Tiny flies killing my plants!

I've got seedlings growing indoors, as well as other plants. Some I've had for a couple years.

There are these fruit fly-looking flies, and they're killing many of the plants off quickly. Even rotting out canna plants down to the tuber. They seem to eat a little leaf, then head toward the plant base.

Any idea what they may be, how I got them (I can only assume they came from the soil), and how I can get rid of them?

Except for the part about eating the leaves of your plants I'd suspect fungus gnats--are they little tiny things? They tend to show up when there's too much moisture. I think the larvae in the soil can do some damage to the roots, but chances are the excess water that brought out the gnats did more damage than the gnats themselves. And I don't think the adults eat plants. To get rid of them, I'd cut back on watering and let things dry out a little more in between waterings. Then you can get yellow sticky traps to catch the adults, and get some Bt (like what's in mosquito dunks) and use that for the soil to get rid of the larvae. I think some people have also had success adding some hydrogen peroxide to the water when they're watering.

Thanks. They're not super tiny... about the size of fruit flies or slightly bigger.

They're even more noticable when I do let the soil dry out. They come from within the spaces in the soil.

I think my huge mistake this year was to use 'Garden Soil' for flowers & vegetables instead of the right seed-starting medium.

I've learned so much this year of 'what not to do'.

Regarding the hydrogen peroxide: That won't harm the plants? I never heard of that, but if it's safe, I'll certainly give it a try.

Thanks again!

No it won't, dilute it a bit with water and it's fine (I don't think you have to be really particular about the concentration, everyone seems to use a different amount, I've even seen someone say they used it straight out of the bottle...not sure I'd recommend that, but if you throw a few tablespoons in a gallon of water that ought to be fine). Lots of people use it with seedlings to help prevent damping off, supposedly it can also help your roots if you've overwatered.

I use it straight out of the bottle for damping off. In small amounts of course. Less than a tsp at a time.

Almost everything I planted from seed is dead.

I guess it was a combo of three things:

1. I used MiracleGro vegetable and flower soil instead of potting soil or seed starting mix.

2. Dampening off.

3. Those gnats. There have been times I move a plant container and about 20 of them fly out.

Oh well... live & learn.

Hi kelli, if you still have some plants alive, then take them outside and gently wash all the soil off the roots and wash the stems or dunk them in water too, re-pot them into shop bought compost (IN cleaned pots) and water them from the bottom by sitting the pots in a tray of water till the soil turns darker, then let the pots drain the excess water before you take them inside again, while the plants are outdoors try to either spray the area you have the flies or put up the yellow sticky traps mentioned as they will also help protect you from other aphids that are on the go now, get rid of the fly infested soil you used before as you dont want to get anything else infested by throwing it onto the garden etc. hope this can help you save a few of your plants. good luck. WeeNel.

Sorry your seedlings didn't make it...if it makes you feel any better it's happened to all of us! I suspect it was your soil that was the root of all of those problems--I think that soil was meant for gardens not containers, and garden soil holds too much moisture. That in turn increases your chances of damping off and also when you have soil that stays too wet that's when you tend to get the fungus gnats. So I think if you buy some seed starting mix next time and watch the watering you'll have a lot more success.

Thanks so much for your advice.

It's just sad because they all germinated so quickly, only to die as quickly. We had planted enough of each flower to keep some, give some away, and sell the majority. I had 120 cannas seeded and ended up with only 5 surviving plants.

I went to the garden center yesterday and bought replacements for some of the things that died. But, many that didn't make it were flowers you don't usually find in stores. Fortunately, I had saved the majority of the rare seeds for next year... just incase.

Since it's soooo much soil, what would you think if I threw it in my composter? I don't usually use the composted stuff until it's been in for about 2 years.

Or should I just play it safe & chuck it?