I just noticed gnats on my smaller plants in the greenhouse.  First time I've seen them.  I know gnats have been discussed extensively on the forum - almost too much.  My plan is to get some sticky traps and some sundews.  If I do that do I still need to do any chemicals into the soil?  Will that hurt the plants?  Thanks..Tony

I killed many gnats with just putting water in a cup by my bright windows. They drink the water and drown. Pretty Simple...LOL    I also killed many by getting Fly strips. I also smeared that sticky stuff from the strip onto some plastic that was covering a window. Got a lot of them with these methods.

Just like Armando, I use the sticky fly tape and the water cup.  Instead, I add apple cider vinegar in the water to attract the gnats.  And keep the cup away from your plants.  Dave started a thread with this stuff you can add to the soil called "Insect Frass" 

http://figs4funforum.websitetoolbox.com/post/insect-frass-7002946?pid=1283640602#post1283640602

Thanks for suggestions.  Jake, these aren't new cuttings.  They are small plants but past that stage.  I put them in the greenhouse mainly because we've been having such cool nights.  Last week we had low temps in the 40's.  It picked up this week and seems warmer.  I just thought the smaller plants would benefit from some more consistent temps and let them grow a bit longer before they slow down for winter.  Thanks