Houseplants require different care in the winter months

By Bev Johnson | The Daily Journal

Published Saturday, February 23, 2008

Jeff Hahn is our bug guy from the University (his real title is Extension Entomologist), but bug guy works for most of us. He reminds us that this is the time of the year that we start to notice problems with our house plants.

Sometimes, we brought the bug in when the outdoors vacationing plant came in for the winter. Or it may have snuck in through the screen of an open window. Worse yet, it may have hitch-hiked in on a plant from a friend or from a plant you bought.

Even a live Christmas wreath could be the culprit. At any rate, you don’t want a buggy plant. So what should you be looking for? Discolored leaves. Not all of them are infested. Poor light, too much or not enough water or just old age of the leaf can cause discoloration.

Webbing on the plant is a sign of spider mites. You will need a magnifying glass to see them. Or, you can hold a sheet of white paper under a leaf, tap the leaf and see what falls off. Yellow sticky traps will capture whiteflies, thrips, fungus gnats and winged aphids.

Unfortunately, Jeff doesn’t tell us where to buy yellow sticky traps. Improvise.

So how do you get rid of your unwelcome house guests? Here is what Jeff suggests.

Wipe off the pests with a soft rag or paper towel dipped in rubbing alcohol. Not for hairy leaves, however.

Or a solution of a dishwashing detergent, 1/2 teaspoon to a quart of water. Be very careful with that as it can also damage some plants.

If these don’t work or you have a heavy infestation, you can try insecticides. There are two manufactured by Bayer. Bayer advanced 3 in 1 Insect, Disease & Mite Control. Each has a different chemical combo.

They are generally effective against whiteflies, mealybugs, aphids and scale. Check the labels for your bug.

Bonide sells for bug killers: Bonide Houseplant Helper, Bonide Systemic Houseplant Insect Control, Bonide Insecticidal Soap, Bonide Bon-Neem and Bonide All Seasons Bug Beater Horticultural Spray Oil. All list their target bugs. If you have fungus gnats only, Gardens Alive Knock Out Gnats, is listed.

This is only available from the Gardens Alive catalog. There is a copy at the Extension office.

Here is a home remedy for fungus gnats. For a small plant, dump out the soil, wash the roots clean and pull off any rotted roots. Scrub the pot with 1/2 teaspoon bleach to 1 quart of water. Repot in soilless mix. For a big pot, cover the soil well with 1 to 2 inches of pebbles. Colored aquarium rocks could even match your color scheme.

Moral for this week: don’t overwater, watch for bugs and get them while they’re small.

Bev Johnson is a master gardener for West Otter Tail County.