sand and fungus gnats

[dash]

I've heard that putting a layer of sand over the soil will suffocate the fungus gnat larva and hence eliminate a fungus gnat problem. The question I have is how thick of a layer do you need? An inch? two inches? a fingernail deep? Any one have experience with this?

 

[sproutco]

drench with bt

http://www.icmag.com/ic/showthread.php?t=14218&highlight=sand+fungus+gnat

 

[dash]

thanks sproutco, I hadn't seen that thread b4. But I didn't see anything about dt, what is dt short for?

 

[sproutco]

Biological: Bacillus thuringiensis subspecies israelensis (Bti) (Gnatrol)

Comments: A naturally occurring, spore-forming bacterium produced commercially by fermentation. Bti applied at labeled rates provides temporary control and is toxic only to fly larvae, such as mosquitoes, black flies, and fungus gnats. Repeat applications commonly are needed for long-term control. This Bt is a different subspecies from that applied to foliage to control caterpillars. Bt labeled for caterpillars is not effective against fly larvae.

If you don't find gnatrol, you can use bt in mosquito control available at home depot or similar. All this is safe for you and your plants. I would not worry too much about the gnats unless there is a large population feeding on the roots.

 

[dash]

and is it safe to use on clones in rockwool?

 

[sproutco]

Probably. Its only a bacteria.

 

[dash]

well, I'm not as worried about the plants as I am the clones. since I have seen first hand the little larval bastards eating my babies.

 

[dash]

is this the same DT that was outlawed?

 

[inflorescence]

This is BT, Not DDT.

If you suffocate the gnats that would also suffocate your soil. Allow your soil (medium) to breathe. Even when grown in a water medium, we must allow the medium to breathe. Roots need O2.

 

[jaykush]

1/4 inch is fine. jsut make it a nice even layer.

 

[inflorescence]

1/4 inch is fine. jsut make it a nice even layer.

But why risk the lower O2 exchange when there is an easily purchased bacteria available that ONLY kills gnats and their close relatives?

 

[jaykush]

im not one to buy something when i can fix it cheaper myself. my plants grow just as good and when there gone if you MUST take the sand off. its no biggie really.

 

[dash]

I must either be a bit lexdisic or a bit stoned, I thought sproutco wrote dt. But I went and gotsome mosquito plunks(apparently the same thingas dunks but smaller and in a water disolving pouch) and threw one into a gallon of water. Now just gotta gie it time to disolve and then those bastards are gonna DIE!!! thanks everyone

 

[dash]

well Jay, I would have had to buy something either way, as I have no sand on hand.

 

[vonforne]

I went to home Depot and bought some play sand. Skim off a little soil and cover evenly with sand. The adults only last a few days and the larve will die off from suffocation. it takes about 1-2 weeks. I watered from the bottom as to keep the surface dry. They never returned. i think they came from the peat. So, I changed brands.