If your plants are in the ground (versus a pot), the general rule is that plants need one inch of water per week. However, this does NOT mean watering one time per week. That doesn't usually do the job. Plants do best when watered deeply about three times a week, factoring in the rain.
Annuals, especially those purchased as flats, tend to need more frequent watering because their entire growth happens in only one short season. In the absence of rain, or in hot weather, they may need watering two to three times a week. Perennials, grow slower and should only need watering once a week.
Water as few times a week as necessary to fulfill your weekly water requirements without causing excessive runoff. Usually 1 or 2 times a week is sufficient. If you want to determine the maximum amount of time your sprinklers can be left on at one time, observe a cycle from the beginning to the time when runoff begins.
In general, houseplants' potting soil should be kept moist, but not wet. They normally need watering once or twice a week in the spring and summer, but less in the autumn and winter. However, depending on the type of houseplant, this is not always the case.
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.
A lot of plants can handle some neglect when it comes to folks forgetting to water. However, all plants need water to survive. Forgetting to water every now and then or watering a day or two later than you should can result in dead blooms and burnt foliage but these plants can survive that.
1. Succulents. These waxy, geometric beauties are certainly trendy, but not only because of their interesting shapes and hues ranging from mint green to deep violet. Their thick leaves store water, so they typically only require weekly watering (wait until the soil is dry before dousing them again).
Aloe. A spiky succulent with plump, toothed leaves, aloe (Aloe vera) is famous for its ability to soothe burns. These easy-care indoor plants don't need water very often, so you can let the soil dry out between waterings. Aloe grows slowly, like most succulents, but it will reach three feet tall and wide with patience.
Water Schedule for Cool vs.
Warm-season grasses require deeper and more infrequent watering (once or twice a week) than cool-season grasses. Warm-season grasses fare best when watered in the early morning before the sun becomes too hot.
Generally, light, daily or frequent irrigation keeps the top one to three inches of the soil moist, while deep, infrequent irrigation waits for signs of the grass wilting before applying enough irrigation to wet the soil to a depth of 10 inches or more.
Plants can be watered 1 to 2 times a week in seasons where there is a higher chance of rainfall and less evaporation. Avoid or reduce runoff by dividing irrigation into at least 2 sessions with a 20-minute interval in between sessions. This allows the water to filter into the soil.
The best way to tell if your plants need water is to stick your finger about an inch into the potting mix—if it feels dry, break out the watering can.
Insert a trowel into the soil, then tilt the trowel to check the moisture of garden plants. You can also insert a wooden dowel into the soil to determine the depth of soil moisture. If the dowel comes out clean, the soil is dry. Damp soil will cling to the dowel.
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.
Succulents and Cactii
As succulents and cacti are tough desert plants, they do well in dry soil. They're one of the best indoor plants that need water once a month.
When plants are not watered properly they wilt. This is because of something called turgor, which is water pressure inside the cells that make up the plant's skeleton. Water enters a plant through its stem and travels up to its leaves.
The best time to water plants is in the morning or evening.
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 best time to water is early in the morning when it's still cool, which preps the plants for a hot day, but that's not always easy to accomplish with a busy schedule. The second-best time is late in the afternoon or early evening.