HDRA Encyclopedia of Organic Gardening (£25) 
 
The recently published Encyclopedia of Organic Gardening, produced in association with the Henry Doubleday Research Association, is likely to become a best seller.

Organic gardening can lead to 'healthy eating', 'healthy gardening', 'healthy wildlife' a 'healthy environment' and a 'healthy future'. Isn't that why we all like the idea? And who better to guide us through a book on organic gardening, the HDRA way, than Editor-in-chief Pauline Pears and her team of writers? Pauline is well known in the gardening world for her knowledge of organic methods of horticulture.

In the Encyclopedia, there is a wealth of information on general cultivation that would be appropriate in any book on gardening: for example, raising plants, sowing seeds, design, growing herbs etc. But I suspect the book will be bought mostly for its comprehensive pest and disease control sections, and 'HDRA Organic Guidelines' - especially by people who are unsure over exactly which are the approved methods. Although chapters on natural predators; water conservation; weed control, mulches and techniques; plants for wildlife; compost-making, and worm composting, all make fascinating reading.

The HDRA Encyclopedia of Organic Gardening is a basic guide that covers most aspects of the subject, while addressing some of the controversial issues: the genetic modification of plants, biological pest control, and the use of the word 'organic' in retailing.

What is "organic"?

Today it is illegal to sell food as organic produce unless it carries a recognised organic symbol. But there is an on-going debate over what exactly should, or should not, be called organic in the product retailing industry. Apparently certain manure products have been labelled "organic" simply because they are of living origin. However, they wouldn't all be recommended by HDRA for use in an organic garden.

Biological pest control - the use of microscopic pest predators is described in the Plant Health section. For slugs and vine weevils, the section's author, Dr Martin Warnes, recommends parasitic nematodes (Phasmarhabditis hermaphrodita and Heterorhabditis
megidis respectively). A list of other common pests and their predatory or parasitic killers is given, with notes on their special temperature and humidity requirements.

There is general disapproval in the book for genetically modified organisms (GMOs), described as the antitheses of organic growing - although there is a careful explanation of genetic engineering with cautious reassurance for the reader. The reason given why 'GM plants and animals are not organically acceptable' is because opinion is still divided over whether the technology is considered safe for human health and the environment.

Rabbits - Country gardeners often suffer from the damage done by rabbits to precious plants. The following preventative measures are recommended in the encyclopedia. A rabbit-proof fence, with size 2.5 to 3cm mesh and 1 -1.2m high, can be erected around valuable plants. It should also be buried 30cm below ground level; otherwise rabbits may try to dig their way into the garden. The following plants are unattractive to rabbits in all but the harshest winters: azalea, buddleja, choisya, clematis, daphne, euphorbia, hydrangea, and rhododendron. A full list is given in the Encyclopedia.

Fascinating facts

There are thousands of facts in the book that will instruct gardeners. Under heading 'Weed control in lawns' comes 'Clover will also help to feed the grass' and (unsurprisingly to many) not recommended are 'All chemical fertilisers and pesticides'. Other helpful tips include how to make homemade liquid plant feeds from nettle leaves. And amazingly - to me at least - up to 15,000 caterpillars will be collected by one pair of bluetits to raise their brood.

We learn that the organic gardening movement is beginning to influence the choice of hard materials for the framework of gardens. The widespread use of concrete, tarmac, paving and polythene limits the amount of fertile land available for cultivating plants; and some of the materials can contain toxic elements. Timber is recommended in the book as an environmentally friendly material.

Froglife - charity for frogs

In the useful Resources section, there is even a note on a charity for frogs - an organisation devoted to the conservation of reptiles and amphibians. For the free helpline; pond doctors, email froglife@froglife.org

This fully illustrated reference encyclopedia provides the reader with information on organic gardening in a form that can easily be understood. An A-Z of vegetables explains how to grow over 80 crops organically. Here is a book every gardener should read. It will appeal to experts and beginners alike.

Ed. Pauline Pears, HDRA Encyclopedia of Organic Gardening, Dorling Kindersley, 2001. 416 pages.