Knowing how to water plants properly may be a top priority for any plant owner. It's important to understand the watering process and how often to water your plants, as you can overwater or underwater your plants. While some plants don't require sunlight and some are basically self-sustaining, all plants need water.
Every plant is different, and every environment is different. The same plant will need more water if placed in a sunny spot than if placed in a shady spot. Older, larger plants may need more water than smaller, newer ones. Care must be taken to ensure watering is adequate. To elaborate on the best way to water your plants, here are some rules that expert gardeners follow when caring for indoor or outdoor plants.
Check the weather
The amount of water your plants need varies with the season. Plants usually need less water in winter because the days are shorter and plants are dormant. In mild weather (especially in spring), plan to water potted plants once a week.
As temperatures rise in late spring and summer, plants need more water because the heat evaporates the water before the plant can use it. You may have to water your plants several times a week, or even every day.
Adjust the water level
The size of your plant determines how much water it needs. Larger plants need more water and smaller plants need less water. Customize water levels to suit your plants.
Additionally, larger pots with smaller plants will hold more moisture, so adjust water accordingly: small pots and hanging plants will need to be watered twice a day, while larger pots only need to be watered once a day.
Drink water in the morning and evening
Whether you water your plants once a week, daily, or even twice a day, it's best to water them in the morning or evening. This is especially true for outdoor plants, as it helps prevent water loss through evaporation.
Watering in the morning allows the water to penetrate the roots before the sun comes up because the soil is cool in the morning. The same is true for watering in the late evening.
Avoid overwatering
Plants love water, but overwatering can actually be harmful. Fill the pot with water until it seeps through the drainage holes in the bottom. (If your pot doesn't have drainage holes, you'll need to take precautions like placing rocks or another moisture trap in the bottom to prevent root rot.) This way, the soil and roots know they have access to moisture throughout the pot.
Add only enough water so that it runs out the bottom, but not soggy. If you try to water your plant again later and the surface of the soil is moist, you probably don't need to water it yet.
Water the soil, not the plant
We often talk about “watering your plants,” but it's important to water the base of the plant (i.e. the soil), not the plant itself. Water should be poured into the soil, not on the leaves or flowers. This way, water gets to where it's needed – the roots. Overwatering plants can also lead to fungal diseases and scorched leaves.
Water your houseplants with room temperature water
Water that is too cold or hot can damage a plant's roots. Water that is too cold or hot can also “shock” a plant, causing it to wilt or die. The ideal water temperature for plants is about 68 degrees Fahrenheit, but keeping it between 59 and 77 degrees Fahrenheit should be fine. Outdoor plants are generally not too finicky, but if you do water them with a hose on a hot day, run the water for a few minutes before holding the hose on the plant to prevent it from boiling.
Keep the pot dry
It may seem counterintuitive, but keeping the bottom of the pot dry is important for the health of your plant. Leaving the pot submerged in water (or watering it frequently) can cause your plant to develop root rot or even die. If you use a saucer under your planter to collect water and soil, be sure to empty the saucer after watering or after it rains to keep the roots and soil from getting soaked.
Trim dying plants immediately
Keep a close eye on your plants. If they start to wilt or droop, it may be time to water them. But inspect the soil first. Wilting and drooping doesn't necessarily mean the plant needs water. It could be a sign of overwatering, a light problem, a temperature problem, or that the plant has outgrown its pot.
Give it plenty of water
If you have a choice between watering shallow and frequent or watering deep and frequent, always choose to water deep and frequent. Remember that water needs to penetrate through the soil and into the roots for the plant to benefit. Plant roots aren't near the surface, so watering deep gets the water to the roots.
Thorough watering also benefits plants because it “trains” them to develop roots deeper in the soil. Plants with roots closer to the surface are less able to tolerate dry conditions, while deep-rooted plants can better tolerate drought. For new plants and trees, thorough watering helps the plant develop and become established.
The difference between overwatering and too much water is subtle. Overwatering occurs when the soil is constantly saturated, resulting from watering too frequently. Plant roots need a delicate balance of moisture and oxygen to stay healthy, but overwatering can prevent the roots from getting oxygen.
To avoid overwatering, allow the soil to dry slightly between watering (but don't let it dry out completely). If you notice pooling of water around the plant and not draining or absorbing it, it's likely overwatered and you should cut back on watering. Signs of overwatering include brown or yellow leaves and grey, slimy roots (a sign of root rot).
Remember that young plants need more water.
Plants that are less than a year old in your home or garden need more water than more mature plants. Water these plants more frequently, but be careful not to overwater them. The same rule applies to seedlings. Seedlings need even more water than young plants, up to twice a day.