How to Avoid Overwatering Your Houseplants, According to Master Gardeners

Watering regularly is one of the golden rules of plant ownership. On the surface, that task seems simple enough, but as many plant owners know, it’s not always as easy as it sounds. In an effort to keep a plant hydrated, even the most savvy individuals can mistakenly overwater it. So what are the signs that your plant is overwatered, and how can you avoid doing it in the first place? We spoke to several experts and got their tips and tricks for keeping your plant happy, hydrated, and thriving.

Understand Your Plant's Needs

The number one thing you can do to avoid overwatering your plant is to understand its individual watering needs. Matt Mattus, senior horticulturist and director of special projects at the American Horticultural Society, recommends plant owners do a little research first to identify the type of plant they have, as well as its watering preferences.

Joe Moussa, owner of Mosaic Home & Garden Center, agrees: “The real key is understanding your actual plant.”  Moussa, for instance, has a schedule that requires him to be away from home, so he's partial to succulents that can happily tolerate longer dry spells. Tropical plants, which many of us have at home, are far less forgiving during our absence.

Know the Right Way to Water

It’s tempting to grab a watering can or pitcher to give your plants a thirst-quenching stream of water, but that’s not necessarily the best way to do it. “The best way [to water] is to take your plant to the sink and soak it really well, or soak it in a bowl of warm water and let it drain out completely," says Mattus. "Then set it back on the tray.”

Check Soil Moisture

Even the best-kept schedule can be detrimental if you’re not paying attention to soil moisture.  Susan Detrick, a seasoned master gardener and the coordinator of Monroe and Pike Counties at Penn State Extension, offered some helpful tips to ensure you’re only watering your plants when it’s most needed:

• Insert your finger, a popsicle stick, or a ruler about 2 inches into the planter. If the instrument has soil on it, you likely don’t need to water it. 
• Know the weight of your potted plant. Dry soil will be lighter. If it’s heavy upon lifting, you may not need to water it yet. This, of course, means you should know how the planter feels when it's dry and when it's recently watered. 
• Use a moisture meter, a device that measures the moisture in your soil. These are readily available at most garden centers and stores that sell gardening products.

Keep in mind that even these methods first require that you understand your plant’s unique soil moisture needs.

Note Seasonal Changes

Watering needs will change with the season. “In the summer, when a plant is in active growth, it could obviously take up more water," says Mattus. "However, in the winter, a lot of plants slow down, so they're not using as much water.”

That said, Mattus adds that plant owners should still be diligent in the winter months, especially when the heat comes on and the air gets dry. Setting a schedule, even just to check the moisture level of the dirt, can be extremely helpful. 

Choose the Right Planter or Pot Size

One size does not fit all when it comes to plants, especially in terms of watering best practices. “It's not just the container itself, but it's also the size in relation to the actual plant,” says Moussa. 

When the planter is too large for the plant, that means that the ratio of the soil to the root system is considerably higher, "So your root system will not have enough time to absorb the moisture in the entirety of that container," says Moussa. "The system will end up sitting in moisture-rich soil, without the ability to deplete that moisture." Eventually, this can lead to root rot. 

To avoid this, Moussa recommends against buying a pot that your plant will “grow into" and instead gradually moving your plant into a larger container as it grows.

Promote Proper Drainage

“Roots require oxygen,” says Mattus—something that many plant owners may not realize. When plants are overwatered, the roots become saturated and can’t get that much-needed oxygen. Proper drainage can help avoid that, and a great way to ensure your plants get enough oxygen is to use a pot with drainage holes.

Choose the Right Soil

Mattus and Moussa were both quick to point out the role that soil plays in watering, noting that soil requirements can vary plant by plant. "If you have something like a cactus or succulent, for example, it may require soil that has a lot more drainage," says Moussa. 

Other plants prefer something more specific. “Orchids like a specialty blend, [which] we just call orchid bark, that their roots prefer to be in," says Mattus. "Their roots don't like being trapped in soil or compacted in soil.”

If you’re not sure, Moussa recommends reading the potting soil bag before purchasing, or checking with your local gardening center to find the right blend for your plant.

Also, don't assume that soil concerns end after the initial potting. Mattus warns that potting soil isn’t the same as outdoor soil, and it's important to take that into consideration. “After a year, it gets compressed and doesn’t hold oxygen," he says. Repotting your plant with new, nutrient rich, less dense soil can help it thrive.

Know the Signs of Overwatering

The experts all agree: If you see your plant's leaves yellowing, then overwatering may be the culprit. Mattus notes that it’s even more likely if the yellowing is occurring towards the top of the plant. 

Other potential signs of excessive moisture include gnats gathering around the base of the plants, as well as an off odor that can signal rot, according to Moussa.

If you think your plant is the victim of overwatering, the first thing to do is to stop watering it. Once yellow leaves start to set in, you’ll likely need to take further action, as overwatering can lead to root rot. In most cases, you’ll need to remove the plant, cut away the affected roots, and then repot it using new soil.