Garden sprayers usually consist of a plastic canister with an attached spray hose. A hand-pump mechanism in the canister compresses the air to force the fluid out the hose. The hose has a sprayer with an on/off control and may also have an adjustable nozzle to spray in a stream or wide spray pattern. The sprayer is typically used to apply herbicides or pesticides to a lawn, garden or exterior of a house.
The capacity of a garden sprayer can be as little as three pints for a one-hand model up to four gallons for a backpack model. The capacity impacts how much the filled canister will weigh. A gallon of water weighs about eight pounds. You can partially fill a large-capacity garden sprayer to keep the weight in check, but it is more economical to buy a smaller-capacity model.
Use a garden sprayer on a non-windy day to avoid spray floating on the breeze and killing desirable plants or grass. Apply in the morning of a sunny day with no rain forecasted for at least 24 hours to avoid the chemical being washed away before it has time to do its job.
Adjust the sprayer nozzle to meet the requirements of the area being sprayed. Use a wide spray pattern to cover a large area, like the side of house, in a single sweep; use a pinpoint stream to fit into cracks or hit a single weed without disturbing plants in the vicinity. Walk backwards or sideways from where you spray so you do not walk through the chemical.
Wear protective clothing, including gloves, long sleeves and pants, to avoid getting chemicals on your skin. Label the garden sprayer to indicate what mixture is inside, like the brand name of the product or "weed killer." Once a chemical has been used in a garden sprayer, never use it for any other purpose.
Measure the chemical and water being used rather than guessing. Too much chemical costs you more to apply, and can harm the environment. Too little chemical can impact the effectiveness of the chemical.