DIY - Make your own Permethrin Mosquito Yard Spray

Making your own Permethrin based mosquito spray good up to 30 days – using an Orthro Dial’nSpray and 10% Permethrin solution. I had previously used a Permethrin based spray from Cutter Backyard Free to keep down the mosquitoes in our yard. We are in a heavily wooded area and the commercial Permethrin based hose spray worked well for us. It usually kept the mosquito population to almost 3-4 weeks depending on the amount of rain we had. For the most part this made our yard usable during the summer. These sprays have become difficult to buy, so I figured why not make my own.

As best I can tell Permethrin properly applied is a safe mosquito reduction chemical. So I decided to make my own using commonly available Ortho Dial n spray and 10% Permethrin used for cutting down pest in animal barns. I found the 10% Permethrin for $14.44 from Amazon or (see 8/30/2016 update below for more economical 36.8% Permethrin solution).

I just needed to figure out the proper dilution and delivery rate for the dial n spray. The Permethrin I bought recommended ½ oz of 10% spray for 3 gallons of water to cover 1000 sq ft. I did the math to upsize this to cover 5000 sq. ft. of lawn and fill my Ortho dial n spray (new model) (32 oz capacity).


  • Garden hose and water supply
  • 1 – 32 oz Ortho Dial n Spray
  • 1- 32 oz 10% (or 36.8%) Permethrin solution (any brand)


  • Add 2.5 oz 10% Permethrin in the dial n sprayer container
  • Fill the remainder of the dial n spray with water (creates 32 oz water and Permethrin solution –properly diluted to instructions)
Dial n Spray Setting
fl oz
of Water Mixture
sq ft
yard coverage
per gallon
per gallon
10% 2.5 30 15 5000 2.00 4.00
36.8% 0.7 30 15 5000 2.00 4.00

Set the dial n spray to apply at a rate of 2 oz per gallon. The previous Cutter solution recommended applying the solution when it was wet out. So I usually wet the area before I spray with the hose (no solution). Once it’s wet I spray the solution over the wetted grass, weeds, under our deck, and the shady corners of our porch with the dial n spray set to 2 oz per gallon.

I did my first spray on June 4th and I can tell it’s time to spray again. They were really cut down for the last month. The mosquito population has just started picking up again. Based on the rate of usage I should get 12 applications a year for $15. I think that’s a pretty economical way to enjoy your backyard again.

As with any chemical, be sure to read the directions thoroughly. Be careful in what pesticide you apply and use it sparingly, so as to minimize any impact on the environment.

Hope this blog post makes your backyard more livable for the summer.

UPDATE 2012-06-01:
It would appear that the Ortho Dial n spray design has changed and doesn't work as well as a hose sprayer. The Chapin G362 Professional No Pre-Mix Sprayer seems to get good reviews on Amazon and should work the same way -haven't tried it my dial n spray (old design) is holding up well. It has a 16 ounce container vs the 32 ounce of the Ortho sprayer). To compensate, just set the Chapin model to "4" which delivers 4 tablespoons per gallon.

UPDATE 2016-08-30:
Prices on the 10% solution on Amazon have gotten expensive and many retailers seem to be selling the 36.8% at the same price. Technically that's around 75% less for the same chemical. I would now recommend a quart of the 36.8% Permethrin solution as this seems to be better priced and widely available. Buy whichever is concentration or brand is cheapest. I added the updated dilution rates in the table above (0.7 ounces of 36.8% solution).
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  1. Just sprayed the yard for the first time today. The weather was perfect. Nice rain yesterday and the yard is still damp. Should be bad for the mosquitoes health.

    1. Hi David,
      If the ratio table that you put together is correct then the "Cutter Yard Spray Bottle" will also work.
      5000 sq ft for a 32 ounce bottle would be 2.5 ounces of 10 Permethrin in the Cutter bottle.

  2. 2nd spraying for the year today. Pretty much exactly 6 weeks later, but it's been real dry here. Should at least cut down on the mosquitoes under our deck in the shade.

  3. One last spraying this year. We got some of the remnants of hurricane Isaac (the perfect light misty rain) and this last spraying of Permethrin should kill all the West Nile carrying mosquitoes through the end of summer.

  4. First spray of the 2013 mosquito season. Rain left the yard pretty damp - so it was a good day to spray. Still on my first bottle of Permethrin from 3 years ago...

  5. David, inspired by your blog, I purchased the insectide/Gilmour sprayer. The recommendation on my bottle was 1.5 oz in 10 gallons of water / 1000 sq ft. Also, the Gilmour sprayer only holds 16 oz. Can you help me with the mixtures? I want to get this right. We also have about 5000 sq ft to treat. Many thanks!!

    1. I took a moment to think about how the system works, go figure. Simply knock the sprayer setting down to 2, for your concentration.

    2. I thought about it also... Since the Gilmour sprayer is 1/2 the capacity of the Ortho.

      If you put the full 2.5 ounces of pemetherin in the Gilmour -then set the setting on the Gilmour either to 1 ounce per gallon or 2 tablespoons per gallon. That will then cover the 5,000 square feet at the concentration I use. I think that's what your saying. If you could confirm the setting on the Gilmour sprayer -I'll add it to the table up above for future clarity.

  6. On the Gilmour sprayer, the setting of 2 will deliver 2 tablespoons (1 ounce) per gallon. If you want 1.5 ounces of permethrin per 10 gallons for 1000/sq ft, you'd put 1.5 ounces of permethrin concentrate in the sprayer, dilute until you have 10 ounces and spray this over 1000 sq ft.

    The sprayer will holds up to 16 ounces, however, so if you want to fill up the entire bottle, you'd want to use 2.4 ounces of permethrin concentrate, dilute to 16 ounces, and spray over 1600 square feet. Rounding up to 2.5 ounces seems reasonable, just from a measuring standpoint, but you'd still only want to cover 1600 square feet (i.e., just because you have a stronger solution doesn't mean you should spread it more thinly).

  7. HI David - I found your wisdom invaluable on this subject of Permethrin. I did as you recommended to buy the cheaper of the 2 (36.8%) and the Chapin G362 sprayer. however I do have a question of the ratio (as one measures in tsp & the other in oz) !! -- as a GUESStimate - we did aprx .7 oz in the sprayer jug (NOT diluted at all) -set the sprayer to 4 and sprayed about 1000 sq feet --- Was I right in my math? was I wrong at any point?? YOUR HELP IS GREATLY APPRECIATED!! thanks (ps - I should add - we are in a HEAVILY populated tick, gnat & mosquito territory - can't go outside without getting at least 1 tick!) thanks! Helen

  8. I don't understand why you dilute your permetherin. The recommended application is 0.4 to 0.8 oz. per gallon of water. If you use the chemical at full strength and set the hose end sprayer to 1/2 oz., you are right in this prescribed range.


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