Fungus gnats and coco coir

Teag

Well-Known Member
Can I get some recommendations for dealing with fungus gnats in coco coir
 

Attachments

  • 20210812_120431.jpg
    20210812_120431.jpg
    806.8 KB · Views: 36
Don't keep it so wet, so often. Skipping a watering here n there helps with that.

A hydrogen peroxide flush will wipe out the larvae you might be currently dealing with, i use the 3% and dilute it 4 to 1 with distilled water. Lots of runoff, skip a day, & if the plants show no ill problems do it again. Then back on your fertigation schedule.
 
Don't keep it so wet, so often. Skipping a watering here n there helps with that.

A hydrogen peroxide flush will wipe out the larvae you might be currently dealing with, i use the 3% and dilute it 4 to 1 with distilled water. Lots of runoff, skip a day, & if the plants show no ill problems do it again. Then back on your fertigation schedule.
Coco needs to be kept wet. It's hydroponic, so that's not helpful there.

I used spinosad added to one feed for my outdoors. Pretty much completely wiped them out.
 
I ALWAYS get fungus gnats in coco, it just happens anytime you feed 2 or more times per day. A lot of people have had good success with nematodes, and I'm going to try those next grow, but just mixing up a regular strength neem oil spray and spraying the surface of the pots daily for a week seems to wipe most of them out for me.
 
Sticky traps large square ones cut in half and place on top of medium. Place whole sticky traps on tent floor. Hang 2 sticky traps around canopy level or at light level by tent adjustable rope clips. Medium drench with neem oil concentrate. That'll kill eggs the traps will catch adults. I grow in organic soil with organic amendments. I start every grow with sticky traps. Best to be preventative. Nematodes as mentioned will work as well just a little more expensive and they'll just eat the larva, will still need sticky traps for adults.

I also keep a indoor worm bin me and gnats are sworn enemies lol
 
I ALWAYS get fungus gnats in coco, it just happens anytime you feed 2 or more times per day. A lot of people have had good success with nematodes, and I'm going to try those next grow, but just mixing up a regular strength neem oil spray and spraying the surface of the pots daily for a week seems to wipe most of them out for me.

They always pop up during flower for me. I thought they were fruit flies until this grow.

Had some neem oil on hand so I went ahead and sprayed all the coco.
 
Don't keep it so wet, so often. Skipping a watering here n there helps with that.

A hydrogen peroxide flush will wipe out the larvae you might be currently dealing with, i use the 3% and dilute it 4 to 1 with distilled water. Lots of runoff, skip a day, & if the plants show no ill problems do it again. Then back on your fertigation schedule.

If I don't water twice a day during flower I will get salt build up. They are only in 1 gallon pots as well. If I used RO water instead of tap water then I might be able to get away with this.
 
Fungus gnats in coco in my personal opinion and experience, is due to keeping it too wet too often.

Good luck though, hope u figure it out. Tried to help.
 
Sticky traps for adults.

Mosquito dunks crushed and soaked for an hour or so. I use a gallon jug. Fill with water and shake jug occasionally. Then strain out all the solids to make a fungus gnat soup that can be added to my res.

Takes a couple weeks to eliminate.

20210407_142227.jpg

Dry coco is not practical when top feeding multiple times a day.

Ready to use.
 
Last edited:
If you're getting salt build up if you water/feed more than once a day you're not giving enough run off. In coco/soil you should be giving 20% runoff each time when using liquid nutrients
 
Sticky traps for adults.

Mosquito dunks crushed and soaked for an hour or so. I use a gallon jug. Fill with water and shake jug occasionally. Then strain out all the solids to make a fungus gnat soup that can be added to my res.

Takes a couple weeks to eliminate.

View attachment 4984777

Dry coco is not practical when top feeding multiple times a day.

Ready to use.

Thanks Tint! I'll give it a try. Do you only use this when you see gnats pop up or as a preventative as well?
What is the dosage?
 
Thanks Tint! I'll give it a try. Do you only use this when you see gnats pop up or as a preventative as well?
What is the dosage?
Only if I see gnats show up on sticky traps.

My res is only 8 gallons. Starting with a gallon of that I use 2 dunks to make 1 gallon of soup.

I want to try the microbe lift. No dicking with dunks. Super easy to add to res.
Local Homey depot has lowest price on dunks I've found.
 
If you're using liquid nutrients it's a preventative measure to keep nutrient build up and salts down. How long have you been growing this is common knowledge
It's a lot easier to prevent buildup by not feeding at like 2.5 EC.

I don't think my current outdoor plants have had runoff in weeks.
 
When I used liquid nutrients I went off this scale I didn't use ec. Never became toxic using that scale. Some plants can take more but it's a good scale to go off of for beginner's. Y'all can troll all you'd like this is common knowledge. Not just from me but every old school coco grower on grasscity. I've been seeing that suggestion for years for coco. From old heads in the grow game. Actually for the most part alot of y'all give beginner information all beginner growers would be better off joining GC.
 

Attachments

  • 20210827_165943.jpg
    20210827_165943.jpg
    751.1 KB · Views: 38
Back
Top