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Make Your Own Organic Oil Soap Garden Spray

Neem oil spray

My daughter Britta has definitely emerged as the gardening guru in our family. Today she’s sharing with us her homemade organic fungicide that is just as effective and much cheaper than the commercial alternatives and won’t hurt the environment, our pets, or our families. Way to go Britta!

Britta writes……….   As a gardener in Utah, I love the month of September because the days are a bit cooler and I am still harvesting delicious garden produce throughout the month. However, September in this climate also means the arrival of an insidious and persistent fungal disease you may be familiar with… powdery mildew. *Cue dramatic music.*

Neem Oil

Powdery mildew is a fungus that flourishes when the days are warm, the nights are cool, and dew forms on the foliage of the plants. The fungus tends to affect plants that are crowded and receive poor air circulation, such as cucumber, squash, and melons. Unfortunately for me, Utah autumns provide the perfect growing conditions for powdery mildew, and this year is no exception. It has exploded on several of my plants, killing many of the leaves and leaving me scrambling to find an effective treatment.

At first I read that applying milk diluted with water can help kill the powdery mildew. I tried that, but it didn’t seem to do all that much. About a week later, I was in the Garden Center of a local grocery store looking for snail bait, and happened to see a bottle of Neem Oil Spray. This caught my attention immediately, because I was already somewhat familiar with neem oil after using it to make my own body wash in the past. The Neem Oil Spray bottle said it was a natural fungicide and insecticide, suitable for organic gardening. I was getting a little desperate for a solution to my mildew problem at this point, so I shelled out the $9 for the bottle and went up to my garden to give it a try.

Neem Oil

I can honestly say I was shocked by how well the spray worked against the mildew! It seemed to literally melt the powdery substance away right before my eyes. As I had several plants that were struggling with the fungus, I ended up using the whole bottle of Neem Oil Spray in one go. I was so excited to have found a natural fungicide that worked, but I was not thrilled with the idea of shelling out the money for another bottle! Remembering that I already had a little bottle of neem oil at home, I decided I would find out how to make my own spray. As it turns out, it is very easy to make a great DIY version of this spray!

Neem Oil

DIY Organic Pesticide Spray

Neem Oil

Add all the ingredients to a 24 – 32 oz spray bottle and shake well to combine. This spray will lose its effectiveness quickly, so make a fresh batch for each application. Apply as a treatment for fungal infections and insect infestations such as aphids. Apply once a week to treat existing problems, and once every two weeks for prevention and maintenance.

As for the DIY spray, it worked every bit as well as the store-bought stuff, and continuing to make my own will save me a TON of money in the long-run. How’s that for a win-win?? :-)

Neem Oil

Other Ways to Use Neem Oil

In addition to being useful in the garden, neem oil is also great to have around the house for a number of reasons. Studies have shown that neem shampoos can be used as an effective treatment for head lice. To make a neem shampoo for treating lice, simply mix 1/2 to 1 tsp of neem oil with 8 oz of your preferred shampoo. This treatment can be used both to treat and prevent lice. For pet owners, substituting the shampoo with dog shampoo will make a great treatment to use on dogs with fleas or other itchy skin conditions too!

For humans with itchy skin conditions, 1/2 tsp of neem oil can be added to 8 oz of lotion or body butter to soothe dry, itchy, or irritated skin. Try adding several drops of an essential oil like Lavender or Sandalwood to help mask the yucky neem smell.

Jill Nystul Photo

Jill Nystul (aka Jillee)

Jill Nystul is an accomplished writer and author who founded the blog One Good Thing by Jillee in 2011. With over 30 years of experience in homemaking, she has become a trusted resource for contemporary homemakers by offering practical solutions to everyday household challenges.
I share creative homemaking and lifestyle solutions that make your life easier and more enjoyable!

About Jillee

Jill Nystul

Jill’s 30 years of homemaking experience, make her the trusted source for practical household solutions.

About Jillee

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    • I did some research for you! It will work on a black spot, particularly on roses. It is not harmful to bees as long as you don’t spray it directly on them, so try to apply it in the morning or evening so that it’s dry while the bees are active!

  • Hi Jillee, I found this info on Neem oil at Wikipedia:

    Studies done when Azadirachtin (the primary active pesticidal ingredient in neem oil) was approved as a pesticide showed that when neem leaves were fed to male albino rats for 11 weeks, 100% (reversible) infertility resulted.[6]

    Neem oil and other neem products such as neem leaves and neem tea should not be consumed by pregnant women, women trying to conceive, or children.

  • Good to know. I rarely buy the manufactured solutions because 1. they are expensive & 2. I never know if they really work.
    This is a great post! I did a cost analysis based on a quick net search. Neem Oil (1 oz bottle $6), Castille Soap (16 oz bottle $7), Water?. Neem Oil 2 tsp = 1/3rd of bottle =$2+ Castille Soap 1 tsp=1/96th of bottle=.07 so bottom line $2.07. That’s nearly $7 savings! Ka ching! Thank You, Come Again!

  • You mentioned neem oil in your regular shampoo would help prevent lice, but that the spray for the plants would loose it’s effectiveness quickly. Would it be ok to put the neem oil in the kids shampoo and use it on a regular basis to keep lice at bay or will it loose effectiveness after a while in the bottle? Thank you for this enlightening post!

  • Wow, Britta! Thank you. I’m trying to start my first “real” garden (at age almost 70 ;). I am retired and on a fixed income. This is such a better way to go than $9.00 a pop for the commercial stuff.

    Good job!

  • Wow, what a co-incidence. Last week I went through the same problem. My rosemary had powdery mildew. I mixed a tsp of neem powder in approx 2 cup water and let it sit for couple of hrs. Then sprayed the solution on the rosemary plant. Ta Da…..no more powdery mildew. Neem tree is a versatile tree. In fact, there is no part of the tree without any benefit. There are toothpastes and soaps made from Neem.

    • Lorraine, I used a 24oz bottle so I just filled it to the top with water after adding the other ingredients. You could use a slightly smaller or larger bottle as well without changing the ratios. :-)

      • thank you Britta will try this. you and your mum are awesome i really love this site have a lovely day

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