Overwatering and underwatering are the most common reasons people kill their houseplants. Knowing how, when, and how much to water your houseplants is a huge part of cultivating your green thumb and keeping your houseplants strong and healthy. It’s important to recognize the difference between water and soil moisture levels. Many houseplants need water to help unlock the nutrients in the potting soil, but they also need air. Waterlogged soil can lead to root rot by cutting off access to air and suffocating the plant. Even when placed in a pot with drainage, very few houseplants like to be watered every day or even every other day. By the same token, misting your houseplants can help with dry air, but it’s not a substitute for watering and unlocking the nutrients in the soil.
Learn about the tips and tricks we use to help us recognize how, when, and how much to water your houseplants. (You can also check out our general Houseplant Care Guide for other aspects of plant care including light exposure, soil, pots, and more.)
When to Water Your Houseplants
First, know what signs, if any, that houseplant has when it’s received too much or too little water. Some plants, for example, have leaves that will droop or wrinkle when underwater. Some plants will have leaves that go translucent or bloated when full of water. Discoloration and withered growth are the most common signs that excess water has caused root rot to set in.
As a starting point, you should also learn what your type of houseplant typically likes for watering frequency. A lot of succulents and other drought-resistant plants may like water once a month—or even less. Some plants may like water every 1-2 weeks. Other plants may need water at least once a week or even more often during the summer.
We say that some houseplants like to be watered every week or every month, but it’s also true that you have to adjust this type of advice for your specific houseplant. More than just the type of plant, the season, potting soil mix, drainage, temperature, and air humidity level will all influence how much and how often a plant needs water. Even if it survives as a hearty plant, very few houseplants will do their best from being watered the same year-round. Most every plant needs more water in the summer and less in the winter.
With experience, you may be able to anticipate these adjustments on your own. If you’re still learning how to care for a new houseplant, a soil moisture sensor will help you know exactly when it’s time. These meters can give you a range of readings from wet to dry. You can also take readings at different soil depths to know when to water houseplants that like more or less moisture.
How Much to Water Your Houseplants
A good general rule of thumb is that you want to use the least amount of water that will get all of the soil and every side of the pot wet. If your plant is in a pot with good drainage, you want to keep putting a small amount of water on each side of the pot until water starts to come out of the drainage holes. That said, there are several factors that influence how quickly the water runs through the pot. For one thing, potting soil mixtures can retain more or less water in the soil. If you’re watering modestly and infrequently but still see signs of root rot, you may need drier potting soil. If you’re watering generously but still signs of underwatering, you may need potting soil that retains more water.
That said, if you know the type of houseplant and match the potting soil mix, you’re unlikely to have this type of problem. Usually modifying the watering schedule and the water amount is sufficient to find the sweet spot for your houseplant to take off.
Get a squeeze bottle with a squirt nozzle that make it easy to reach into the houseplant near the potting soil. Unless it already has measurements on the bottle, use a marker to indicate at 3-4 ounce intervals how much water is in the bottle. These measurement lines are also helpful in modifying the amount of water the plant receives based on changes to the light, temperature and humidity levels, as well as the plant’s natural bloom-and-dormancy cycles.
Another tip for knowing both when and how much to water your houseplant is to weigh the plant. Dry soil weighs a lot less than wet soil. If you have good weight perception and know your houseplant, you may be able to do this by feel alone. If you’re less confident, you can also get a scale to weigh your houseplant before and after watering—and then adjust as needed to keep the plant healthy.
How to Water Your Houseplants
It’s helpful to have a bottle or watering can with some type of nozzle or long neck. This will help you control where the water goes and should allow you to get every side of the pot wet without overwatering. In general, we like to water directly into the soil. If nothing else, it keeps water from running off the plant and on to the table, desk, or shelf.
Contrary to popular belief, most houseplants are perfectly happy if their leaves get wet. There are notable exceptions, however. If the leaves capture and hold water for long periods of time, this can lead to mold and fungus. African Violets, for example, are vulnerable to this type of problem, especially when using cold water. That said, we will also occasionally mist our plants to help remove dust and keep the leaves clean. Misting is also helpful for houseplants in dry summer climates and homes without air humidifiers, but it’s not a substitute for watering the soil.
Finally, there is choosing what type of water you will use for your houseplants. We usually recommend filtered water, but you can read more about using Tap, Filtered, Distilled, or Rainwater for Houseplants.