Lay a soaker hose along the base of plants to water gradually without waste.
You don't have to worry about pots drying out if they have drip irrigation. An emitter delivers water one drop at a time to keep the soil consistently moist.
Use a distributor to section off parts of the garden so that you can water them independently of each other. The distributor allows you to control the flow to whichever hose you choose.
A water timer can be simple like this dial type, or more elaborate with programmable features that can turn water on and off over a week or longer.
Mulching keeps moisture in the ground by helping prevent evaporation.
Rain barrels are increasingly popular as a way to collect rain water to use in the garden later.All these things add up to great water savings that can keep your garden going in dry times. Remember that vegetables are about 90% water. No water, no harvest!
Soaker hoses put water where you want it. Lay out a soaker hose alongside rows or through beds to deliver water gradually without waste. Soaker hoses can be damaged by sun, so cover them with a layer of mulch. Also keep in mind that soaker hoses are more efficient than overhead sprinkling but not quite as efficient as drip irrigation (next item below). In the winter, take up your hose and protect it from freezing weather, again to avoid damaging the material. Sounds odd, but the soaker could spring a leak; then too much water might ooze out in one place and keep it from moving through the entire length of the hose.
Try drip irrigation. This is a little more trouble because tubes are run to every plant, but it works great in small gardens and pots. The tubes and emitters deliver water to the base of plants where you place them and nowhere else. Drip irrigation was perfected for agriculture in the desert climate of Israel where every drop counts. It is most efficient.
Water in sections. Some parts of the garden may get thirstier than others depending on the soil, amount of sun, and how the crop grows. For example, deeply planted tomatoes (two-thirds under ground per Bonnie instructions) may have access to deep soil moisture while the pole beans are hurting. In this case, it helps to water the garden in sections, connecting more than one soaker hose to a distributor that provides adjustable outlets off one faucet. This lets you turn on one section and turn off another. Most soaker hoses and drip systems are sold in varying lengths.
Water deeply. Let water get way down into the soil. Frequent, shallow watering is tempting, but it’s not good. It encourages roots to stay near the surface and makes plants more susceptible to drought. It is better to water plenty (which means deeply) once or twice a week than to water a little every day. By deep watering we mean applying at least an inch of water at a time. You can measure this by placing a container where it can catch the water. When it is filled to an inch, you’ve applied enough.
Standing in place while you water with the hose, although tempting, is not usually a way to water deeply. Time or patience usually run out and water runs off. Use soaker hoses, drip, or sprinklers.
Mulch around plants. A 2- to 3-inch layer of straw or other mulch around your plants helps keep the soil moist longer as a barrier between the moist soil and the drying effects of sun and hot air. The mulch helps keep weed seeds from sprouting. You can mulch with straw, pine straw, homemade compost, or even sheets of newspaper (4 sheets thick).
Use a timer. A timer on your spigot will turn off the flow without depending on your memory or schedule. You can buy these at garden centers and home improvement stores at prices starting about $20. They’re worth every penny as they make it easy to have a garden and a job, too!
For the long term, improve the soil. Add lots of compost to improve soil texture. Heavy clay can hold lots of water, but it really does get as hard as a brick when it dries. So compost makes it easier on plants in heavy soil. It also helps sandy soil, which absolutely does not hold water. Sand is tiny grains of rock impervious to water, so adding compost, which sponges up moisture, increases the ability of a sandy soil to hold water from the hose or the heavens. If you don’t have a compost pile going, it is never too late to start one. You can also buy bagged mushroom compost (a byproduct of mushroom farms) that makes a good soil additive.
Collect water in rain barrels. You can buy official rain barrels with spouts or you can fashion your own from many types of barrels or large containers. Use these to collect water from gutter downspouts or other areas where water runs and is easily collected. Save this for a not so “rainy day.” Just be sure that whatever container you use can’t be reached by small children and won’t be used by mosquitoes to lay eggs. Screening over the opening keeps mosquitoes and litter out.