Gardening

10 Neat Things about Watering Houseplants

Woman watering houseplants with white plastic watering can.

Here’s a great little article by the friendly people at Canada’s Local Gardener, a new garden magazine you’ll certainly want to look into!

1. When to water.

Finger inserted into pot of fern to tell if it needs watering.

Use your powers of observation when watering houseplants. If the top one-inch (2.5 cm) of the soil is dry and the plant looks thirsty, add water. In general, water less when the light levels are low and more when the plant is actively growing. (If your house is very dry in winter, you may have to water more often than at other times of the year, so use some judgement).

2. How much is too much?

Plant with yellow leaves caused by overwatering.

If the soil is wet or soggy , your plant is being drowned. Plant roots, especially the top one-third, need oxygen, which exists in soil between the soil particles. When you over water, you suffocate the plant by forcing the oxygen out of the soil.

Wilted fittonia with white nerves on green leaves.

3. How little is too little?

There is no set rule in watering houseplants. Some cactus can retain water in their stem for up to two years! Other plants need to be kept uniformly damp in the water root zone. Your plant will tell you it’s thirsty by wilting and, if you leave it long enough, by dying. If the soil is wet or soggy, you’re watering too much. If it’s just damp, don’t add water yet. If it’s dry on the surface and for an inch (2.5 cm) below, it’s time to water. Get to know your plant and use those powers of observation.

Plants in shower to be hosed down.

4. Give your plants a bath.

Take the whole pot to the sink. Give the leaves a shower and let the water run right through the pot. This washes out harmful salts that build up from unused fertilizers. Remember, heavy showers emulate what happens in nature: It rains. It pours. The water saturates the ground, but quickly sinks away to the water table leaving the top few inches of soil pleasantly and refreshingly damp. Use room temperature water.

Potted plant sitting in a tray of water.

5. Drain and drip dry.

Drainage is the key. When watering houseplants, there should never be standing water in plant saucers. Think of what would happen if your own feet were left in water for days at a time! For plants, roots can rot, and that can mean death.

Dead plant in pot with rotted roots.

6. Over/under watering symptoms.

Leaf or bud drop can indicate both under or over watering. It’s normal for plants to shed old leaves, usually those at the bottom of the plant, but yellowing or browning of other leaves can also be another symptom of improper watering. Mould or fungus growing on the soil, stems, or leaves clearly points to over watering.

Ficus lyrata with brown markings near leaf tip.

7. Brown spots on leaf tips.

Improper watering of your houseplants can cause the browning of leaf tips, which can also be caused by the chlorine in our tap water. Some plants are more sensitive to chlorine than others. You can sometimes overcome this by simply leaving tap water out overnight to allow the chemical to dissipate, but more and more municipalities now use chloramine instead of chlorine to treat water and it doesn’t evaporate. You might need to water such plants with rainwater to avoid damage.

Yellow sticky trap with fungus gnats.

8. Fungus gnats.

Those pesky little flies that sometimes surround houseplants in winter are another symptom of too much water. Fungus gnats lay their eggs in damp soil in the top one-half to one (1.5 to 2.5 cm) of soil. They love organics-rich soil and plenty of moisture. Let the top inch (2.5 cm) of soil of your houseplants dry out to discourage these beasts. (You can also drench the soil with neem oil or a commercial pesticide powder available at most garden stores. Capture the flying adults with a strategically placed saucer of vinegar).

Photo: amazon.ca

9. Plants that grow in water.

So if plant roots need oxygen, how come hydroponics work? The answer is oxygenated water. Stagnant water will kill the plants, so oxygen is introduced via air pumps and air stones, which break up oxygen bubbles into smaller particles. Some plants are designed to grow in water and have little air bladders on their roots.

Bottle of distilled water.
Photo: London Drugs

10. Distilled water is dead water.

Feeding plants with distilled water is counter-intuitive! Plants use minerals dissolved in water. Distilled water removes minerals (and also changes the pH of water). Drinking distilled water can be harmful to your body. Don’t feed it to your plants except those, such as carnivorous plants, that are intolerant of hard water.

– Dorothy Dobbie
Copyright © Pegasus Publications Inc.

Unless otherwise mentioned, all photos generously offered by Canada’s Local Gardener.

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

1 comment on “10 Neat Things about Watering Houseplants

  1. Okay, I do like some houseplants. There were a few plants that I brought back from Southern California that did not want to be outside here. Besides, my former home in town was very sunny, but lacked space for vegetation outside some of the windows.
    However, houseplants had to adapt to my lifestyle. Hydroponics and artificial lighting and all that some people put into growing houseplants is just too much. Greenery in the home might be appealing, but too much infrastructure for the sake of such greenery is . . . excessive. I could not deal with all that plastic and electricity and . . . whatever it all is.

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