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Fungus gnats attacked seedlings?

Posted by winstella 10b los angeles (My Page) on
Thu, Mar 6, 14 at 12:16

I started these tomatoes from seed less than 2 months ago, and they were doing really well but they got attacked by what I believe to be fungus gnats... I transplanted them outside about a week ago, and they don't seem to be growing much =(

I treated them with spinosad because at first I thought it was thrips... and then last week I treated with neem oil.

What can you tell by the photos? Should I just start over?


Follow-Up Postings:

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RE: Fungus gnats attacked seedlings?

I sure wouldn't start over as they appear to be relatively healthy and capable of recovering assuming proper nutrition and watering.

It can often take plants several weeks to recover from transplant shock depending on the weather, soil temps, and how well they were hardened off prior to transplanting. Larger plants can take longer. So 1 week is no cause for concern.

Fungus gnats are soil dwellers and attracted to soil that is kept overly wet. Any damage done is done to the roots by the larvae Fungus gnats require specific treatments and neither of the ones you used are fungus gnat effective sprayed on the plants. They require a Bt based soil treatment to eliminate them. Mosquito Dunks dissolved in water are commonly used.

Transplanting them will help and simply letting the soil below the surface dry out some eliminates much of the problem.

Dave


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RE: Fungus gnats attacked seedlings?

Ever since the fungus gnats attacked, I've been letting the soil dry out, almost completely when they were in small cups. But there's still SO many of them!!! Another tomato which I started a week after these are still 2 inches tall, I guess because the fungus gnats attacked when they were much younger.

The newer leaves are completely deformed... :( I will try the mosquito dunks. Thanks!!


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RE: Fungus gnats attacked seedlings?

Oh also, I didn't do a traditional hardening off method. I just took all the plants outside on nice days (which was most days here in Los Angeles) and then brought them back in and put them under the light overnight. But the 2 weeks before planting them out, I didn't take them outside because there were so many damn gnats everywhere. I ended up pulling out most of my garden (lettuce and basil) hoping it'd kill some off if they didn't have anything to feed on. I don't think it worked lol.


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RE: Fungus gnats attacked seedlings?

Patience is a virtue !

Considering you didn't hardened them off and transplanted them just a week ago, they are doing just fine ... It will take time for the roots to acclimate and start drawing nutrients.

Looking at the pictures, those plants look better than average to me. They have just right color of green, they are stocky and strong. You have done a superb job.


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RE: Fungus gnats attacked seedlings?

Wow, really? So it doesn't matter that the newer leaves are growing in all disfigured and bumpy?

Yay, that is wonderful to hear. Hopefully I'll be enjoying lots of tomatoes soon! How long do you think it will be from now?? (Plants are approximately 6 weeks old)


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RE: Fungus gnats attacked seedlings?

Those plants look just right to me! I don't see any disfigured new leaves, they kind of look like that at first to me anyway.


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RE: Fungus gnats attacked seedlings?

Oh also, I didn't do a traditional hardening off method. I just took all the plants outside on nice days (which was most days here in Los Angeles) and then brought them back in and put them under the light overnight.

Sorry but that doesn't count as hardening them off. It only stresses the plants more forcing them to readjust to the big difference in environments time and time again. So it will take them longer to recover.

Proper hardening off is vitally important to the long term health of plants so if you have more to do best do it correctly.

Once you eliminate the fungus gnats (assuming that is what they are of course) then the plants should recover - even the ones with the gnarly leaves.

On the other hand make sure that it is actually fungus gnats you are dealing with and not aphids.

When using the Mosquito Dunks just dissolve 1/2 of 1 in 2 gallons of water and use it to lightly water the soil around the base of each plant. Do not spray it on the leaves.

Dave


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RE: Fungus gnats attacked seedlings?

Hopefully I'll be enjoying lots of tomatoes soon! How long do you think it will be from now??
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I could not see any bumps. New growth are bit curly in cooler weather.
When can you get ripe tomatoes ? considering your climate, it all depends on the variety. Do you have any EARLY ones? If yes, I would say in 60 days(from today), if not sooner.
I will plant out mine about 5 weeks from today.

About Fungus gnats: Now that you have them outside it should not be a problem. But if it is still a problem, look into chamomile tea and H2O2(peroxide)


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RE: Fungus gnats attacked seedlings?

Dave- good to know. Will harden them off properly next time. They definitely don't look like aphids... More like flying ants that like to hang out in the soil. It's hard to get a good picture of them.

Seysonn- there's def a lot of bumps! Can you enlarge the photo? I planted red & yellow brandywine, San marzano, cherry, Roma, and sungold but the sungold is the one that hasn't seen any growth for weeks :(. I did try a hydrogen proxide/water solution but it didn't seem to do much.


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RE: Fungus gnats attacked seedlings?

The smoothness of tomato leaves can vary quite a bit from variety to variety and leaf to leaf. Edema (caused by too much water) can also make leaves bumpy -- though I don't recognize any edema spots on your leaves.

Here's a site which features photos of leaves and fruit of different tomato varieties (click to enlarge the photos; some are clearer than others):
http://sev.lternet.edu/~jnekola/Heirloom/tomatoesA.htm
You can also look at leaves of many varieties through this WinterSown page on the Wayback Machine; click to enlarge the photos:
http://web.archive.org/web/20111214025949/http://wintersown.org/wseo1/Tomato_Leaf_Scans.html

As digdirt said, make sure you have fungus gnats rather than aphids. Aphids will be found under leaves and on the newest foliage, busily sucking the juice out of your plants. The aphids which attack tomatoes are usually green, pink, white, or black (IIRC). It is normal to see different sizes in the same group, also both winged and wingless aphids.

This post was edited by missingtheobvious on Thu, Mar 6, 14 at 17:34


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RE: Fungus gnats attacked seedlings?

They look fine to me.

It's 100% normal for transplants to sit and apparently do nothing for a week or more. They are establishing a good root system.


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RE: Fungus gnats attacked seedlings?

Here is a picture of the bug.. I don't have a macro lens so it's hard to take a closeup of something so small.


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RE: Fungus gnats attacked seedlings?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Thu, Mar 6, 14 at 17:37

What's the soil made of and how are you fertilizing?

Al


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RE: Fungus gnats attacked seedlings?

Also, I don't think moving them outside will solve the problem :( they are outside by the hundreds... perhaps I used to overwater my container plants. I have stopped watering as much and I also installed a drip irrigation system so now that the rain has passed, if these are fungus gnats, hopefully they will go away??


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RE: Fungus gnats attacked seedlings?

This is my first time gardening so I am trying different soils in each container. The one that is filling my largest container where most of the bugs seems to hang out at is a mixture of:

miracle grow moisure control
patio plus premium potting mix
organic plus potting mix

Not for any scientific reason whatsoever, just because I didn't realize how much soil would be needed to fill the container so I put everything I had into it ha! It recently sprouted mushrooms after the rain so I know it has alot of organic material, right?

I'm using miracle grow tomato fruit and vegetable fertilizer, until it gets larger,, then I will switch to something with less nitrogen.

I also added grounded up egg shells, asprin & banana peels. Forgot to bury them while I was planting, so I just sprinkled on top.


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RE: Fungus gnats attacked seedlings?

wow, thanks for the link missingtheobvious! after looking at the photos, it seems like they are supposed to be somewhat bumpy. I was panicking because the first few sets of leaves were completely smooth, but as the bumpier leaves came in, it coincided with the bug invasion... maybe everything is okay! haha. I have never grown tomatoes, nor seen a full grown tomato plant in person so don't know what to expect!


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RE: Fungus gnats attacked seedlings?

I can't promise that's a fungus gnat, but wood is not a normal location to find aphids, and their body shape is different.

Then again, here's a winged "green" peach aphid with a skinnier body type:
http://entoplp.okstate.edu/ddd/insects/greenpeachaphid.htm
Aphids do have different shapes and sizes in different stages of their growth, and the winged ones may look very different.

So the important question is whether they congregate on the undersides of your tomato leaves and the new growth. If yes, probably aphids.


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RE: Fungus gnats attacked seedlings?

No, I see none of those fat yellow things sucking under the leaves... I typically find them hanging out in the soil and they are so annoying. They do sometimes crawl on my wooden container and that is where I chose to take the photos because it's nearly impossible to distinguish them from the soil in a photograph.


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RE: Fungus gnats attacked seedlings?

That looks awfully large for a fungus gnat. But there is nothing in the photo for scale so no way to know for sure.

It is clearly some sort of fly but there are 1000s of varieties of them.

Fungus gnats can be seen crawling up out from the soil if you look closely but they are very small like most members of the gnat family.

Like Al I have some concerns about the appearance of the mix in your beds/containers but that is a whole other discussion and many more details would be required. Plus it is too late to do anything about it now for this season since you have already planted.

Dave


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RE: Fungus gnats attacked seedlings?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Thu, Mar 6, 14 at 19:06

Yes - soil choice, watering habits, and your nutritional supplementation form 3 sides of a triangle that has a major impact on how well your plants perform. Each is inextricably linked to the other.

One thing I can tell you is, if we're looking at a planter box instead of a raised bed, you should be very careful to avoid over-watering. Test the dampness of the soil deep in the container, especially while plantings are immature and much of the soil uncolonized by roots. Use a 5/16" wooden dowel sharpened in a pencil sharpener pushed deep in the soil. If it's wet or even damp on removal, you needn't water yet. Soggy soils have great impact on a plant's ability to take up water and the nutrients dissolved in it, so soggy soils can upset your plant's nutritional uptake, even if nutrients are in the soil in the right ratio and in soluble form. Soggy soils are also very unfriendly to root health and function, both of which you really need to guard judiciously - a healthy plant is impossible w/o a healthy root system.

Al


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RE: Fungus gnats attacked seedlings?

Those plants look beautiful to me. Are they the ones you think are distorted or do you have some that look worse? I wouldn't add magic things like aspirin and banana peels and egg shells. Banana peels will bring fruit flies, but your insect looks too long for a fruit fly.


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RE: Fungus gnats attacked seedlings?

They're not large... if you look closely at the wood, you can see the grains- the photo is magnified. They do like to crawl in and out of the soil.

Thanks- I guess I have just never seen tomato plants before.. I thought the leaves were supposed to be uniform and flat! I'm happy to hear they are doing well


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RE: Fungus gnats attacked seedlings?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Thu, Mar 6, 14 at 21:30

Good point - when it comes to container media the focus should be about the medium's structure - not about its ability to feed the plant. Getting proper nutrition to container plants is monkey easy, and things that are rotting - like banana peels and other soil amendments that break down quickly should be avoided. Container growing is an entirely different animal than growing in the garden. There are actually more differences between the two decidedly different forms of culture than similarities. You might want to consider hanging out for awhile on the container gardening forum, as well as here.

I'll leave you a couple of links that will be helpful. The first one is something that should give you a better idea about how important soil choice is to the rewards you get for your efforts.

The second one will help you get a feel for supplemental nutrition for plants in containers. I hope you find them helpful.

Al


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RE: Fungus gnats attacked seedlings?

More like flying ants that like to hang out in the soil.
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ABOUT THE INSECTS:

You mentioned "Flying Ants". Probably you are right. They are also called "Carpenter Ants". I see some holes in the lower wood, which could be drilled/chewed up by carpenter ants. If that scenario is correct, then they are not going to do any harm to your plant BUT they will chew up the wood. Check and see if they are coming out of the wood and returning into it. They cause damage similar to termite.
They could also be winged termite. See the picture


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RE: Fungus gnats attacked seedlings?

When I get gnat problem indoors I found that is very effective way to get rid of them is with yellow sticky traps (sold by park seed and amazon). They work for the flying ones. And the ones in soil... as everybody said above just need to keep soil surface dry.
But once plants get transplanted outdoors seems like Mother Nature takes care of them.
Good luck.


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RE: Fungus gnats attacked seedlings?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Fri, Mar 7, 14 at 15:28

The best way to be rid of fungus gnats is to use a soil they don't favor and keep your tendency to over-water under control.

Al


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RE: Fungus gnats attacked seedlings?

I have dealt with termites and carpenter ants, as well as fungus gnats. No way are those termites or carpenter ants, which are huge compared to fungus gnats, and they are easy to photograph. Dave (digdirt) had the specific remedy for fungus gnats, which is using a soil drench containing mosquito dunks (which contain BT, that kills their larva). And Al (tapla) pointed out that they require wet potting medium with organic matter to survive. Use a fast draining media, and water properly, and you will prevent them. If they show up, use mosquito dunks and let the top of your potting mix dry out between waterings.


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RE: Fungus gnats attacked seedlings?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Fri, Mar 7, 14 at 18:57

Agree - definitely not ants or termites.

Al


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RE: Fungus gnats attacked seedlings?

Just be sure that the Bt (Bacillus thuringiensis) you use is B. thuringiensis israelensis rather than B. thuringiensis kurstaki.

Bt kurstaki (Btk) kills many types of true caterpillars (true caterpillars are those which turn into butterflies or moths). It is not a contact poison, but must be ingested by the larvae.

Bt israelensis (Bti) kills mosquito larvae, fungus gnat larvae, and black fly larvae. It is not a contact poison, but must be ingested by the larvae.


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RE: Fungus gnats attacked seedlings?

I just did a google search.
Even if you had fungal gnats indoor, now that your plants are outside and getting established, gnats should not pose any dame to them. Gnats are mainly indoor small seedlings problem.
The simplest way to combat them is to keep the soil on top dry and mulched with things like gravel, bark,Turface/ DE. This way you will cut their access to -and - from the roots.


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RE: Fungus gnats attacked seedlings?

  • Posted by socalgal USDA z10 Sunset z24, (My Page) on
    Mon, Mar 10, 14 at 12:21

It is quite possible to have fungus gnats in outdoor potted plants in zone 10; I've had plenty. The right type of Bt works really well to get rid of them, with yellow sticky traps to monitor the effectiveness. I've never had them near plants planted in the ground.


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RE: Fungus gnats attacked seedlings?

Good to know socalgal... the gnats are definitely alive and thriving in my outdoor containers. Just checked this morning and there are so many, they're even on my cement now wtf.

another possibility is that a ton of review on miracle grow moisture control mention gnats...perhaps I'm having the same problem because of the mgmc.

On another note, two of my tomato plants that are planted in miracle gro moisture control are doing amazingly better than the other 3 (one in all patio plus organic), the other two in a mix of 3 different plants... the miracle gro plants are now twice as big as the other ones and look much healthier. What a difference. The other 3 plants are also flowering (I pruned them), while the two in miracle gro have not. Interesting.


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RE: Fungus gnats attacked seedlings?

reviews on mgmc: http://www.consumeraffairs.com/homeowners/miracle_gro.html


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RE: Fungus gnats attacked seedlings?

Just checked this morning and there are so many, they're even on my cement now wtf.
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Because they are there does not necessarily mean that they are causing any harm.

Fungal gnats feed on tiny roots of seedlings that are fairly hallow. If your plants' roots are buried ,say 5" deep, the gnats are not going to go that deep, eat and come out and go back again. Even if they did, some good mulch around the plants will cut off their access or make it unattractive.


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RE: Fungus gnats attacked seedlings?

Yes, I have read that, and my larger outdoor plants seem to be okay- however, the pepper plants and the sun gold that I started a week later than the first batch haven't grown at all. The outdoor plants are growing normally now, whilst my sungold is still like 3 inches tall. =(

I just went to buy some bti... opted for Mosquito Bits rather than the dunks because it was a larger can rather than 2 dunks. Also picked up some yellow traps. Hopefully this will help! I have gnats all over my house now, it is so annoying.


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RE: Fungus gnats attacked seedlings?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Wed, Mar 12, 14 at 14:55

Fungus gnats can attack living roots, but their primary diet is decaying organic matter. Gnats aren't so much a problem in and of themselves - more like a symptom of an underlying problem related to soil, watering habits, and often your choice of fertilizer. Organic materials that break down quickly in soils, along with soils that remain excessively moist, will send gnats into an orgiastic breeding frenzy.

Al


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RE: Fungus gnats attacked seedlings?

"Fungus gnats can attack living roots, but their primary diet is decaying organic matter"

Yes, and peat and bark are decaying organic matter. They love peat the most!
Peat and bark have been used in potting mixes mostly because they are light, and keep transportation costs down. A movement for better soils is going on and more and more high end soil are including compost of some sort. Worm castings, etc. Mostly via the organic movement in gardening. The problem I have with peat and bark is that they dry out so quickly. I use them still, think they are excellent products. I amend soils to make it stay moist longer, such as worm castings and other organic material. This is working a lot better for me. I guess new gardeners might tend to over water and these peat/bark mixes may be better for them. But for the experienced gardener they are not that helpful.

This post was edited by Drew51 on Sat, Mar 15, 14 at 16:12


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RE: Fungus gnats attacked seedlings?

Fungus gnats are easily gotten rid of.
They live most of their lives under the soil first as eggs and then as larvae feeding on plant roots and debris in the soil. They emerge as flies to mate and lay eggs in the soil and the cycle continues. You can spray for the flies but it won't help. You have to get to the root of the problem and that's under the soil.

Mix a 1/2 teaspoon of insecticidal soap in a quart of water . Give the container a shake and water the plants--the soil not the plant itself. The soap kills the eggs and larvae and your problem is solved. If you have a large problem with them you may have to do it again but usually one treatments is all that's needed


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RE: Fungus gnats attacked seedlings?

winstella: you sure this isn't what you got? Though I never see them in the soil, just all over my adult tomato plants. I may be off base.

If so, we can talk. :)

Kevin

Here is a link that might be useful: Cyrtopeltis modesta (tomato suck bug)


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RE: Fungus gnats attacked seedlings?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Sat, Mar 15, 14 at 16:50

Peat and bark break down relatively slowly, so neither are high on the list of FG's favorites. They like things that break down quickly - things like the various meals that might be used as soil amendments or fertilizers (feather meal, horn meal, cottonseed meal, alfalfa meal, fish emulsion, compost - especially unfinished compost, green leaves that fall on the soil surface, ..... The banana peels and membrane/albumen residues from the eggshells the OP used would also be particularly attractive as they progress through the putrefaction cycle.

"A movement for better soils is going on and more and more high end soil are including compost of some sort."

Right. Where might we find info on this new movement? You make a lot of statements with authority enough that people might be led to believe you have some degree of experience in certain areas, but we know you talk with that same authority when the topic involves things you have no experience with. That makes it very difficult to take what you say at face value - at least for me. What is a high end soil - an expensive one?

Al


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RE: Fungus gnats attacked seedlings?

  • Posted by flo9 10 (My Page) on
    Sat, Mar 15, 14 at 22:49

For gnats.. like some mentioned to use the yellow sticky traps.

For the gnats deep into the soil there's a product that kills and prevents them... the sticky traps are used for the eggs that hatch and also ones already flying around. I forget what it is called... I just know Lowes and Home Depot doesn't carry it when I was looking to buy it a couple years ago when I had a problem.

I'll try to figure out what it's called and get back to you all when I do. It's organic and not a pesticide and doesn't hurt the roots or plants. I think it's white colored.


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RE: Fungus gnats attacked seedlings?

So... one week after treating with bti and adding yellow sticky traps, I do feel like the population has lessened some what... but definitely hasn't totally disappeared. I can't be completely sure they even lessened because it's been too hot to spend much time outside (91 degrees yesterday ugh)

Here's what a I caught on one of the sticky traps:

Those are 1 inch x 1 inch squares.

What do you think...? I'm still thinking they're fungus gnats.


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RE: Fungus gnats attacked seedlings?

Sure look like fungus gnats to me. Honestly, even if some are still around, I don't think they are able to hurt your plants at this stage. I think it's more likely that the problems you are having now are related more to fertilizing and soil choice. Also, they have had a lot of stress with several different pesticides, not hardening off properly and being transplanted.

What are you feeding them? You said: ... the miracle gro plants are now twice as big as the other ones and look much healthier. What a difference. The other 3 plants are also flowering (I pruned them), while the two in miracle gro have not. Miracle Gro has some fertilizer in it, though not enough to last through the season. It may be the nitrogen in the MiracleGro that is causing some of what you see. Plants that are getting too much nitrogen can grow bigger and greener but fail to produce flowers. Plants that aren't getting enough nutrients can fail to grow.


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RE: Fungus gnats attacked seedlings?

They are all being fed with mg tomato fertilizer.

My question now is if I installed drip irrigation, and the fertilizer is in solid pellet form... How do I fertilize? I've been water w the hose whenever I fertilize :/. Also bought fish emulsion which also needs to be added w the hose and an attachment.


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RE: Fungus gnats attacked seedlings?

Fungus gnats are a pain, i know.
Best way i found is to interrupt the life cycle.
Hitting the adults and larvea at the same time.
BT and yellow stickys should do it, but i would probably either increase the density of BT, or use it more often when you water.

you can make your own stickys too.
and while they do like yellow, they also climb over everything, so if you have some vasoline, you could really put some on some sticks, or just about anything and lay on top of the soil just pickup before waterings, or rain.

i might try to move that yellow sticky closer to the ground as well

you can even set out a few bowls of water with 1 drop of soap in it, the gnats will climb and fall into it, not able to get out.

Outside, natural predators should find them soon, and reporduce


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RE: Fungus gnats attacked seedlings?

I have used chamomile tea for years. Just recently learned that cinnamon is even better. Sprinkle the powder or spray the tea. It should drive the gnats nuts.lol

Making your own sticky tape is easy. Brush some syrup on the yellow paper.


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RE: Fungus gnats attacked seedlings?

Don't use syrup for your sticky tape unless you want ants to crash the party.


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RE: Fungus gnats attacked seedlings?

Agree about the syrup. Vasoline, motor oil, or tanglefoot will suffice. If you want the sticky cards usable over and again, put clear plastic over them(ziploc bag), then spread the substance. When it fills with corpses, remove plastic and start over.

Kevin


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RE: Fungus gnats attacked seedlings?

Just wanted to give an update---- after treating all my plants with bti, my two seedlings are finally seeing growth! Fungus gnats aren't gone by any means but I am just happy the baby plants are growing after weeks and weeks of doing nothing.

The two plants that weren't growing so well in the mixture of soils is finally seeming to grow! Yay! I believe the problem was with fertilizer. After adding fish emulsion & a lot of mg tomato fertilizer, they seem to be much happier in just a week. The other two plants in 100% mg moisture control are huge, perhaps 5-6 times larger than the others plants, all of the same age. Unfortunately I planted them too close together and the leaves are touching so I will expect disease later in the season and plant further apart next time.

I leave for vacation next week, so I'm excited to see what will happen in the 2 weeks that I'll be gone. Will update. I will def do another fish emulsion treatment before I leave.

Weather in SoCal has been amazing. :)

Btw I have been pinching off all the flowers and suckers off every plant, big or small. Should I start leaving the flowers on the larger plants? They're about a foot and a half tall now, not exactly huge but I wouldn't mind getting some tomatoes first ;)


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