Saturday, April 28, 2012

Fun with Fungus Gnats

There are tiny black gnats that have been plaguing my plant starts for quite a while now.  I recently learned that they are probably fungus gnats.  These little critters like to eat the fungus that forms on the soil when your plants are a little too moist.  My plants have been too moist because I repotted them in cups and was too lazy to poke some drainage holes in the bottom.  Note to next-year-self...drainage is very GOOD!   I was kind of trying to ignore the gnats, but pretty soon it was hard to.  Whenever I brushed my hands over the plants, they would rise out of nowhere like some sort of locust infestation.

Apparently, fungus gnat larvae love to live in the soil and eat the roots of your plants.  I don't know if they dislike pepper plants, but my peppers are robust and my tomatoes are pathetic.  I've learned that the larvae often come in potting soil.  I thought I was ok buying organic local soil, and organic Roma tomato seeds for the tomatoes that replaced my last ones that died off.  But I think the soil was a bit too organic!  I also wonder if the seed could have had a seedborne virus of some sort.

I've tried many things now in an attempt to resurrect these sad plants and obliterate their foes, but i think the most effective medicine would be prevention through good drainage and getting the little stressed plants transplanted soon.  If you have fungus gnat problems, here's what I tried.

1. cinnamon:  it's an antifungal.  I sprinkled it on the surface of the soil to try to kill the fungus.  It killed all the visible fungus.  I let the surface soil dry in hopes that the fungus gnat larvae would not have a hospitable home.  I kept the house ventilated while I did this because cinnamon seems to like to float in the air.

2. sticky fly tape:  it's yellow and sticky.  flies and gnats land on it and never leave again.  It has caught many adults.  (gnat and person type alike...some of my hair remains forever taped there)

3.  soapy water:  I sprayed soapy water on the leaves of the plants, hoping to make them icky to the gnats.

4.  nutmeg:  nutmeg has insecticidal, fungicidal and antibacterial properties.  I sprinkled this on the soil of the plants.

5. diatomaceous earth:  I sprinkled this only on the plants that were hardening off outside, as it is dangerous to our lungs if we were to breathe it in because it's made of tiny ground fossils of shellfish.

Verdict:  all the hardened off plants were free of fungus gnats when I transplanted them, which leads me to believed that either fresh cool air or the diatomaceous earth were the deciding factors.  The soil certainly wasn't very dry!

Moral of the story and note to my next year self:  Transplant your starts to larger containers before they get stressed, so they are not susceptible to pests.  Transplant them into a very plain, well drained medium, into a container with drainage holes and be sure not to overwater.  Put a fan on your plants as well to encouraged good ventilation and to strengthen your plants.

Hardening off the celery.  There was a downpour, but it didn't care too much.   I need to figure out a different medium for onions next year...and better drainage.  That will be my mantra...drainage, drainage, drainage.
fungus gnat enjoying a nice basil snack. (I don't know if they eat anything besides fungus)

My poor tomatoes.  Spotty, light green leaves.  They have been pink since they sprouted. I wonder if it's the variety of organic Roma seeds I bought at the hardware store.  I wonder if they have some seedborne virus as well?  I was desperate to replace my other tomatoes that were destroyed by the compost I planted them in, so I got these seeds.  

Did you know that cinnamon is antifungal?  This mushroom was growing in with the hollyhocks, and began to shrivel pretty quickly after the cinnamon was sprinkled on it.  
This is for free because it is much cuter and happier than a fungus gnat.
This is also for free because it's adorable.  My girls were completely worn out after the birth of our baby goats and fell asleep on the couch.  

1 comment:

  1. Now all your next year self has to do is remember this blog post is here and look it up!


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