Homemade insecticidal soap has been used for centuries in the homeowners battle to control pest and bugs on plants. Over a century ago fish-oil soap was a common solution.
“Natural control” of pest is not something new in today’s green, eco-friendly world.
What Makes An Insect Soap Work
Some people believe there is a secret to mixing soap in water and spraying a plant. Somehow, this helps wash the bugs away. Nope! A good blast of water can wash bugs away.
The secret (if there is one) is in the “soap” used to make the pesticide soap. The soap needs to be a true soap and not a detergent – more on recommended soaps later.
The insecticidal power – the kill – comes from the fatty acids contained in the soap.
The fatty acids are effective against soft bodied insects like: aphids, mealybugs, mites, thrips and white flies. The fatty acids dissolve or remove the insects cell membranes and their natural protective waxy coatings, causing death from excess water loss.
Potassium based soaps are the most effective in making a spray to control plant pest. One of the most well known potassium based soap products available is probably Safer’s Insecticidal Soap, which controls many pests found on houseplants, vegetables and fruit. I myself like to use Neem oil for plants.
Advantages of Garden Soap
- When made and used correctly, they are Eco-Friendly to people, plants, animals and the environment
- No residual effect
- Works on soft bodied insects like: aphids, mealybugs, mites, thrips when coming in direct contact
- Biodegradable and non toxic (right soap required!)
- Safe for beneficial insects, bees, etc
How To Make Insecticidal Soap
Though there are garden soaps available to control insects, you can make your own effective homemade insecticidal soap inexpensively.
Dish washing detergent is made for dishes so don’t grab the liquid dish washing soap. Also, the right soap is key.
The Soap – You want the real thing, pure soap which has the active ingredient of fatty acids – the bug dissolver! Try to get a liquid to make mixing easier.
Look for an all natural pure soap, like Dr. Bronner’s Pure Castile Soap which can be found in many grocery stores or your local natural-foods market. The soap should have no synthetic chemicals, degreasers or skin moisturizers. Naphtha soap is also recommended by many.
The Water – Use Pure Water, distilled is good. If your tap water is good you can use it, but if you have hard water you may want to use a bottled water.
The Sprayer – A clean bottle sprayer (1 quart) or a garden sprayer will work. It really depends on how much you need to apply. DO NOT USE a weed killer sprayer!
The Insecticidal Soap Mix:
You are aiming for 2% soap solution:
For a 1 Gallon Solution:
Mix in 1 gallon of water 5 tablespoons of soap
For a 1 Quart Solution:
Mix in 1 quart of water 1 tablespoon of soap
There always seems to be variations in any homemade recipes or home-brewed formulas calling for more or less of some component.
Two fundamentals which seem to be consistent in any of the various home-brewed insecticide formulas is that stinky or hot tasting ingredients make the best additions.
Cayenne pepper, red pepper, garlic, powerful herbs and extracts, cider vinegar and even a cooking oil.
There are no “set formulas”, this is all trial and error. What works for one may not work for someone else.
The rates below are all for 1 gallon of spray mix:
The Bug Chaser: Garlic or Pepper – Add 1 teaspoon of garlic and/or ground red pepper.
Powdery Mildew: Vinegar – 1 Teaspoon of cider vinegar
Make Spray Stick Longer: Cooking Oil – Add two tablespoons of light cooking oil – corn, olive, grapeseed, canola, or safflower.
Learn and Observe
A Word Of Caution: Learn, Observe and Always Test!
Some spays can do some serious damage to foliage. Always do a test spray in a small area. If the spray is too strong – dilute.
Try reducing the mix rate to a 1% solution if the spray concentrate is too harsh. A 1% solution is what is found in most commercial sprays if you read the label. However, remember a diluted solution may be easier on the plants but less effective.
While you are outdoors, keep your eyes peeled for plants which do not seem to be bothered by insects… they could even be weeds near by. You never know… blending some up to make some type of spray could be the new ingredient you’ve been looking for.
How To Tips On Applying Insecticidal Soap
- Before spraying make sure the soap solution rate has been tested – see above
- Check the weather… Don’t spray on rainy days.
- For best results apply spray early in the day before 9:00 am or late in the afternoon after 5:00 pm, this allows the spray material to be more effective by staying wet longer on the plant.
- Shake well to keep the spray solution mixed and agitated well just before applying. Keep shaking as needed. If solution is allowed to sit, agitate before spraying.
- When applying a pesticide spray, remember the spray is not a residual. The soap spray must cover and wet the pest, not just put a spray drop on the foliage.
- Take the time to completely cover the tops, under sides of leaves and stems with the spray mixture.
- If aphids, mealybugs, or mites are the problem, make sure they get a good coating and they are all wet! The spray is useless once dry.
- Apply to plants which are healthy and well watered. Do not spray plants that are stressed or wilted.
- Avoid spraying tender growth, blooming plants and plants known to be sensitive to soap sprays – ferns, waxy leaf plants, some palms, azaleas, ivy, some vegetables like tomatoes
- Repeat treatment of spray application in a week or so. Many insect problems require a followup applications depending on the severity of the infestation.