How Often Should You Water Indoor Plants?

QUESTION: How often should I be watering my indoor plants? I can’t seem to figure out the right watering schedule for them. — Jim F.

ANSWER: There’s no simple, one-size-fits-all answer to your question, because different plants will need to be watered at different times. However, we can tell you how to determine when your plants need water so you can give them the hydration they need to grow healthy and strong.

You’ll see some advice that tells you to water indoor plants once every so many days or weeks … but we’re here to tell you that this advice doesn’t take individual plant preferences into account and is unlikely to result in a happy garden. It isn’t only up to the type of plant you are growing—the container, potting media, humidity, and temperature are all factors in how much water a plant needs. So instead of trying to choose a certain watering schedule, we’ll teach you what to look for so you’ll know when a plant is ready to be watered, and even when a plant has been getting too much water, so you can adjust your watering as needed.

Do the Finger Test

For most indoor plants that are not cacti or succulents, you can perform a simple test to see whether the plant needs to be watered. Just insert a finger into the soil where your plant is growing to a depth of two inches. (If you can’t get your finger two inches into the soil, the plant may be rootbound, or your potting mix may be too dense.) If the soil feels moist or clings to your skin, the plant doesn’t need water just yet. When the soil is dry and does not stick to your skin, it’s time to water your plant.

Check the Weight

A plant with soil that has dried out will be much lighter than one that is still moist. Try lifting up the plant, container and all, to check its weight. If you do this every so often, you’ll learn what the plant’s normal weight is when watered, and you’ll be able to feel how the plant is lighter once the soil has dried.

Instead of watering your plants each day, instead just check on them to see if they need water. While you shouldn’t water on a set schedule, you should do an inspection of your plants regularly so you can see when they need water, or when they’ve been getting a little too much. You just need to know what to look for. We’ve told you two ways to check and see whether a plant is ready to be watered, and now we’ll tell you how to read the plant’s signs that indicate overwatering or underwatering.

Know the Symptoms of Overwatering and Underwatering

Your plants will show you when they need water or have been getting too much. If you know these signs, you’ll be able to adjust your watering regimen as needed.

Overwatering

One of the signs of overwatering is drooping, wilting foliage—which is confusing, because drooping and wilting can also be a sign of underwatering. However, if you see drooping or wilting foliage while the soil is moist, your plant is getting too much water. You may also notice yellowed leaves. A plant that is getting too much water will not be putting out new growth. The presence of fungus gnats or an unpleasant smell coming from your plant also point to overwatering. If you see these signs, reduce the amount you are watering and use the finger test so you’ll know for sure when the soil is dry and it’s time to water your houseplants.

If you have scaled back on watering and are still seeing these symptoms, it’s possible that your plant has root rot. Check for root rot by carefully removing the plant from the soil, roots intact. Gently use your fingers to shake off the excess soil. Then examine the roots. If the roots are slimy or dark in places instead of the pale color of healthy roots, your plant has root rot.

If your plant has root rot, you will need to remove the diseased roots and repot the plant. Use a clean, sterilized pair of gardening shears, snip away the slimy or darkened root sections. (You can sterilize your shears by soaking them in a mix of half water and half rubbing alcohol for five minutes. Then rinse them under fresh water and let them air dry.)

Then you will need to put the plant in a new, clean container with fresh new soil. Discard the old soil, but do not put it in your compost heap. You can reuse the container once it has been cleaned and sterilized. Once you have repotted the plant, scale back your watering and use the finger test to determine when it’s time to water your plants.

Underwatering

Underwatering can look similar to overwatering, but instead of these symptoms appearing when soil is wet, they’ll appear when soil is dry. You may see drooping, yellowed, or withered leaves, or the leaves themselves may turn brown at the tips. These symptoms in conjunction with dry soil mean the plant needs more water than it is getting. Make sure to water deeply, as we explain in the next section, and monitor the plant regularly so you’ll know when more water is needed.

How to Water Houseplants

You can water houseplants either from the top or from the bottom. Either way, you should give plants a deep watering, and we’ll tell you how.

Make sure that you use room temperature water on your plants. All your plants should be in containers that have drainage holes. You may hear advice about using rocks or broken pottery in the bottom of containers if they don’t have holes, but this is not really effective. There’s really no substitute for having enough drainage, and it’s very important to keep plants healthy and prevent root rot.

Smaller plants will need to be watered more frequently than your large plants. Plants in sunny spots will need to be watered more frequently than plants that get a bit of shade.

Keep the time of year in mind when you’re watering, because plants that go dormant during the off-season don’t need nearly as much water during this time. If your plant goes dormant in fall and winter, scale the watering way back. Not familiar with this concept? Check out our article Dormant Plants: Your Top Questions and Answers.

Watering From the Top

It’s not sufficient just to sprinkle a bit of water on top of the soil where your plants are growing. Instead, you need to do a deep watering. Aim for the root area, and keep on watering the plant until moisture starts to leak out of its drainage holes. If your plant is in a saucer or tray, pour out any excess water after the plant has had 10 minutes to soak it up.

Watering From the Bottom

To water from the bottom, fill up the plant’s saucer or tray—or a basin you can set the plant in—so the plant can soak up the water through the drainage holes in its container. Keep refilling the saucer until the plant stops taking in the water. Or, if you are soaking the container in a larger dish, let the plant soak for 10 minutes. Once you are finished watering the plant, dispose of any excess water remaining in the saucer, tray, or basin.

Exceptions

There are a few plants that have special watering instructions you should be aware of.

Cacti and succulents: These plants need far less water than other houseplants. Water them only when the soil has dried out completely.

Orchids: Orchids need a little bit of water about once a week.

Citrus: These plants need to be watered much more frequently than others. Don’t let them dry out, but keep them consistently moist. However, you don’t want the plant to be waterlogged, so go for damp instead of wet.

Soluble Salt Buildup

Soluble salt buildup happens when the minerals in water slowly accumulate in your plant’s soil over time. Symptoms include brown leaf tips, dropping lower leaves, dead root tips, wilting, and reduced growth. You may be able to see the salt deposits around the drainage hole, on the outside of the container, or inside near the soil line. Avoid watering plants with soft water, which has the most soluble salts.

To prevent soluble salt buildup, either use distilled water or rainwater. You can also let soluble salts evaporate by drawing your water 24 hours before you will water the plants. After settling for a day, the chlorine in the water should have evaporated, and most harmful minerals will have settled to the bottom. Just pour out and discard the bottom inch or two of water.

Every four to six months, and as soon as you bring a new plant home, you should flush out the salts that have built up in the soil. (Even if you personally use distilled water, rainwater, or draw your water early, you should flush out the salts when you get a new plant, since you don’t know how much salts may have built up from the nursery’s care.)

Start by examining the top layer of the soil for a crust of salt. If this is present, remove it with your hands before starting the flushing process. It is best to use distilled water, rainwater, or water drawn a day early to flush with. Start by pouring clean water, at least twice the volume of the pot, over your plant. Then let the excess water drain out through the drainage holes. Do this two or three times. Do this before you fertilize the plant, since you don’t want to wash away newly applied fertilizer.

You’ve learned a lot about watering houseplants from reading this article. Now you know the symptoms of overwatering and underwatering, so you can tell when a watering regimen needs to be adjusted. You also learned how to tell when your houseplants need water by using the finger test or checking the weight of the pot. Then we discussed how to best give your plants a deep watering, from the top or from the bottom, and how to prevent soluble salt buildup. Remember, just because you’re not watering your houseplants daily doesn’t mean you should ignore them. Check on your plants every day to read their signs and test the moisture level. That way you’re sure to see when they need more moisture.