There has been a widespread surge of interest in organic gardening over the last few years, as the idea of using as few manufactured chemicals as possible is something that appeals to many gardeners. The broad philosophy behind organic gardening is to take a holistic view of gardening. This means:

• Striving to conserve natural resources.
• Understanding the interdependence of all life forms in your garden.
• Avoiding pollution and health hazards.
• Establishing a balanced ecological habitat for plants, animals and humans.

Organic control uses natural methods to help plants both resist and recover from attack by pests and diseases, and can be achieved in a number of ways.

1. Disease-Resistant Plants

Some cultivars are specifically bred to resist certain pests or diseases; for example, there are lettuce cultivars that can resist lettuce root aphid and roses that can offer good resistance to diseases such as powdery mildew, rust and black spot. Before buying plants, check if there are disease- or pest-resistant cultivars readily available.

2. Plant Health

As described earlier in this section, keeping your plants healthy can prevent a whole host of infections and infestations. Grow seedlings on in pots so that they may be protected whilst at their most vulnerable, and make sure that only healthy, vigorous stock is planted out.

Maintaining a good spacing between plants will allow them to grow without overcrowding, and will also help to prevent fungal diseases.

Check plants regularly for signs of problems; a well-established infestation or infection is much more difficult to deal with than one that is identified and treated early.

3. Mulching

The addition of moisture-retaining mulches can help to keep powdery mildew from crops and ornamentals.

4. Companion Planting

Positioning certain plants together can help to reduce pest and disease attack. This is especially true of herbs, whose strong scents can repel pests, or attract them away from more important planting. They can also attract beneficial insects that will act as natural predators. For example, chives, fennel and oregano all repel aphids, whilst coriander and mint attract natural insect predators. Our guide to companion planting includes more information about planting to prevent pest damage.

5. Garden Hygiene

In our section on prevention of pests and diseases, we looked at how maintaining a tidy and well-managed garden can be one of the strongest weapons in the war against plant problems. Regularly removing and burning any infested or diseased plants or material will help to reduce the risk of the problem spreading, whilst destroying or composting garden waste will prevent it from becoming a refuge for pests.

6. Crop Rotation

Growing the same crop or plant in one area for a number of years can lead to a build up of soil-borne pests and diseases specific to that plant. This may be alleviated by rotating the crops and growing other botanically unrelated plants that are not susceptible on the site. Although crop rotation is most often carried out in the vegetable garden, it may also be used for annuals, bulbs and other plants. More details on crop rotation techniques used in the vegetable garden may be found here ...

7. Organic Treatment

There are some chemical treatments that derive from natural sources, such as derris dust, soft soap, sulphur dust and pyrethrum (from the pyrethrum daisy). Although they are safe to use, they only act on contact with the disease or pest, so regular applications are needed.

8. Organic Traps

Traps may be easily put together to catch a wide range of pests:

• Trap earwigs in inverted flower pots
• Attract wireworms to cut potatoes or carrot buried 10-15 cm (4-6 in) deep
• Use beer traps to catch slugs
• Attract greenhouse whitefly to a yellow card smeared with grease