Meg's Guide to Gardening: DIY Houseplant Spray

I let my houseplants enjoy some sun on the porch for a few days and they repaid me with an outbreak of spider mites. Lucky for me, the internet came to the rescue again. Thanks to the experts at Colorado State University Extension, I now know how to make my own houseplant insecticide. It's easy to make: all you need is a little soap. And, it kills all manner of houseplant insects including aphids and mealybugs.

How to Make It
Fill a spray bottle with one quart of warm water. If you have hard water, use bottled water for the mixture. Next add roughly four teaspoons of liquid detergent soap. The dish soap you have next to your kitchen sink will do just fine. Congratulations. You've just made your own insecticidal soap. Stir the mixture with a chopstick or the tube that extends from your spray bottle's head. Don't shake it. You'll just make bubbles.

Test it Out
Some plants are sensitive to insecticidal soap. Here's how you tell if your plant is one of those: spray a few leaves with the houseplant spray late in the afternoon. Wipe it off in three hours. Come back and check the plant in 48 hours. If the leaves are still green (or whatever color they were before) and healthy, you're safe to proceed. If they turn brown or otherwise look sickly, you'll have to find a new method of getting rid of your houseplant's creepy crawlies.

Spray the Insects
The best time to spray your houseplants is early in the morning or late in the afternoon when the sun is on its way in or out. Spray the entire plant until it starts dripping. Focus on the spots where you can see the insects. Look in the nooks between stems and under leaves to find any bugs that are trying to hide. This houseplant spray works on contact so you have to be sure to soak the little blighters. After you're done, wait three hours and then wash the plant off with water from your watering can.

Spray Again
Re-spray the plant every four days until the insects are gone. If you don't notice a decrease in the insect population after two or three sprays, increase the dosage to two tablespoons per quart of water. Test the new houseplant spray, and then treat the entire plant at four day intervals until the insects die.