Fungus Gnat and Damping-Off Control

Home Remedies for Fungus Gnat and

Damping-Off Control

by Arzeena Hamir

Late winter and early spring is a great

time to start seedlings and get the gardening season

underway. Growing your own seedlings from seed is highly

rewarding and can open doors to even more species that

are not often found in garden centers. However, a couple

of problems can sometimes curb the indoor green thumb

and seriously affect the success of growing seedlings.

Fungus gnats and damping-off are two afflictions that

commonly affect gardeners. However, before you spend

money on expensive chemicals, the solution to these

problems may actually be much more low cost that you


Fungus gnats

 These tiny, black insects seem innocuous

enough as they buzz over your plants. While the adults

rarely cause any problems to plants, if the young larvae

are in large numbers, they can damage your seedlings.

Fungus gnats search out moist soil in which to lay their

eggs. When the eggs hatch, the larvae will feed on the

roots of your plants. Healthy seedlings will often be

able to withstand this feeding but any seedlings that

have small root systems like onions and leeks and those

that are showing symptoms of nutrient stress can be

put back quite significantly.

The easiest way to prevent fungus gnats

is to water your plants properly. Overwatering, which

causes your potting mix to remain moist for extended

periods of time, seems to attract fungus gnats. If your

plants are already infected, allow the soil to dry out

between watering. Alternatively, sprinkle a ¼”

of sand on top of your soil to confuse the adults. Since

the sand drains water quickly, it can sometimes trick

the adults into thinking the soil is dry.

Potting mixes containing peat seem to

be particularly affected by fungus gnats. If the problem

is reoccurring for you, think about switching from a

peat-based mix to one that only contains perlite and

vermiculite. Lastly, if the adult fungus gnats are bothersome,

trap them by making your own sticky trap. The adults

are attracted to the color yellow. Make your own sticky

trap by smearing Vaseline or Tanglefoot on a yellow

surface and hang it up close to where the adults congregate.


Not only will controlling your watering

help to prevent fungus gnats, it will prevent the second

most common problem, damping-off. This condition is

caused by several fungi such as Phtophtora and Pythium.

These fungi live at the soil line, just where air meets

the moist soil surface. When your potting soil is kept

continuously moist by overwatering, the fungi attack

your seedlings. The telltale symptom is a constricted

stem, just at or below the soil surface. Once seedlings

are infected, they tend to fall over at the soil line.

As mentioned, allowing the soil surface

to dry out will go a long way in preventing this problem.

If, for some reason, your potting mix remains wet for

an extended period of time, look to your kitchen cabinet

to help prevent the disease. Cinnamon powder is a natural

fungicide and has been shown to be particularly effective

against damping-off. In addition, Weak chamomile tea

(after it has cooled) is another natural fungicide.

Ensuring seedling success need not be

complicated or expensive. Controlling your watering

and a few home made remedies will go a long way to guaranteeing

healthy seedlings.

Arzeena is an agronomist and gardenwriter

for Organic Living Newsletter. Subscribe to this free

e-newsletter at



Free Garden Catalog


Leave a Reply

Your email address will not be published. Required fields are marked *


This site uses Akismet to reduce spam. Learn how your comment data is processed.