Chemicals: using safely and effectively

Plants often require protecting from pests, diseases and competitive weeds. Consider non-chemical solutions first, but if you do decide to use chemical controls, keep it to a minimal and highly targeted manner, following the product instructions accurately to ensure that people, pets and the wider environment are protected. Here we guide you through the general principals of keeping safe.

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Chemicals can be safely used in the garden by following a few common sense guidelines. Image: John Trentholm/RHS

Quick facts

Suitable for A wide range of pests, diseases and weeds
Timing Various, according to the problem
Difficulty Moderate

Suitable for...

Chemicals are best used when it is not possible to control the problem through other methods. There are products available for use for most pest, disease and weed problems that occur in the garden.

The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be only used in a minimal and highly targeted manner. For example, diseases or weeds pose a serious threat to the wider environment, to important heritage specimens, to habitat, or to native wildlife.

How to use chemicals safely

Use garden chemicals responsibly;

  • Always check labels for the ways in which a chemical (including fungicides, insecticides, herbicides or weedkillers, algae and mosskillers) can be used. Not only are these the most effective way of using the material, but adhering to these instructions is a legal requirement. If you read the instructions before purchase, you can also be sure you do not buy more than you need; many chemicals have a short shelf-life and are best not kept from year to year
  • Safety details will also be on the label. When used as directed, the chemicals sold to gardeners are benign to the environment, pets and children. However, it is important to use garden chemicals responsibly
  • Rubber boots, old clothes or overalls and gloves, although not usually strictly necessary, are a sensible precaution
  • Be particularly careful to thoroughly rinse out old containers before discarding in the refuse

Watering can or sprayer

  • Sprayers or watering cans may be used but sprayers apply chemicals more economically and accurately
  • Have a dedicated sprayer for weedkillers and another for other materials
  • They should be checked for leaks and blockages using clean water before use
  • Where a measured amount of material is to be applied to a given area the output of the sprayer should be checked first using water alone

Concentrates or ‘ready-to-use’

For small scale jobs consider ready-to-use packs. In many cases the nozzle design on these is really only adequate for treating a small area though some now have pump action and can be used on larger areas. There is an extremely low risk to gardeners from diluted chemicals, and the slight hazard of garden chemicals comes mainly from the concentrate.

For garden chemicals and other plant protection products currently available to gardeners see:

Applying chemicals

When using a spray, consider the following;

  • Apply the chemical using a spray sufficiently coarse not to drift but fine enough to cover the plants’ foliage evenly
  • Apply the chemical up to the given dosage per unit area or sufficient to wet foliage without run-off. Never apply chemicals on a windy day
  • After spraying, rinse the sprayer with three washes of a small amount of water, spraying this out onto areas, plants or weeds listed on the label. The sprayer will then be safe to store

Safeguarding children and the environment

As well as measures to protect the operator and nearby plants, gardeners using chemicals are responsible for protecting children, wildlife and the avoiding pollution of the wider environment.

  • Exclude pets and children from treated areas until the spray has dried
  • Do not spray open blooms because of the danger to bees, butterflies and other flower visitors (pollinators)
  • Contamination of water must be avoided. Fish and other wildlife in ponds, ditches, streams etc, are very susceptible to pesticides. High risk activities include flushing surplus pesticide down toilets or drains, applying weedkillers to hard surfaces where run off might enter drains and emptying pesticides on to the soil to dispose of them

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