Barriers can also be used to prevent diseases. For example, peach leaf curl is a devastating fungus that can simply be prevented by placing a barrier of polythene sheeting over a trained peach tree in the winter. This simple barrier prevents the spores splashing up onto the plant.

Slugs are most gardener's worst enemy. Barriers of anything sharp and gritty are supposed to protect your tender plants, as is bran (they're supposed to eat it and dehydrate). There are all sorts of products available for slug control on the organic market now. One that springs to mind is a band of copper that gives the slugs electric shocks.

If using a barrier method with slugs remember that success depends on you being extremely generous with the chosen deterrent.

Traps
Another popular method of protecting your plants is to use traps. This can be anything from beer traps for slugs (and yes, they really do work!) to codling moth traps hung from your apple trees. Sticky traps are very popular with the organic gardener.

A codling moth trap, for example, uses a pheromone placed on a sticky floor. The male moth is attracted to the trap thinking it is a female. On landing he gets stuck in the glue. There are similar traps for plum moths, too.

Greasebands, painted around the trunks of apple trees in autumn are a popular way of preventing the wingless female winter moth from climbing up the tree to mate. Sticky glue is also very useful for glasshouse staging if you have a problem with ants. Sticky yellow bits of card hung up in the glasshouse can help reduce the population of whitefly.

Beneficial insects
Beneficial insects and wildlife are really your best friends when it comes to controlling pests in your garden and vegetable patch. Planting simple annuals amongst your vegetables, such as Californian poppies and marigolds will attract a wealth of beneficial insects like ladybirds and hoverflies who will gobble up your aphids. Plant a few native shrubs and herbaceous perennials (ie hazel and hardy geraniums) in your garden; create a pond; leave a small pile of logs in the corner of your garden and feed the birds throughout the winter. Doing any or all of these will keep enough wildlife in your garden to eat thousands of pests and their eggs.