Greetings from Abingdon and the Grow Your Own program.  This is Deni Peterson, former program manager, here to talk about water pH and its effect on Pyrethrins, commonly used insecticide for organic growers.

Each season, I reeducate myself on a whole list of seasonal “to do’s” and this spring, I came up with an “ah – ha” moment that I thought I’d share.

Safer Soap photo

I was reading a bottle of Safer’s Soap with Pyrethrins to review mixing rates when I read an interesting fact:

safer inside label

Do not use this product in water with pH values above 8.0 unless a buffer solution is added to water. 

I went to my bottle of Pyganic…

pyganic label

And inside the label it also stated:

pyganic inside label

IMPORTANT: It is recommended that spray mix be adjusted to a pH OF 5.5 TO 7.0.  Outside of this range, Pyrethrins degrade and the product will lose its effectiveness. 

AH – HA!

My mind raced to the hot tub, where I had recently changed the water.  Wait, a HOT TUB you ask?  YES! I say… after leaning over all day farming, this back deserves a hot bubble.

Using my handy pH test kit for our spa, I was able to confirm that water, from our tap, which comes from the County Water System, consistently reads over 8.0 pH

Test kit

ph kit empty

Test kit with tap water

ph kit with high ph

SO, how do I amend this situation?  By using VINEGAR!  By simply adding 1 T of vinegar to each gallon of water, you can reduce the pH into the proper acid range to be more effective.

Test kit with vinegar added

ph kit with vinegar added

Now, not everyone has water coming from a municipal source.  Water comes from a lot of places, but it might be worth a test strip to see where it is so you too can get the most effective use of your Pyrethrin sprays when necessary.

Remember, always use caution when applying a Pyrethrin spray.  Safety first!  Spray late in the afternoon, after the sun has set so that our beneficial pollinators are not harmed.  Avoid spraying when wind is present.  Measure your chemicals and add the proper amount of water.  Mix in a clean bucket and pour into your sprayer.  Use gloves and protective clothing that gets washed when you’re done spraying.  And always, wash your hands, face and body (if you can) after spraying.  Take a shower and thank your back for another long day!

Till next time,