Skip to content

Houseplants 101

The first rule of houseplant care is that houseplants should enhance your home. Take a critical look at your houseplants.
garden chat
A well-tended, easy-to-care-for African violet. Photo by Malcolm Koo

The first rule of houseplant care is that houseplants should enhance your home. Take a critical look at your houseplants. Do they have yellowing leaves, long stems with no leaves, stakes because the weak stems are unable to hold themselves up or has a flowering plant (e.g. poinsettia) not flowered in years? If “yes” to any of these questions, then consider starting fresh.

Plants, like all living things, need six things to thrive — light, hospitable temperatures, shelter, water, food and freedom from duress (pests and disease). Of course no two types of plants need exactly the same growing conditions, but there are broad acceptable ranges of these six factors that allow you to lump plants with similar needs together.

Most houseplants that do well in our homes are from the tropics, usually understory or shade-loving plants. During the summer, place your houseplants away from direct sun. From October to March, most houseplants welcome the weaker winter sun, but remember to move them back away from direct summer sun.

Being of tropical origin means houseplants are not adapted to temperatures much lower than 55 F for any length of time and no time at all below 40 F. Keep them away from drafty doors and windows in winter. Also, do not trap plants behind curtains.

Besides the protective environment of your home, shelter includes the root zone contained within the pot. Plant roots need a suitable potting media. When restricted to a small volume, that potting media needs to be light, porous, well draining but with some water-holding capacity. Most commercial potting media is soilless, usually some combination of peat, perlite and vermiculite. Rarely is there any soil included as soil is too heavy and may contain pests and disease.

Tap water is usually suitable but do not use softened water as this contains toxic (to plants) salt levels. Apply as required, when the top half to one inch of the media feels dry to the touch. Never allow your pots to sit in water, as this will cause the potting media to remain soggy leading to root death.

While plants manufacture their own energy compounds from light and air, they do need nitrogen, phosphorous and potassium in relatively large amounts. Required in much smaller amounts, but still essential, are chemicals such as copper, magnesium, iron, manganese and the like, known collectively as micronutrient. Since plants cannot go out in search of food, it means that you’ll have to supply them. Use a complete, dissolvable granular fertilizer (20-20-20 plus micronutrients) and apply according to package instructions one to four times a month, depending on the plant and time of year. Or use a controlled-release fertilizer in pellet form applied a few times per year, according to package instructions.

Just as houseplants are perfectly adapted to your home, so are a number of insect pests. Inspect regularly for signs of infestation. Common insects that you may encounter include aphids (bright green or black, one to two millimeters long, soft bodies, usually found on the most succulent and youngest growth.

Spider mites are microscopic and are usually on the undersides of leaves. Symptoms include yellowing leaves and fine webbing, towards the ends of branches.

Mealybugs are small, oblong, cottony-white puffs, three to five millimeters, on young growth or in the root system.

Scales are raised, round brown bumps on stems and leaves of recent growth.

Fungus gnats are small flies, one to two millimeters, hovering at the soil level.

White flies are two to four millimeters, are powdery white and are usually on the undersides of young leaves.

We end where we started. Houseplants should enhance your home. Groom your plants to keep them looking their best and inspect regularly for problems. Remove dying, yellowing leaves and spent flowers. Plants that can become leggy, like coleus, should be trimmed back regularly. Invest in a houseplant guide that describes your plants, ideal growing conditions and pests that are likely to attack.

— This column is provided courtesy of the Saskatchewan Perennial Society (www.saskperennial.ca; hortscene@yahoo.com; www.facebook.com/saskperennial). Check out our Bulletin Board or Calendar for upcoming garden information sessions, workshops, tours and other events: Oct. 26, 7:30 p.m. - Cultivating Nature's Palette - with native prairie perennials; Emmanuel Anglican Church (free).