Soil Pests in Your Plant Pots? Here’s Where to Start

What’s Hiding Beneath the Soil and Affecting Your Plants?

Small flies rising from the compost every time you water? Plants looking tired, even though you’re giving them plenty of care?

It can be tempting to change the feed or move the pot. But sometimes, the first place to look is below the surface.

Whether you grow houseplants, greenhouse vegetables or ornamental plants, understanding what’s happening around the roots can help you choose your next step.

What are Sciarid Flies?

Sciarid Flies, also known as Fungus Gnats, are the tiny dark flies often seen around plant pots. Their larvae live in the growing medium, where they mainly feed on decaying material and fungi.

The adults are usually more of a nuisance than a threat. Some larvae can damage delicate seedling roots and soft cuttings, although established plants are unlikely to suffer.

Damp compost provides favourable conditions for them. If you keep seeing flies after removing the adults, it’s worth looking at the growing medium and your watering routine.

Soil Aphids: the pests you might not see

Root Aphids, sometimes called Soil Aphids, feed on plant roots. Their position makes them harder to spot than aphids clustered on stems or leaves.

Affected plants may wilt, lose vigour or develop discoloured foliage. These signs can resemble a feeding or watering problem, so they don’t confirm an infestation by themselves.

When repotting, check for insects around the roots. Some root aphids leave white, waxy deposits, although root mealybugs can look similar. Identifying the pest helps you avoid treating the wrong problem.

Start with a closer look

Before reaching for a treatment, spend a few minutes checking the plant and its surroundings.

Look at where the insects appear. Are they flying above the compost, moving around the pot, or gathering on the leaves? Take a clear photo if you can.

Check the growing conditions too. A pot sitting in water, blocked drainage holes or a watering routine that no longer suits the plant can all deserve attention.

Finding an insect in compost doesn’t automatically mean your plant needs treatment. Focus on identifying it and checking whether it is causing a problem.

Where A.R.T.S Bio Granules fit in

For growers dealing with pests in the growing medium, A.R.T.S Bio Granules are one option worth considering.

Made from pressed neem seeds, Bio Granules can be used in potting media and hydroponic systems. They help tackle certain pests around the roots, including fungus gnat eggs and larvae, harmful nematodes and root lice in hydroponic growing.

For fungus gnats, treating the growing medium helps address the stages hidden beneath the surface. Removing the visible flies alone can leave the next generation developing in the pot.

The right approach depends on which pest you’ve found and how you grow your plants. If you’re unsure, have a chat with us before choosing a treatment.

How do you use Bio Granules?

In soil and coco, sprinkle one tablespoon of Bio Granules over each pot, cover with 1 cm of growing medium and water in, with or without nutrients.

For preventative use, mix one tablespoon per pot into the growing medium before potting up.

In hydroponic systems, use approximately one tablespoon per plant, secured inside nylon mesh and suspended in the nutrient reservoir.

Always follow the current pack instructions for your setup. Ask us if you’re unsure which application is suitable.

Give your plants the right conditions too

Pest management works best as part of your normal plant care.

Water according to each plant’s needs, check drainage and remove fallen leaves from around pots. Where the plant tolerates it, letting the compost surface dry between waterings can help make conditions less favourable for fungus gnats.

Take extra care with seedlings and fresh cuttings. They need suitable moisture, so avoid drying them out simply to tackle flies.

Check new plants before placing them alongside your existing collection, and keep pots, trays and growing areas tidy.

Need a hand identifying the problem?

You don’t need to know every pest by name before asking for help.

If you’ve noticed flies around your pots or suspect something is affecting the roots, have a chat with us. Tell us which growing medium you use and what you’ve spotted.

You can order A.R.T.S Bio Granules at GHEDirect, or pop into The Greenhouse Effect in Milton Keynes. We’ll help you work out whether they suit your plants and growing setup.