In the Garden:
Southwestern Deserts
June, 2005
Regional Report

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Watering meters can take the guesswork out of deciding when it's time to water.

Summer Houseplant Care


Many houseplants are dormant during winter months and start pushing out new growth as days lengthen. They need more frequent watering to keep pace with growth, especially if they're in a sunny spot where the soil dries out faster. I have a table of plants in a western exposure and they dry out much faster than others, even though I close the blinds during the afternoon to give them a respite. If southern or western windows become too hot, consider moving plants to an eastern exposure. Even my northern exposure in summer provides sufficient light for many houseplants.

When to Water
Stick your finger into the soil to determine how much moisture there is. However, this can be difficult if the plant is covering all of the surface area and there's no room to fit a digit. Deep containers also create issues. I have a tall columnar cacti in a 15-inch-deep pot. Poking around in the soil is problematic because of the depth and the spines, so I use a soil moisture meter. There are many styles, with some type of a pointy probe to insert into the soil.

Another testing method is to simply lift the pot. When the soil is dried out, the pot will be much lighter than when the soil is saturated. Foliage also will provide tell-tale signs, such as wilting or a general lack of luster. Instead of being a vibrant and healthy green, the foliage looks washed out. Succulents look wrinkled. It's not a good idea to wait for those signs to appear before watering, as it's stressful for the plant. Stressed plants are more likely to succumb to pests or disease.

Make sure the entire root ball gets moistened. When container plants dry out, the soil pulls away from the sides of the pot, and water tends to pour down the sides and out the drainage holes before it can saturate the soil. To combat this, I put houseplants in the kitchen sink with a very slow drip from the faucet. They also can drain without me having to empty saucers later or mop up around saucers that overflow. At the same time, the plants enjoy a spritz of water on their foliage with the dish sprayer to increase humidity and wash off dust. (Not that there's any dust in my house...)

Fertilize or Repot?
If the plant has filled out the entire pot, roots are poking through the drainage holes, or it's been in the same soil for two years or more and doesn't seem to be putting forth much new growth, it's time to repot. Use a good quality potting soil that contains pumice or perlite, both of which improve drainage. I like pumice better because it absorbs water and releases it back into the soil. Perlite often washes away through the drainage hole. Combat that during repotting by cutting a square of window mesh screen to cover the drainage hole. Water can still drain out, but soil doesn't. If repotting isn't necessary, fertilize with an all-purpose houseplant fertilizer according to package instructions.


Special Report - Garden to Table