GARDENER'S READING ROOM
Indoor Plants

How Often Should I Water my Houseplant?

That’s the $64,000 question! The answer? When it needs it, of course! Now, before you throw that lovely philodendron at me, let me explain…

The key to proper watering is to maintain the correct balance of water and air-filled pore space in the potting medium. You do this by watering thoroughly (with room-temperature or warm water), then allowing the plant to dry down “to the right degree” before watering again. The right degree varies from plant to plant. People get in trouble when they try to water all their plants on the same schedule. They also get in trouble at the change of seasons. In the summer, many plants are constantly thirsty. In the fall, their needs diminish; in winter, plants need even less water. As temperatures and light levels increase in the spring, so do plants’ need for water.

Know your plant, yourself, your
environment, and that it changes seasonally!

After watering, wait to water again according to the following guidelines. If a plant needs to be watered when…

Dry: Allow the potting medium to FULLY dry (not just the surface!). Wait a few days beyond this, and then water. Be aware: some plants (mostly cacti and succulents) do not want to be watered AT ALL—or barely—during their dormant season.

Moderately Dry: Let the soil dry out about 1/2 of the way down; the bottom 1/2 should be slightly moist when you water again.

Moderately Moist: Let the soil dry out about 1/3 to 1/2 way down; the bottom 1/2 should be slightly moist when you water again.

Moist: Water when the surface is dry. These plants do not tolerate dryness and need to be fussed over.

How do you tell how far down the soil in a pot has dried? Pots normally dry out from the top down and from the edges in, so for a large pot measure (with a probe or wooden stick) about 1/2 way between the edge and the center of the pot - preferably in several spots. Note: Do not insert a probe or anything else too close to the center - you will injure the roots. Use your eyes, your fingers, your instincts, and some science.

Finally, a plant at its correct moisture level is upright and oriented toward the light; when it’s time to water, the foliage starts drooping, curling, and turning dull. Get to know your plant and what it needs and likes. And when your friends ask when you water your plants, you too will answer with full confidence, “When they need it!”

By Mary Ann Greco
Skylights Spring 2005, Vol 19, No. 1

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