Question
Hi,

I recently discovered that my fern plant has small worms in the soil. I'm sure it's from new dirt when I repotted it this summer. Not sure how to get rid of them.

While searching my other plants I also discovers a small centipede in another plant.

I'm also noticing small black bugs flying around that I see in the dirt. They're annoying little critters.

So I'm hoping to get rid of the bugs and make sure all my house plants are not infested.

Considering the weather is cold here in NY I need to treat inside...

Can you offer any suggestions or comments?
You advice is appreciated!
Thanks,
Stacy

Thanks for offering advice

Answer
Hi Stacy,

You have more than one kind of pest problem and it is hard to treat them in the same way.

Most indoor plants do not need to be repotted. One of the problems with repotting is that contaminated soil is often used and that introduces pest problems. Another problem is that pots that are too large cause root rot. That's the background information for you.

For the plants that have crawling insects in the soil, submerge them up to the pot rims in a tub or sink filled with plain water. Leave the pot submerged for about 30 minutes. This flooding of the soil will cause the critters to emerge from the soil in search of air.

The flying black bugs are fungus gnats. Adult fungus gnats fly around and are an annoyance, but they are not harmful to people. Each gnat lives for about 5 days. The trick is to get rid of the next generation - the gnat larvae that live in the top layer of the soil. The larvae feed on decaying organic matter. Decaying pine bark in potting mixes and decaying plants roots feed the larvae. Try to keep the soil as dry as possible. Remove all loose soil from the surface and put a light layer of coarse coir (coconut husk) or sand or diatomaceous earth on the soil surface. These substances have sharp edges that carve up the larvae. (Recent studies indicate that fine-textured peat moss also deters gnat larvae.)

Another safe technique is to place ?inch slices of raw potato on the surface of the soil. After a day or so, discard the slices along with the larvae inside. Repeat this until there are no more larvae in the potato.

For more serious infestations try Knock-Out Gnats to treat fungus gnats available from Gardens Alive for about $20. See http://www.gardensalive.com/item_display.asp?ProductNumber=1962

Detection trick: Add a little water to the soil and then look very closely for tiny fungus gnat larvae swimming in the water as it pools on the surface. You need good light and good eyes to see them. If you don't, then your plant is probably gnat free.

Prevention is often the best remedy. Use sterile potting mixes that are free of bark chips. The potting mix should have ample drainage material, such as perlite so that it drains well and allows the soil to dry out frequently. Fungus gnats can nearly always be traced back to overwatering and/or poor soil quality.

To attract and capture the adult flying gnats, pour a little red wine into a small glass (cooking wine will work, if you don't want to waste the good stuff!) and leave it out for the day. Repeat the treatment as necessary.

Please let me know if any of this is unclear or if you have any additional questions.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

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