Fighting Fungus, Fungus Gnats, and Whitefly in Your Seedlings

 Starting plants indoors can certainly be more difficult that it sounds. The seedlings become your babies, of a sort, and no doubt you keep going to check on them. I find myself in a state of concern, wanting to water, then thinking I shouldn't have, and it goes around in circles. After a week of following some of the suggestions below, however, things seem to be well under control.

To prevent damping off, where the stem rots near the soil, and other disease, watering must be kept to just as much as is really needed. Since the plants quickly develop a tap root which goes straight down, watering should be from below, letting the starting medium draw it up. Any water left in the tray after fifteen minutes should be poured out. The plants will be hydrated, and they should not be watered again until the soil is good and dry or the plants start to wilt. This will help to prevent fungus from growing and gnat larvae from developing. On the other hand, whitefly likes warm and dry conditions, so it is a juggling act. Don't panic.

The gnats are tiny insects you will see flying around in and near your plants - they look like a tiny mosquito about 3/16th of an inch. Each of them lays about 300 eggs in a week, so for that reason alone, you need to discourage their existence. Their larvae grow for two weeks in wet soil, eating fungus and munching on your plants' roots. Then they fly out to lay 300 eggs each! Whitefly is smaller still, about 1/16th of an inch, with milky white wings. It lays eggs on the underside of a leaf.

What can be done? I alway encourage homeopathy, and as per my article with directions for use, in this case you could use Psorinum or Sulphur. (I did rescue two drooping tomato seedlings today with Arnica after dropping a Goji Berry plant on them not once, but twice. So much for the delicate Goji, however.)

While I am no expert on any of this, I do listen to experts and am here to report to those who might be more inclined to read on a blog than go to YouTube. Many of my readers are from other parts of the world, and perhaps the videos are not available to some. Today I am sharing ways to fight troublesome fungus gnats as related by Brian of Next Level Gardening. Thank you, Brian!

None of these solutions is harmful to the plants, animals (except bugs), or humans.

1) Premoisten your potting soil or seed starting mix with boiling water before using it. This will kill most of the larvae. 

2) Only moisten from below, and use an oscillating fan some to dry the soil and strengthen the stems.

3) Sprinkling cinnamon on top of the soil kills the fungus that feeds the gnats.

4) Mixing diatomaceous earth into the soil will kill the larvae. 

5) Setting out a bowl with apple cider vinegar mixed with a tad of dishsoap attracts and traps the gnats. Brian says you can put it in a jar, cover it with plastic wrap, and cut a slit in the top. That didn't work for my gnats. They were confused about how to get in.

6) You can purchase yellow sticky traps on Amazon; gnats love yellow. Or you can obtain yellow paint chips or other stiff yellow paper and cover it with petroleum jelly, to which they will stick. Sorry gnats, but 300 a week? 

7) You can make a mixture of Neem oil and water per directions on the bottle, soak the soil, and spray the leaves. It's a tad smelly, and the next solution is not, and it is less expensive.

8 Do the same instead with hydrogen peroxide mixed with water. Brian says 1 part hydrogen peroxide to 5 parts of water. Elsewhere I read 1:10. I used 1:5 and had great results. Any extra should be stored in a dark container or in the dark. Both Neem oil and hydrogen peroxide are antifungal (so you won't want to use it in your trees and berries garden, where you are trying to create fungal dominated soil.) Repeat this every few days.

9) Mix Mosquito Bits into the soil; it is made with BT, which has a scientific name that is unpronounceable, but it is safe.

10) Brian said this is ten solutions. I think it was 9 plus my homeopathy. These critters put up a real fight, so you will want to use a combination of some of the above tricks. You have nothing else to do anyway, right?

I had a real problem with fungus gnats, and after a week of using a hydrogen peroxide soak (my favorite, probably the most successful), yellow stickies, and BT, I no longer have fungus gnats flying around. I might be tempted to go with just hydrogen peroxide soaks, twice weekly, for the next trays, and see how that goes. 

Hydrogen peroxide, H2O2, is water with an extra oxygen atom. Oxygen is great for the roots of your plants. Hydrogen peroxide is found in rain water, which is why plants look so perky after a shower. Properly diluted, it is great for your plants. You might see fizzing and bubbling after pouring it in the soil, but that is just oxygen being released.

I do want to add that hydrogen peroxide kills good bacteria as well as bad, and Neem kills SOME good bacteria. So we have to factor that in to our planning, though the plants will be fine during the indoor period. Plants that are put outside while small and young do better at growing up strong than those that are kept inside for a long time; therefore, plan to start them at a time when they can soon be hardened to the sun gradually and moved out to the garden without frost danger. That will help them establish in your good soil, teeming with life, early on.

Please let us know in the comments if you have something more to share on this. Thanks!