There is usually no "worst time" to water your houseplants (or outdoor plants). If your plant needs water, it needs water. It's absolutely fine to water your plants at night, and in some cases, it could actually be a good thing.
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.
Morning watering is actually preferable to evening watering as the plant has time to dry before the sun goes down. At night, water tends to rest in the soil, around the roots, and on the foliage, which encourages rot, fungal growth, and insects.
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.
The best time to water your garden in summer is from 6 am to 10 am—before the heat of the day sets in, giving your plants plenty of time to drink up and any moisture on the leaves to dry off before nightfall. What is this? If watering in the morning isn't possible, the next best time is from 4 pm to 7 pm.
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.
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.
Watering in the evening with a sprinkler or garden hose can lead to greater disease problems as the plant foliage will likely remain wet throughout the night. Mornings and evenings are excellent times to water gardens when using a drip irrigation system or soaker hose.
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.
As the weather heats up and plants reach full size, you may need to water containers (and especially hanging baskets) twice a day.
Plants loose water at significant rates during the night through 'night-time transpiration'. Night-time transpirational water loss is most likely the consequence of having respiratory CO2 escape at sufficiently high rates through stomata.
Watering indoor and outdoor potted plants at night can increase the chances of root rot. Even a little water left in mulch or soil consistently can damage the root systems, which can cause the plant to struggle to grow.
Larger plants might need a few hours, whereas small plants in smaller pots will take considerably less time. Some people even bottom water their plants overnight. I prefer not to, because I like to check in on the moisture level and if the bowl needs to be refilled mid-way through.
When the weather is as hot as it is right now, you really should be watering your lawn every day if you can. However, there are watering restrictions in place for some of the area, so simply water as often as you can.
A: I assume your question is about the commonly held notion that full sun on droplets of water will burn the plant. The answer is no, to that question and to yours. (See The Myth of Hot-Weather Watering.) Even so, the best plan is to have plants well hydrated before the heat hits.
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.
Wetting leaves.
Plants get their moisture through their roots, not their leaves. Direct watering to the soil surface and avoid wetting leaves because water helps spread some plant diseases. Use a watering wand to reach ground level or a soaker hose or trickle irrigation system to wet the soil rather than the leaves.
Water Young Plants and Flowers Daily Until Established
Most young varieties call for daily watering (skip rainy days) until roots are developed, which happens around the two week mark. At that point, you can taper off and move to a weekly schedule if the variety allows.
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.
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.
watering plants around noon on a sunny day should be avoided, since it might harm their leaves. The explanation is that tiny water droplets can act like lenses, focusing the sun's rays onto sections of leaves just like a magnifying glass would, resulting in scorched foliage and reduced plant health.
Q. How often should plants be watered? Water once or twice per week, using enough water to moisten the soil to a depth of about 6 inches each time.
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.
Most plants grow best in temperatures ranging from 59°–86°F. When temperatures above 90°F are sustained for long periods, plant growth is slowed, and some plants begin to show signs of stress.
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.