You are here:

House Plants/Gnatrol and Nematodes Sf


Is it safe to use both Gnatrol and Nematodes Sf at the same time?

Hi Martha,

It is not a good idea to use any pesticides with nematodes or any other beneficial insects. Gnatrol is not a pesticide, so it is probably okay to use with nematodes. However, why would you want to? Pick one or the other, try it and see if it works. If it does not, then try the other one. Gnatrol is less expensive and more readily available so that is the logical one to start with. Using both simultaneously provides no added benefit.

Poor soil quality, unnecessary repotting and keeping soil too moist are the primary causes of fungus gnat problems. It is important to address these issues in addition to treating the larvae in the soil. One of the most effective things you can do is to remove all loose surface soil not in immediate contact with roots and discard it. This is where many of the larvae live. In addition, removing the excess soil will allow the soil in the root zone to dry out sooner. Dry soil is the enemy of gnat larvae, so keep the soil as dry as possible.

I have written a detailed article on indoor plant pests that I will email for free to you (or anyone else) who emails a request to me at I have also written an indoor plant care book in a PDF format that I can sell you if you contact me at my email address.

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

If this information has been helpful, please click the Rate Volunteer bar below and enter a rating and NOMINATION for me. I am a volunteer on this site so Ratings are the only compensation I receive for answering plant questions.

Need more information? Visit my website at:
A link to

or email me at or call me at 917-887-8601 (EST)
Will Creed, Interior Landscaper
Horticultural Help, NYC

Visit my website at: A link to

House Plants

All Answers

Answers by Expert:

Ask Experts


Will Creed


I am the only expert in this category with professional hands-on experience and knowledge of all indoor plants. I can answer questions regarding light, water, fertilizer, repotting, pruning and humidity and temperature requirements. I can identify plant pests and provide information on safe, effective treatments. My answers are based on 35 years of professional experience and scientific research and are clear and easy to understand. I do NOT use search engines to find answers to your questions. If you read my previous posts here, you will get a good idea as to how thorough and professional my answers are.


I have over 35 years of professional indoor landscaping experience caring for plants in homes, offices, building lobbies, stores, restaurants, and other adverse environments. I have written extensively on the care of indoor plants, including a 260 page book. My specialties include Ficus trees, low light plants, repotting, pest control, and re-blooming holiday plants. Be sure to check my ratings and nominations to learn why I am the top-rated indoor plant expert. I am the only House Plant expert consistently ranked in the AllExperts Top 20.

BA, Amherst College

©2017 All rights reserved.