Updated: Sep 6
Pests are a gardener’s biggest worry, and for good reason - an infestation can wreak significant damage if not checked.
Unlike plants grown in-ground, container plants are mostly pest-free, making them ideal for low-maintenance gardening. Container plants also get more scrutiny as they’re usually closer to eye level, so gardeners have the advantage of being able to head off infestations on time.
But that doesn’t mean that container plants don’t get pests. An infestation can be unpredictable and cause problems without warning.
The most common container plant pests include spider mites, aphids, whiteflies, fungus gnats, and thrips. They all have their different identifiers, but that’s not the purpose of this article.
Before you get pests, you can take some key steps to increase your plant’s chances of staying healthy. Here are a few tips to control container gardening pests:
1. Buy healthy plants from accredited nurseries
Many problems can be avoided by selecting the healthiest plants because, the healthier the plants, the more they can withstand minor pest invasions.
Every gardener should expect some insects and minor pests, but healthy plants are able to withstand them or bounce back quickly. That’s why we always say-buy seeds and plants from good nurseries!
Nurseries are usually run by gardeners with experience who take great care to keep their plants in good condition. That’s your best bet.
2. Quarantine and treat new plants
This is not a hard and fast rule, but you can never be too careful with plants coming in from environments you cannot vouch for.
To be extra cautious, you can separate the new plants for a few days/weeks and use that opportunity to ‘treat’ them before you add them to your existing plant collection.
Here are some steps to take with a new plant:
● Remove old gardening soil and wash the plant’s roots.
● Wash the leaves with water and horticultural soap and wipe them dry
● Let the leaves air dry, then look under them for any ticks/spots/insect larvae. Remove any you find. For extra security you can wipe the leaves down with rubbing alcohol.
● Repot the plant with an appropriate soil mix
● Fertilize and water the plant.
● Watch the plant closely over the next few weeks for any changes.
3. Plant using clean materials
Clean containers help to avoid infestations. Don’t neglect to regularly clean your gardening materials – and especially containers, before using them for new plants.
● Scrub plant containers and tools with soap and water, and disinfect with methylated spirit especially if the plant that was in it had root rot.
● Soak containers that might have been previously infested with pests or diseases in a solution of bleach and water for about a couple of hours, rinse thoroughly, and air dry before using them again.
● Do NOT reuse potting soil. Old potting soil may be contaminated and may contain newly hatched slugs/snails, insect eggs, and unseen larvae. You can add used potting soil to your compost bin.
4. Natural pest control
Natural pest control uses flora and fauna in the environment and natural pesticides to control pests. Introducing beneficial insects like ladybugs and ground beetles are a natural way to control plant-eating bugs in your container garden. Just make sure the insects you’re introducing will not upset your garden’s natural ecosystem.
Organic pesticides like neem oil are also great for your garden.
5. Grow pest-resistant varieties
Select plant varieties that are known to have some resistance to common pests. A little research for suitable varieties to reduce the problem will be helpful. For example, select potatoes that are resistant to eelworm attacks.
Another way to do this is using companion planting to protect plants that are susceptible to pests. For more on this, here’s our Guide on Companion Planting.
6. Throw away infected/dead plants
We know it may be hard to let go of that plant baby that just won’t stop fighting off pests, but sometimes, that’s the best thing to do.
If you find a plant or plant cluster that has been infested, isolate it and try damage control. If the plant(s) is damaged beyond saving, get rid of it. Ultimately, only you can say when you want to give up on a plant that you can’t just save.
Observation is every gardener’s best friend. Once you see something that does not look right with your plant, quarantine the plant until you can investigate further and if possible, treat the plant.
When all else fails, it’s time to repurpose that plant for the compost bin.