Vegetables typically require daily watering during summer weather, but may need a second watering when temperatures are extremely high.
As the weather heats up and plants reach full size, you may need to water containers (and especially hanging baskets) twice a day.
Even in the warmest days of summer, a good soak every three or four days is best for plants because it forces their roots deeper into the soil where they are healthier and cooler.
During extremely hot weather (daytime temperatures above 90F and nighttime temperatures above 70F), try to water daily or every other day. In a 10x10-foot garden, this would mean giving your plants 8 to 9 gallons of water each day.
Be Consistent
You should check the moisture level around the base of your plants. Determine the watering schedule you need to keep in order to maintain the right level of moisture. Watering every day or every two days doesn't matter nearly as much as consistent watering. Make a schedule and stick to it.
During really hot weather, water your vegetables at least two to three times a week. Watering the garden deeply is critical. The water must go down, down, down to encourage deep roots and get away from the hot soil surface.
But don't overwater
Plants sometimes wilt from the severe sun, even when they have sufficient water. Test the soil before you water, Young said. If a pot feels heavy or the soil feels damp an inch or so under the ground, your plant probably doesn't need more moisture.
It is ideal for watering your lawn about 1 inch of water for every single application per week. On average, it takes 30 minutes to disperse 0.5 inches of water. Therefore, you must water your lawn in hot weather three times per week, for about 30 minutes each, to get an inch of water on your lawn.
So, how hot IS too hot for plants? The general answer is around 90 degrees F, with some exceptions to the rule.
When working in the heat, drink 1 cup (8 ounces) of water every 15–20 minutes. This translates to ¾–1 quart (24–32 ounces) per hour. Drinking at shorter intervals is more effective than drinking large amounts infrequently. Do not drink more than 48 oz (1½ quarts) per hour!
If you forget or are too busy to water your plants on some summer mornings, you can water them at night. However, this should not be your ordinary watering time. Morning is the proper time for watering plants, though you should keep in mind that not all plants need daily watering.
Watering every day is not advised. It should be done 2 to 3 times per week only to prevent a shallow root system. If possible, water during the early morning hours to ensure that the lawn dries entirely before nightfall. However, watering at any time of the day is better than not watering at all.
One of the most frequently asked questions we get is how much water to use and how frequently do you water the plants. We recommend watering your plants twice daily -- early morning and late afternoon. To be more specific, early morning means 7-10am; and late afternoon means 3-5pm.
Watering container plants.
Pots absorb heat, which can stress plant roots, and the soil in them dries out much faster than soil in the ground. Container plants generally need to be watered daily. During really hot weather, you may need to even water twice a day, especially smaller containers.
Most plants shut down during extreme heat, so if it is over 100 degrees, it may be best to wait to water even if your plant is stressed.
Most lawn experts recommend watering your grass until the soil or ground temperature reaches the 40-degree Fahrenheit mark.
Avoid full sun
In the current hot breezy weather it is probably best to water in the early evening. This gives the plants enough time to dry out, but there is still the chance for overnight water uptake by the roots. And if you want to water in the morning then start very early – before the sun is shining.
Potted plants will probably want to be watered more than once a day during a heat wave. The next best time to water during hot weather is in the early evening. Trees and plants in or near irrigated grass yards will often want more frequent waterings as they can become spoiled and and often have shallower root systems.
Apply mulch, preferably a reflective mulch such as dry grass clippings. The first line of defense against hot weather and the windy conditions that can dry surface soil is to apply a liberal layer of mulch around the plants. This protects the soil from direct sun exposure, keeping it moist at the surface.
Watering late in the day in this heat and humidity increases opportunities for fungal diseases and visits by snails and slugs. Water in the early morning, period. Water plants deeply and not every day. Although it's labor-intensive, the best way to water during heat waves is by hand.
It is ideal to water lawns about one inch of water per week. To determine how long you need to water to get one inch, place a plastic container in your yard and set a timer. On average, it will take 30 minutes to get a half inch of water. So, 20 minutes, three times per week will give a lawn about an inch of water.