The best time to water outdoor plants is in the morning when temperatures are usually cooler. This gives the plants time to absorb the water so they can get through a long, hot day. The second-best time is late in the afternoon or early in the evening. Try not to water at night.
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.
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.
The best time to water plants is in the morning or evening.
More importantly, watering at these times actually helps the plant retain water. 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.
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.
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.
By regularly spraying your houseplants with water, you raise the humidity around their leaves, keeping delicate species from the tropical regions of the world happy in distinctly untropical homes.
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. Throw a damp sheet over it, or mist it lightly to bring the temperature down.
And most importantly, plants absorb water more readily when they're not under heat stress—a condition that's more likely to occur when the sun is at its peak. So while it's perfectly okay to water plants while they're in full mid-day sun, it's not the most efficient way to go about it.
As the weather heats up and plants reach full size, you may need to water containers (and especially hanging baskets) twice a day. When you water containers (or plants in the ground), check that the soil is actually dry before you water.
Avoid watering when temperatures are below 40°F or when sustained freezing temperatures are expected within 24 hours as this water will freeze and not be available to the plants.
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.
We should water the roots so that the plant grows healthy.
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.
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.
The books are right – planting in the summer when it is hot and dry is not the best time to move new plants into or around the garden. During a particularly bad heat wave it can be hard enough to keep the soil hydrated, let alone provide ample moisture for plants that are establishing new roots.
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.
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.
If you are unsure how long to water new plants, aim for 30-60 seconds for small plants – longer for larger plants while moving the hose to a few locations around the plant. Avoid watering when the soil feels moist. The earth must be allowed to dry out between watering.
To keep them cool, use old screens, lattice and sheets to shade vulnerable mature plants from the effects of mid-summer sun. Cover new seedlings with opaque covers to protect them from the sun until their roots are established. Commercial growers often use sprinkling to cool plants down.
Misting creates humidity, and some tropical plants appreciate it (though there are more effective methods for increasing humidity around your plants), but it should supplement watering. To water properly, pour water directly on the soil until it runs out the drainage holes at the bottom of the pot.
“Spritzing your plants is not the correct way to water your plants. In fact, it doesn't water them at all,” she says. While spritzing can provide some moisture, unless the plant really thrives in humidity (ferns, orchids, or bromeliads, for example), Hovis says spritzing can do more harm than good.
Frequent misting is thought to help to boost the humidity around your plants, which is something that moisture-loving varieties can really appreciate. So, if you have dry air in your home, it is a good idea to mist regularly to help counterbalance this.