HELP! First time grow. Already beat the gnats and culled my plants, but I’m facing ever surmounting odds!

So I started my first indoor grow using a Vivosun Mylar tent, as well as a 300w LED light with overhead inline ventilation. I keep air circulation with a rotating tower fan, and another smaller fan at the base of the pants. I had a sever infestation of fungus gnats that’s brought my plants down from 6 to 1, but the survivor is looking rough and I’m worried I may have to start over entirely!
My growing medium is fox farms ocean forest, and I use the fox farm fertilizer trio to feed my plants. The soil PH is roughly 6.4-6.8, however the water I’m using is tap and I don’t yet have a PH testing kit. I also recently moved the light further away from the canopy of my plant and switched from a 24-0 to 18-6 light cycle. NOW, the part that scares me the most is that I recently started another seedling in the tent which is about 2-3 weeks old. It is showing signs of crisping and weird discoloration on the leaves. I’ve baked the soil and made sure the gnats are not the problem. Does anybody have any ideas? Please help, I’m trying to grow medicinal marijuana to treat post traumatic stress disorder sustained in the military, so these crops are important to me to get me off the anti depressants and as I live below the poverty line, I can’t afford to throw away resources.
Thank you in advance for reading and helping!
The larger plant is WI FI OG, and currently in a 3 gallon pot, and the smaller plant is chemdawg currently in a solo cup awaiting transplant.

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Just looks like the soil is a little to hot for them but they will grow out of it. Make sure your pots are staying moist in between waterings…you dont want it to dry out completely before you water again. I would adjust your ph of water in as soon as you can. And whenever you can you need to grab a TDS meter(10 bucks) from amazon so you can watch the ppms of your run off. Eventually the plants are going to eat all the nutrients so you will need some to carry them to harvest


Welcome to ILGM forum! You read as much as possible here and you will be growing some killer in no time! If they are in FFOF soil, you shouldn’t feed for around the first 2 months, and definitely get your ph right going in!


Baking your soil won’t keep fungus gnats from moving in.

Fungus gnats are an ongoing problem for any grower in a climate where fungus gnats live. You can kill every fungus gnats in your house but as soon as weather is conducive for fungus gnats to live outside one or more will find their way into your home and reinfect your plants.

You need to come up with a plan to monitor and control the fungus gnats on an ongoing basis. There are many different ways to control them, you just have to be vigilant.

A plan involves treating every pot of soil in your home including any houseplants.

There are many good threads on this forum discussing how to control them and I’m not about to try to recreate all that here, but you need to break the life cycle. You can do that by applying things to the soil that kill the larvae, or keep the soil at the top of your plant dry by bottom feeding/watering, or covering the soil with something like a layer of sand.

You can monitor and kill adults with yellow sticky pads or small cups of liquid with stuff that kills them.

It would take a major infection of fungus gnats to kill your plants. The larvae eat the fungus that is found in the soil, hence the name, and only attack the plant roots after all the fungus has been consumed. Your soil would have had to been full of little white larvae before they would have killed the plants. Once you know how to get rid of them they are easy to kill and control, you just have to keep on top of it.


I’ve been trying to let the soil dry to combat gnats, but is that really all it is you think? Some extreme nutrient burn? How do you think it will effect my harvest?

Hmmm ok. That makes sense. So it seems that the consensus is just that, my plants growing medium is too hot, and it’s causing nutrient burn in weird parts of the leaves?

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I treated the soil with neem oil a couple times but it didn’t have the desired effect. I also put apple cider vinegar with dish soap and sugar in the tent

I bought the soil online and it arrived kind of damp in the bag already, and when I did a little research it seemed that the fox farm ocean forest soil, just like any soil with earthworm castings and things of that nature, is prone to fungus gnats infestation. My infestation wasn’t that bad, and I live in a place where, at least right now, it is very very cold and very very dry. So fungus gnats don’t naturally do well here luckily. I’m just very concerned because the plants started to show signs of stunting and burning and the gnats were the only obvious issue. I had also moved the light farther away and changed the light cycle because my second concern was that if it wasn’t the gnats, that maybe it was too stressed from the light. I had it about 1 foot off the canpopy to start because I read the reviews on my light in particular and it said that it runs cold and the wattage output is a little weaker than listed.

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Thanks you guys for responding! I’m hoping that it is in fact just an abundance of nutrients and that they will grow out of it.

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One of the easiest things to kill the larvae is a product called “mosquito bits”. It is very easy to use, just sprinkle some on the soil, and that’s it. It works for a long time.

That is a big container that my daughter sent me last summer and I barely made a dent.


All good input above. One other factor to consider is your fans. Too much wind can dry out young leaves.

But overall you look pretty good. I’ve cured my gnat problems by pulling back on watering in the past.

Good luck!


It isn’t the medium itself, it is since medium is already charged with nutes and you where feeding also. So no more feeding until around week 7 or 8, then ease them into feedings starting at 1/4 strength and work you way up! Remember the charts you see floating around are suggested amounts for ideal conditions!


Is it really that effective? I’m pretty sure the garden store near me carries them. I’ll be sure to grab it ASAP. Sorry for delayed response, the spam blocker kept me from posting as I’m new.

Got it. That makes more sense. Nutrient burn as I was taught is usually just on the tips or edges of the leaves. So to see HOLES appearing and tears and cuts In the leaves is very alarming.

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This is the chemdawg baby. I just transplanted it, but these were the signs of stress I was seeing In it’s leaves. It’s kind of dark almost black or purple. Are you guys sure it’s not something more grave that I should be concerned about?

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Sand on top helps keep gnats away for me.


Always take pics in natural light or flash, it’s easier to see everything! The really dark leaves are probably from too much N which is why they are “clawing” too! Get us some better pics though. If you move around and do more on the forum it will ease restrictions, just the way it is set up!


Got it. Here are some better pics.

Some of them look like they are in contact with soil, they will need to be removed. Are you foliar feeding, if so when? The Mosquito bits are good for gnats also if they are bad get some yellow sticky pads and food grade DE(diatomaceous earth)! I believe most issues are from overfeeding, might be some environmental and or mechanical damage as well. Do you have a fan blowing on them? What are ph and ppm of water going in?


It looks like you transplanted the plants out of solo cups into bigger pots? The first posting had pictures of three in solo cups, your last posting showed everything in bigger pots. If not, get them transplanted, once the leaves extend past the cup on all sides it’s time to transplant.

At this stage of growth you need to get serious about watering them. Giving them a little water every day doesn’t cut it. You need to start giving your plants a good soaking and water until runoff so you know how much water your plants can hold. Do it slowly since it will run right through the first time. Give each one a quart of water, let it sit for five or ten minutes then repeat. Continuing the routine until you get runoff from every pot assures that all the soil has been wetted.

Soaking the plants will not harm them in any way, you just need to let them dry out before watering again. It will encourage the roots to search out the moisture in the bottom of the pot as is slowly dries out. You probably won’t have to water for 3-5 days. If you look in on your plants several times a day you will notice if the plant begins to wilt from drying out, just give it a good soaking and it will recover right away. If it took 5 days to dry out start watering every 4 days.

The ugly leaves will never recover and can eventually be removed. We are going to get your grow on track and the ugliness behind you.

You say you have the fox farms trio. Do you have a feeding chart from fox farms? It shows the ratios of the various products at each stage of growth. Normally when growing in Ocean Forest you should be able to get into flower before depleting the nutrients in the soil and feeding shouldn’t be required at this stage of growth. I’m am a little concerned about you baking your soil because it will kill things like bacteria and fungus and microbes that are beneficial. Hopefully you didn’t do that to all your soil, if you did you might want to replace the bacteria and fungus using an product that will do so. Fox Farms makes things called Boomerang and Kangaroots, and Microbrew that does that, but they have short shelf lives of 2-3 years. Azos and Mykos are products that do so and last summer I got a sample pack for $10 shipping that would benefit the soil even without baking it first. They might still offer it.

What is the suggested hanging height of your lamp according to your manufacturer? I have a similar “blurple” LED lamp that has 10W diodes (they use less then 2w in practice) like yours. I had some burning and drying out and cal-mag deficiencies like yours show. I was frustrated so I got a professional quality light meter and discovered that right underneath the lights the ppfd (a measure of light that plants can utilize) was excessive. Off to the sides just 10-12 inches the ppfd’s fell right off. I suggest raising the light to its suggested minimum hanging height (mine was 30 inches) and moving the plants off to the side a little. I can tell by how compact your plants are with all the active branching that your plants don’t feel the need to search out the light, they apparently are getting plenty.

I hope there is something in the above information you find helpful in getting you back on track.


I did a little foliar feeding early on with a 6-4-4 npk ratio grow big from fox farm. They do have fans blowing but not directly. The PH I’ve found is 7 and I don’t have the reader to measure my ppms yet,

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