for preventing fruit flies, etc. I have heard you can use rocks or a layer of sand at the surface. Anyone had experience with this? Fruit flies seem to love living in the dead Long-fibered sphagnum that I use (even though I used a fresh batch less than 2 weeks ago ). Also, does a coat of live sphagnum at the top of the pot keep pests from coming through the top of the pot?
Thanks for your help.