Watering2 min read

Bottom watering: how and when

Let the pot drink from below and keep the leaves dry

What bottom watering is

Instead of pouring water on top, you stand the pot in water. The mix draws it up through the drainage holes, the way a paper towel soaks up a spill.

The leaves and the crown stay dry, and the whole root ball gets wet evenly.

When it helps

Bottom watering is handy for these plants and situations.

African violets and other fuzzy-leaved plants. Water on their leaves leaves pale marks, and wet crowns rot.
Seed trays, where pouring can wash seeds and fine mix around.
Potting mix so dry that it sheds water instead of soaking it up.
Begonias, cyclamens and other plants that dislike wet leaves, and plants too bushy to water underneath.

How to do it

It takes a little hands-off time.

Use a pot with drainage holes.
Set it in a tray, bowl or sink with about 2 inches (5 cm) of room-temperature water.
Leave it until the surface of the mix feels moist, often 15 to 30 minutes, and never more than an hour.
Lift it out and let the extra water drain away. A wilted plant that has perked up has had enough.
Don't leave it standing in water. Roots need air as much as water.

Seed trays

Stand trays of seedlings in a shallow tray of water just until the surface of the mix darkens, then lift them out to drain. That often takes only a few minutes.

Watering from below also keeps tiny seeds from washing away or sinking too deep, and the wet mix stays moist longer than you'd think.

The one catch

Bottom watering doesn't wash anything through the pot. Minerals from hard water and salts from fertilizer stay in the mix and can build up, sometimes as a white crust.

Every few months, water from the top instead, slowly, until plenty runs out of the bottom. Feeding at the rate on the label, and not more, helps too.

Sources

General guidance, not a diagnosis. Written by PlantWiz in our own words from the sources above.