We get rid of weeds because they rob flowers and vegetables of the nourishment they need, compete for available light and air, harbour pests and often create humid conditions in which many diseases thrive.

Don’t be in a hurry to garden a badly weedy plot. Let it lie fallow for a year if you can, so that all the weeds that come up can be seen and dealt with before planting starts.

Weed any overgrown plot the easy way- plant a crop of potatoes. They will not only smother the weeds but "dig" the plot for you by turning over the soil. You do the rest when you harvest the potatoes.

The easiest and safest way to keep a clean plot weed-free is by constant hoeing- chop off the tops of weed seedlings and drag them out of the soil.

Don’t use a rotavator to "weed" a plot unless you use a weedkiller too. Digging the ground over this way chops up the roots of perennials like thistle and couch grass, making dozens of new young plants.

The most efficient- and dangerous weedkiller is sodium chlorate. Used on paths and drives it ensures that nothing will grow on them for at least a year. But it can creep sideways through the soil into flowerbeds with disastrous results. It is also highly inflammable when stored, so buy a version that contains a fire suppressant.

Use a mixture containing chlorpropham if you are plagued by annual weeds. It will sit on the soil and kill off any weed seedlings as they emerge. Don’t use it on sandy oil.

Weeds around trees and shrubs can be tackled with another very powerful herbicide containing fenuron.

Simazine is a useful total weedkiller which can be used on paths but will also kill off weeds around roses, soft fruits, shrubs or trees. It stays in the top two inches of soil and is effective for one growing season.

Paraquat is a useful contact weed killer which acts on the leaves of plants and kills them. It is very effective against annual weeds and grass, but perennial weeds will eventually re-grow as their roots survive. It is highly poisonous so use it with great care.

There are special hormone herbicides (MCPA and 2,4-d are the names to look for) which kill all weeds in established lawns without attacking the grass. They only work on broad-leaved plants.