Water is essential for plant growth, but many people either over- or under-water their pot plants and plants in the garden. While the rain provides free water that falls from above, we usually need to supplement this. And when we grow potted plants indoors or on covered patio areas, they rely on us to provide the life-giving water they need to grow.
It doesn’t occur to everyone, but there are different ways that you can water plants. Two obvious differences in watering are from the bottom or from the top. While there are theories that some plants don’t like being watered from above, this is what happens when it rains. Nevertheless, there are plants that benefit from bottom watering and if you’ve got a choice, a bit of both is usually best.
Is bottom watering good for plants?
Bottom watering can be a great way of watering plants. However, there are different ways of watering plants from the bottom when you grow them in containers.
One of the primary arguments in favor of bottom-watering plants is that some species don’t like water on their leaves. Many people cite African violets as an example, even though they generally thrive in warm, humid environments and do well if you mist their leaves regularly.
The other is that by directing the water at the base of your plants ensures that the roots are properly hydrated.
At the same time, there is a good argument for sometimes watering from the top, especially if your potted plants aren’t out in the open where they will be irrigated by the rain. After all, rain is also cleansing.
So, when your plants are clearly dusty, a good sprinkling with a hose is a good idea.
Pros and cons of watering plants from the bottom
Many of the pros of watering plants from the bottom are the cons of watering from above. Similarly, many of the cons are pros of watering from above!
Pros of bottom watering
If water sits on top of the leaves of some succulent plants for too long, the sun can scorch them. The result is what looks like scarring on the leaf, but the rest of the plant isn’t usually affected unless you’ve been overwatering it. Bottom-watering plants avoid this problem.
Bottom water will soak into the soil and encourage root development. If you water from above and the water doesn’t soak in properly, roots may be adversely affected.
Another great pro, which many people don’t even think about, is that overhead watering encourages disease-causing fungi to germinate. Brian Hudelson, a University of Wisconsin-Madison plant disease specialist, explains that watering from the top creates a “leaf wetness period” that allows fungi to form.
Marisa Y. Thompson, a horticulture specialist from the New Mexico State University, reckons that the best advantage of bottom watering is to wet soil that is very dry. If it dries radically, the water may not be absorbed from above and will just run off the surface.
Cons of bottom watering
When you water plants from above, you clean them. When you water from the bottom, they will remain dusty and dirty unless you wipe them clean.
A caveat mentioned by Marisa Thompson is that placing a dish or saucer under plants can lead to the water being reabsorbed into the pot. If salts containing calcium are present in the water they can accumulate in the soil, which is not a good idea.
To overcome this issue, she suggests removing the pot and draining excess water. If salts negatively affect potted plants, the best solution is to re-pot them.
How to water plants from the bottom
The process to follow differs a little depending on whether you are watering potted plants or garden plants.
Bottom watering plants growing in the ground
When you water plant species that are growing in your garden, there’s only one way to water from the bottom. Whether you are using a watering can or a hose pipe, aim the spout or nozzle at the soil.
It’s easier to control the pressure of water when using a watering can. But it’s a tedious process refilling the can to water more than a small flower bed or veggie patch.
When using a hose pipe, don’t use a wide spray otherwise you’ll end up wetting the leaves more than you want to.
Another solution is to install a drip irrigation system. These minimize water contact with the leaves, stems, and plant fruits.
Watering potted plants from the bottom
When watering small or even larger plants that are growing in containers indoors or outdoors you can simply use a jug. Just pour directly onto the soil the plant is growing in.
All containers need drainage holes. One exception is if you grow certain smaller succulent plants. Another is if you provide a substantial layer of rocks or something similar at the bottom of the container.
Either way, you will need to minimize watering. If you’ve chosen a small glass jug or vase of sorts as a container, you will literally need just a few drops once a week.
When there are drainage holes in containers, unless you position them in the garden or on a patio where it doesn’t matter if the water drains out, you will need some sort of saucer or drain tray to catch the water. Here’s where you have an option.
You can either water the bottom, by water directly into the pot. Or you can fill the saucer with water and let the soil above it absorb water.
The problem is that there may not be enough water to irrigate thoroughly. By the same token, you don’t want the water to be totally saturated. This will also invite root rot to set in.
Can you overwater plants by watering from the bottom?
It doesn’t matter how you water your plants, there is always a danger that you may over-water them. And, the truth is that you’ll do much more harm to plants by overwatering than simply watering them from above.
You can kill plants by overwatering from the bottom. The most common result is root rot.
Ultimately, bottom watering can be more time-consuming than conventional overhead watering, but it has many pros and is probably worth the effort.