A Guide to Prevent and Control Common Indoor Garden Pests

Pests are a natural part to every garden. You may think you’re safe if you are growing indoors, but they can still get in and threaten your plants. Even experienced growers will encounter them at some point or another. The best way to take care of pests, is to take preventative measures before they invade your garden, but we will also give you tips on eliminating pests should they still occur.

A general tip for preventative measures is to start from seedlings, or germinate the seeds yourself. When you purchase mature plants from a garden center, you are taking a risk that there may already be pests in the soil or on the plant itself.

Another way to prevent a pest threat is to only use clean and sanitized pots and hydroponic system components, to eliminate the possibility of a breeding ground. Also, be sure you maintain proper air flow while growing.

Note: If only some of your plants are infested, isolate them from the healthy ones to prevent spreading.

White Flies
These tiny white insects excrete a fluid when feeding, which sits on the plant and breeds sooty mold. If you have a large growing room or green house, you can release parasitoid wasps, which control agricultural pests. In smaller grow areas, you can lay sticky traps near the plants to catch the flying adults. Neem oil can be sprayed on the plant, especially the underside of leaves and stems, to stop the growth of nymphs.

Spider Mites
Only about the size of a pinhead, spider mites come in red, pale green, or yellow color. Unlike normal spiders, these mites are a threat to your garden, and will suck the juices from your plants. First signs of an infestation will include yellow spots on the tops of leaves and webs on the stems. To keep them at bay, keep your humidity level at 50%; spider mites thrive in dry conditions. For current infestations, use a pyrethrin spray, making sure to get the underside of leaves and stems.

Thrips
Very common in indoor gardens, these pests don’t usually come alone. They are yellow, brown, or black in color, and will leave behind bronze or silver colored defects on the leaves. Thrips can be shaken off, just put a piece of paper or sticky trap underneath the plant to catch them. Check the underside of leaves for brown or white spots, which are the eggs, and scrape them off and crush them. You can also spray insecticidal soap or neem oil to kill them. Another tip is to add nematodes to the soil, which will eat any pupae that fall in. You may need to treat your plants 3-4 times at 10 day intervals to completely get rid of them.

​Aphids
Aphids are tiny pear-shaped insects that are green, yellow, black, gray, or pink in color. They excrete a sticky honeydew which attracts ants, and will spread viral diseases from one plant to another. Aphids are common in outdoor plants that have been overfed, and are overly rich in nitrogen, but can gain access indoors by latching onto clothing, pets, and gardening supplies that you bring inside. To eliminate aphids, pick them off by hand or a piece of tape, spray them off with water, or apply a neem oil spray or insecticidal soap.

Fungus Gnats
Fungus gnats look like little mosquitos, and appear gray or black in color. The biggest threat that fungal gnats produce is their larvae. The flying adults do not feed on the plants, but the pale, translucent maggots will devour and destroy plant roots. They also like to feed on the algae in hydroponic systems, so be sure to use a moss and algae killing treatment to clear your system. You can also set yellow sticky traps to trap the adults. For the larvae, do not overwater your soil, remembering to only water when the top inch of the soil is dry. Add nematodes to the soil to destroy the larvae. For hydroponic systems use products such as Mosquito Bits or Microbe-Lift® BMC to eliminate the larvae.