Bottom watering houseplants is popular among some people, but if you don’t know why and how to water plants from the bottom, you could end up hurting the plant. The harm can happen primarily in one of two ways. Either the water doesn’t reach the top of the soil leaving it perpetually dried out, or the water sits in the bottom of the pot for too long causing root rot infiltrate the root extremities and spread up from there. At the same time, there can be solid reasons for choosing this strategy, at least some of time, for watering houseplants.
Why People Choose to Bottom Water Houseplants
- Cold Water Spots: Some houseplants are susceptible to permanent cell damage from the thermal shock of cold water landing on their leaves. The tiny white scars that form are mostly harmless. One solution to avoid cold water spots is to water that is close to room temperature, but bottom watering also helps guard against this problem. Similarly, the minerals in hard tap water can leave a powdery mildew. Use filtered or purified water. If you bottom water with tap water, it’s a good idea to periodically measure the soil pH and amend the potting mix as needed for that houseplant.
- Wet Feet and Rotting Crowns: Have you heard there are some houseplants that don’t like wet leaves? First, it’s important to know that these plants are, in fact, fine with their leaves getting wet. It’s the divots at the bottom of the leaves, known as the crown, that can suffer from rot when water collects in these areas for too long. If you notice a lot of water has fallen into these crowns during top watering, it’s not a bad idea to take a paper towel and soak some of it up. But another way to get around this problem is to bottom water these plants most of the time.
- Convenience and Access: Even a houseplant with foliage that doesn’t mind getting wet can be difficult to water from the top, if the foliage and stems are crowding out access to the potting soil. Watering from the top may lead to runoff and make a small mess. Access may also be an issue with a tall wall shelf, where you can barely reach the plant to begin with. Why not just put the houseplant in a catchment pot and put a bunch of water in there for the roots to soak up? This is certainly an option, but to do it right, it may not be as convenient as you think. It’s simply too hard to get the water levels right where the plant can soak up enough water without exposing the bottoms of the root to rot.
- Fungus Gnats and Moisture-Loving Pests: For some environments and for some plants, it may be beneficial to keep the top level of potting soil. To be clear, most houseplants pests thrive in lower humidity levels, but there are a few exceptions, and fungus gnats are by far the most common of these. Thus, if you live in a more humid climate and you’ve had trouble with fungus gnats in the past, you could try to moving to a mostly bottom watering technique as part of your gnat control and prevention measures.
Tips for Bottom Watering Houseplants
- Rather than throw a bunch of water in a catchment pot indefinitely, use a removable catchment. You can then soak the houseplant in water for about 10-20 minutes, depending on the type and size of the plant, before removing the catchment and letting the roots breathe.
- Get a fancy self-watering pot. We recommend the kind with separate reservoirs, overflow holes, and a wick to draw the water up to the top of the plant. Basic self-watering pots may also work, but you continue to run the risk of root rot.
- When generally watering houseplants from the bottom, you might get out a water bottle and mist the top of your plants and soil. This will keep the top of the soil from drying out completely with minimal risk of rot.