I'm new to gardening and this year is my first time planting. I think I have fungus gnats and I read about using soapy water. Does this mean mix up some dish soap in a watering can? What kind of ratio do I use?
Thanks.
- rainbowgardener
- Super Green Thumb
- Posts: 25279
- Joined: Sun Feb 15, 2009 6:04 pm
- Location: TN/GA 7b
Nope, not dish soap. Dishwashing liquid is usually detergent not actual soap. Detergent is very damaging to plants. You need actual soap, which is Ivory, Dr. Brunners, Murphy's oil soap and some others.
But the soapy water spray is good against aphids, whiteflies, scale insects and probably a number of others. I'm not sure that it works against the fungus gnats. Or at least, even if though it would probably do in the adults, I'm pretty sure it won't help against the larvae that are deep in the soil.
Here's a thread we had going about fungus gnat control:
https://www.helpfulgardener.com/forum/viewtopic.php?p=114899&highlight=soapy+water+spray#114899
But the soapy water spray is good against aphids, whiteflies, scale insects and probably a number of others. I'm not sure that it works against the fungus gnats. Or at least, even if though it would probably do in the adults, I'm pretty sure it won't help against the larvae that are deep in the soil.
Here's a thread we had going about fungus gnat control:
https://www.helpfulgardener.com/forum/viewtopic.php?p=114899&highlight=soapy+water+spray#114899
Back to soapy water....
Putting on helmet and ducking here..... It has been common to use Dawn dish soap, well detergent, the original blue one. I put a few drops in a windex style sprayer and spray the leaves. Then I give the plant a shower of clean water from the hose. Whether soap or detergent does help get dust and grime off, also the sticky from scale, and you can rub some of the scales off. (especially on the bay leaves).
Ivory dish liquid is a detergent. I use that when washing yarn, and for hand wash stuff and washing woollens.
Putting on helmet and ducking here..... It has been common to use Dawn dish soap, well detergent, the original blue one. I put a few drops in a windex style sprayer and spray the leaves. Then I give the plant a shower of clean water from the hose. Whether soap or detergent does help get dust and grime off, also the sticky from scale, and you can rub some of the scales off. (especially on the bay leaves).
Ivory dish liquid is a detergent. I use that when washing yarn, and for hand wash stuff and washing woollens.
I killed all the leaves on an entire branch of a tree the first time I used the soapy water treatment for aphids. I made the mixture using Dawn.
Dawn is great stuff. I use it at home, and it's what is used to clean wildlife that have been rescued from oil spills. It's nice and gentle on their skin, while strong enough to cut through the sludge.
But for my plants, I now use Dr. Bronner's Pure Castile Soap.
Dawn is great stuff. I use it at home, and it's what is used to clean wildlife that have been rescued from oil spills. It's nice and gentle on their skin, while strong enough to cut through the sludge.
But for my plants, I now use Dr. Bronner's Pure Castile Soap.

- rainbowgardener
- Super Green Thumb
- Posts: 25279
- Joined: Sun Feb 15, 2009 6:04 pm
- Location: TN/GA 7b
I used shower shampoo for the solution, mixing with crushed garlic and a table spoon of veggi oil. It worked well except for my cherry blossom tree, of which it killed several branches of leaves. In the end I had to cut off the branches affected. But the rest of the tree holds up well. I am still puzzled as to what happened....
I wonder if it is the soapy water, or else that killed the leaves. It did happen right after I applied the solution though.
I wonder if it is the soapy water, or else that killed the leaves. It did happen right after I applied the solution though.
Here's a link to an article on the chemistry of shampoo. It also has links to other "chemistry of ..." articles. Maybe one of them will help describe what happened to the leaves.
https://everyday-chemistry.suite101.com/article.cfm/how_shampoo_works
Cynthia H.
Had to spend 1.5 hours today at the emergency clinic to pick up pain meds...an unfortunately busy Sunday for many dog owners.
Vergil was home with DH; I had "Little Girl" (her nickname), our 10-year-old Bernese, with me for some one-on-one time.
https://everyday-chemistry.suite101.com/article.cfm/how_shampoo_works
Cynthia H.
Had to spend 1.5 hours today at the emergency clinic to pick up pain meds...an unfortunately busy Sunday for many dog owners.
