and bone; sterilised bonemeal; dolomite limestone; gypsum; hoof and horn; calcified seaweed and seaweed meal. The animal manures are stable manure from horses, and farmyard manure which is the mixed product of all farm creatures with the exception of horses. The one vegetable manure is garden compost.

Fish, blood and bone is one of my own favourites, containing fast-acting nitrogen and also phosphates.

Sterilised bonemeal releases organic phosphates slowly and promotes strong root growth.

Dolomite limestone is used at 200g to 250g to the square metre to reduce the soil's acidity.

Gypsum improves the aeration and drainage of heavy clay soils and makes them easier to work.

Hoof and horn provides slow-acting nitrogen and is applied at 75g to 130g to the square metre.

John Harris swears by calcified seaweed for encouraging stone fruit such as plums. This is applied in winter at the rate of 115g to175g to the square metre and scattered around the trees.

Seaweed meal is used as a lawn food and as a general feed when applied to the surface of the soil.

All gardeners should read John Harris's book, Moon Gardening (Really Useful Books, £13.95).

By Jim Roberts