Gnats/DE

[AndyLowSpark]

Is it safe to use Diatomaceous Earth with cannabis? I used a soil/coco blend to start my seeds. I will be switching to coco/perlite to finish things out, but for now I have a minor gnat issue.

 

[Talonxracer]

Use Mosquito Bits https://summitchemical.com/products/mosquito-bits/ to take care of gnat larvae and use DE and yellow sticky traps for the adults.

 

[Shugrows]

Or nematodes. From what I hear de is a pain to work with

 

[Death The Cultivator]

Is it safe to use Diatomaceous Earth with cannabis? I used a soil/coco blend to start my seeds. I will be switching to coco/perlite to finish things out, but for now I have a minor gnat issue.

It is but I wouldn't. It absorbs moisture too easily making it ineffective.

The most effective option would be SF nematodes with a drench every month. Mosquito bits are okay but it takes 2 weeks or so to establish the bacteria for a colony.

Otherwise a layer of clay balls over the medium and ensuring that there are no standing places for water will keep them away.

 

[tronN00dles]

+1 for nematodes. I use Pot Poppers from Amazon that I apply to my medium every 2-4 weeks.

I also keep a teabag (small fabric nursery bag) of mosquito bits/dunks in any bucket or reservoir that might have standing water.

For severe infestations I’ve resorted to peroxide soaks, but I only ever had to do this with houseplants. I’d be iffy on doing it to a cannabis crop, although it saved my houseplants.

good luck!

 

[Death The Cultivator]

+1 for nematodes. I use Pot Poppers from Amazon that I apply to my medium every 2-4 weeks.

I also keep a teabag (small fabric nursery bag) of mosquito bits/dunks in any bucket or reservoir that might have standing water.

For severe infestations I’ve resorted to peroxide soaks, but I only ever had to do this with houseplants. I’d be iffy on doing it to a cannabis crop, although it saved my houseplants.

good luck!

Gotta use horticultural peroxide, OTC stuff is too weak, but can cause phytotoxicity if used too frequently.

 

[tronN00dles]

Gotta use horticultural peroxide, OTC stuff is too weak, but can cause phytotoxicity if used too frequently.

For sure. I use 29% H2O2 from the local hydroponics shop

 

[Capt.Quirk]

Is it safe to use Diatomaceous Earth with cannabis? I used a soil/coco blend to start my seeds. I will be switching to coco/perlite to finish things out, but for now I have a minor gnat issue.

While diatomaceous is safe, you're better off with the Mosquito Bit drench as @Talonxracer suggests. Your minor problem will develop into a big one if you allow the larva to feed on the roots, then emerge only to lay more eggs and keep the cycle going.

 

[Olderfart]

I also recommend Mosquito Bits. I let one dissolve in my watering can so that every watering comes with some. That in combination with sticky traps did the job in my last soil grow. The previous soil grow was shut down due to gnat damage. If they get out of control, the larvae can do a lot of damage to young plants.

I have not tried nematodes - too difficult to source, and a bit pricey for my tastes.

Good luck with it.

 

[Talonxracer]

I have tried nematodes twice, the first time I tried them I don't think they arrived in a viable condition and the yellow sticky traps were all that worked, the second time was actually on the house plants in the rest of the house and the nematodes took care of the issue,,, a 50% success rate sure didn't justify the price.