Hello fellow GC'ers! Hopefully this will help some of you. Before I get started, let's remember that "the best cure is prevention." But, if you're reading this, chances are you're already freaking out and it's too late. So we'll briefly touch the topic of prevention in a moment! So, one morning you wake up and decide to walk into your grow room, open your cab, or maybe your PC case, to see how your precious little gems are doing. After stepping into your room or opening your cab, suddenly a nearly microscopic UFO flies frantically past your face. Uh oh! So you shove your face into your plant to investigate. Out of the corner of your eye you see movement, and immediately look down towards the surface of the soil. There are creepy crawlies everywhere. Red alert! Code Blue! DEFCON level 5! Calm down, these are just fungus gnats, and you can regain control rather easily. Most posts I see suggest covering the surface of soil with 1/2" of sand or with perlite. My issue with this method, is that if there are eggs, larvae, or pupae living in the soil, watering through the sand/perlite would theoretically still keep them alive as they feed on organic material. Once they mature, they're probably just crawling around as opposed to flying. So you may not see the problem, but it could still be there. My personal method: It's cheap, it's easy, and it's organic. I use this in my vegetable garden, as these little c*cksuckers seem to love tomato plants as well. You will need: • One Gallon Container • A good, clean spray bottle • Dr. Bronner's Liquid Castile Soap (substitute - dawn dish soap) • Olive / Vegetable Oil • Ground Cayenne Pepper • Garlic Powder You can find the Castile Soap at Target, CVS, and also on Amazon. It's great stuff, you can use it for cleaning nearly anything. The scent doesn't particularly matter, but Peppermint may be even more effective for keeping bugs away. Castile soap is organic - I can't comment on Dawn. Steps: 1. Pour one tablespoon of Liquid Castile Soap into your empty gallon container. 2. Add one tablespoon of olive or vegetable oil 3. Add one teaspoon of ground cayenne pepper 4. Try not to sneeze 5. Add one teaspoon of garlic powder 6. Fill container with water. Stir or shake to ensure it's mixed thoroughly. You can do two things with this mixture. 1. Spray Bottle - Pour it into a GOOD spray bottle (the small cheap ones tend to get clogged by the pepper). THOROUGHLY spray your plants with this solution. Spray the top and underneath side of the leaves, spray the stems, spray everything. If you see a gnat flying around, spray it too - and watch it crash and burn. Spray every single one of them you see, they practically die instantly. Stir up the surface of the soil and spray the soil surface as well, as some larvae / pupae may be moving around here. If you are in flower you may want to be more careful, as spraying anything on a flowering plant is discouraged in the interest of mold prevention. Read below for a flowering plant. 2. Use this mixture as a soil drench. Not only will spraying the adult gnats (the one's that fly) kill them, but any eggs, larvae, or pupae in the soil should be killed by this drench as well. I used this solution to spray my tomato plants nearly every day for about two weeks when I had a full blown infestation. I made it rain peppery soapy garlic goodness on these plants, and there were zero side effects - same goes for the girls, too. When things were bad, I used the soil drench for three watering's in a row, and everything was fine. A Bit About Fungus Gnats: Fungus gnats are small flies that infest soil, potting mix (bagged soils), other container media, and other sources of organic decomposition. Their larvae primarily feed on fungi and organic matter in soil, but also chew roots and can be a problem in greenhouses, nurseries, and potted plants. Adult fungus gnats may emerge from houseplants indoors and become a nuisance. They love moist soil, as it is a great place for them to lay their eggs (another reason to NOT overwater). Fungus gnats develop through four stages—egg, larva, pupa, and adult. The tiny eggs and oblong pupae occur in damp organic media where females lay eggs and larvae feed. At 75ºF, eggs hatch in about 3 days, the larvae take approximately 10 days to develop into pupae, and about 4 days later the adults emerge. A generation of fungus gnats (from female to female) can be produced in about 17 days depending upon temperature. The warmer it is, the faster they will develop and the more generations will be produced. With this knowledge of their life cycle, I use the above drench and stay on patrol for at least two weeks. I only spray as needed, as the adults are usually dead within a few days of my initial spraying. From there on, my primary focus is ending their life cycle, ensuring that any of them, at any pre-adult stage that still remain in the soil, cannot mature any further. Additional Tactics: In addition to spraying and drenching, there are a couple other methods I use to effectively take these suckers out quickly. Apple Cider Vinegar: In a small bowl, pour in a generous amount of vinegar. Add a few drops of dish soap. The smell of the ACV attracts the gnats, while the dish soap breaks the surface tension, causing the gnats to fall in and drown. Yellow Sticky Traps: Pretty self explanatory. They are attracted to the color, go to investigate, and are left to their sticky doom. I read of someone coating yellow tops of Planter's peanuts with petroleum jelly and vegetable oil and hanging them as a DIY sticky trap. In any case, hang these all around your room. Fans: You can place additional fans or turn up your fan speed to blow the fungus gnats away from the plants and off of the soil surface. Perhaps even place some sticky traps where you'll be blowing them into! By employing all of these methods, they don't stand much of a chance. The spraying, vinegar, and sticky traps are the first things you should do immediately. This will effectively remove the adult population, halting any further egg production. Then, focus on the soil and drenching to eliminate any remaining forms of this pest that lurk under the surface. Additionally, another approach are "Mosquito Dunks" or "Mosquito Bits" formulated with BTI, or "bacillus thuringiensis israelensis," a bacteria used as a biological control agent for larvae stages of certain dipterans (flies). BTI produces toxins which are effective in killing various species of mosquitoes, fungus gnats, and blackflies, while having almost no effect on other organisms. It is naturally occurring, and research has shown no adverse effects in mammals who have been exposed to this bacteria for prolonged periods of time. Fellow growers have reported using one half to one whole Mosquito "Dunk" by crumbling it into a 5 gallon container of water and using it to water their plants. It has been reported to be quite effective, however, I still remain skeptical of it's usage. I have done well without it, so far! HTH! EDIT: It was brought to my attention that in my original post (in my over-enthusiastic story) I had been describing both fungus gnats and spider mites. This post isn't about spider mites, but it's worth noting that the above spray solution did effectively kill the spider mites, as well as their eggs, that were on my tomato plants - and those things were everywhere. Fungus gnats should only be found flying around in the grow space, or crawling in/on the soil - not under the leaves of the plant.
I think you're describing spider mites and fungus gnats. Fungus gnats don't make white spots on the leaves and they don't appear as black specks under the leaves - spider mites do. Adult fungus gnats fly and resemble fruit flies and do not pose any threat to your leaves or plant - it's the eggs they lay in the soil that's the problem.
Lol. I think the part about u explaining finding these gnats pretty much matches with what actually happened with me. I tried neem treatment, organic pesticides, yellow stickers, ne powder and what not. Finally diatomaceious earth worked for me. Eithet that or the gnats forgot how to mate and multiply. And true, these fuckers like tomato plants as well as my busy beans plants as well. Sent from my Moto G (5) Plus using Tapatalk
You are indeed correct sir! I suppose my tomato plants were being attacked by spider mites while they were also being swarmed with gnats. This is what happens when you type a story while In any case, this solution did also kill the spider mites. I'll edit the post so people don't come to the wrong determination with a gnat/mite problem.