Water your plants in the morning as early as possible. This allows the soil and your plants to absorb more water because in the heat of the day there is more evaporation occurring at the soil surface. Drip irrigation is ideal because it deposits water directly at the soil surface and can be targeted.
Watering in the heat of the day shouldn't hurt the plants -- it actually cools them off -- but it's a far less efficient use of water as much of it will evaporate before reaching the roots. Avoid getting plants wet late in the day unless it's the only possible time you can water them.
If you water in the afternoon, especially during summer, the heat and sun are at their peak and the plant's water will evaporate instead of absorbing into the soil and roots. Morning watering is actually preferable to evening watering as the plant has time to dry before the sun goes down.
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.
If it's 70-80 degrees outside try watering 2-3 times a week. During the spring your lawn will be fairly easy to manage so you don't have to water all the time. In the blazing summer, when temperatures are between 90-100+, try watering 3-4 times a week.
The colder weather does not evaporate moisture from the lawn as quickly as it does in the warmer weather. Most lawn experts recommend watering your grass until the soil or ground temperature reaches the 40-degree Fahrenheit mark. It is true, less water is required and needed when the temperature drops.
As the weather heats up and plants reach full size, you may need to water containers (and especially hanging baskets) twice a day.
Early morning (5:00 to 9:00 am) is the best time to water the garden when using a sprinkler, garden hose, or any other device that wets the plant foliage. When watering is completed, the plant foliage dries quickly. The rapid drying of plant foliage helps guard against the development of fungal diseases.
Plants should be watered after 6 p.m. and before sunset, giving any damp leaves a chance to dry. Early morning as the sun rises also works well, keeping the spores in check.
In hot weather you need to water in the mornings when it is cooler. This will allow more water to reach the root system before it evaporates in the heat. There may be times when you cannot schedule watering in the morning. In this case, water the plants in the late evening before bed.
But there is no doubt that watering in full sun is not water efficient – as much of it will evaporate before entering the soil. In the current hot breezy weather it is probably best to water in the early evening.
Mulch, mulch, and mulch some more!
Cover your soil with a blanket of organic material such as straw, leaves, shredded paper or cardboard, or bark. This will moderate soil temperature, prevent runoff and evaporation, and hold moisture in the for longer periods between waterings.
If the soil feels dry, it's time to water. In the spring and fall and in cooler climates, it might be sufficient to water container plants every two to three days. In the summer and in warm climates, container plants usually require daily watering, unless they are succulents or other drought-tolerant xeriscape plants.
Leaf scorch is caused by failure of the tree to supply enough water to the leaves at a critical time, usually in July and August. A great amount of water evaporates from the leaf surface because of sun and wind during hot, dry weather. If the water supply is deficient, the exposed leaves dry out and scorch.
1) Plants are sensitive to temperature changes
The reason why we recommend early morning, between the times of 7am and 10am, is the temperature is not yet too hot. Personally, I water the plants I'm growing at home immediately after I wake up.
The ideal time to water them is in the morning before 10 am. 6 am would be good; 3 am is a bit early but also okay. The worst time to water is between 10 am and 2 pm, when the sun is hottest. Late afternoon through around 6 pm, or even later in the summer when days are long, is okay.
For most plants, watering in the morning or evening is best. Getting water on leaves will not cause burning. It can abet fungal diseases in some plants (roses, squashes), so watering most plants in the morning is ideal..
Higher temperatures cause the plant cells which control the openings (stoma) where water is released to the atmosphere to open, whereas colder temperatures cause the openings to close. Wind & air movement: Increased movement of the air around a plant will result in a higher transpiration rate.
There's no cut-and-dry definition of a deep watering. Most gardeners generally refer to it as when water has soaked at least eight inches into the soil. This gives plants the structure required to survive lack of water, whether from a drought, a busy gardener, or other environmental stresses.
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.
Check the leaves for wilting and test the top inch of soil with your finger to see if it's dry enough to need a drink. Test Garden Tip: You're more likely to overwater indoor plants than underwater. Too much water will drown your plants. A good rule of thumb is to let the top inch of the soil dry out between waterings.
Avoid watering grass on a hot afternoon when it's 95 degrees or higher. The best time to water grass is at dawn or in the early evening. Water deeply three times a week instead of a little water daily.