Spraying soapy water on plants doesn’t prevent garden bugs from coming to the plant; it kills them if it makes direct contact. If you spray the bugs before they create the next generation of plant chewers, that’s a form of prevention. Yet soapy water has no lasting or wide-ranging effects, so you have to reapply it and spray it directly on the bugs. Homemade soap sprays may harm plants, so always test any preparation for plants on a small area and check for damage the next day before using more of it.
Soap Bug-Control Benefits
Soap kills bugs by messing up their cell metabolism and dissolving the waxy layer that holds in their body moisture. It ends up taking away their vital fluids the way some of them do to your plants. Soap and insecticidal soap have a particular gardening benefit. They are reasonably safe for bees, according to the University of California, Davis, Integrated Pest Management Program. So you can stop pest bugs with soap without killing the beneficial pollinators your garden needs for flowering and fruiting. Always follow product instructions and store them out of reach of children and pets.
The Insecticidal Soap Advantage
When it comes to soap spray to use on bugs, a commercial insecticidal soap may be a wiser choice than making it yourself. Insecticidal soaps are designed to remove the waxy coatings from insects without harming plants, according to Jeff Gillman, author of “The Truth About Garden Remedies.” A homemade soap spray might damage the waxy layer on plant leaves and stems that protects them. This exposes the plant to dehydration and can cause the leaves to become dull, discolored and sunburned. Insecticidal soap is used for many garden pests, including psyllids, glassy-winged sharp shooters, spider mites, whiteflies, thrips, scale and lace bugs.
Prepare for Battle
Arm yourself with a spray bottle, a hat and — if you’re spraying thorny plants — reinforced gloves. If your spray bottle adjusts, use a wide setting, not the skinny stream. You’re out to get them wet, not to dislodge them. They’ll die where they stand. Protective eye goggles or sunglasses help keep ricocheting soap spray and dead bugs out of your eyes. If you do make your own soapy water spray, use 2 percent or less soap to reduce the risk of plant damage, the Colorado State University Extension suggests. That’s no more than 4 teaspoons of soap per quart of water. Test the spray on a leaf and check for damage the next day before applying any more of the spray.
It’s All in the Aim
When it comes to using a soap spray, you’ve got to aim right at the bugs. Shoot the undersides of leaves, the stems and the buds. Those areas are often hangouts for sap-sucking pests such as aphids. Saturate the plant vampires with the spray. Avoid being dripped on by starting at the top of the plant and working your way down. Reapply soap spray as needed. Soap doesn’t repel bugs, so watch the plants for signs of more bugs.
Back when I started my first garden, a certain celebrity gardener and his books of gardening concoctions were all the rage. You could tell when it was fundraising time on our local PBS station because they’d have him live in the studio, telling us that all we had to do was use items such as baby shampoo, instant tea, and whiskey, and we’d be able to grow our best garden ever.
Those claims seemed pretty far-fetched to me back then, and now that I know a little more, I know that several of those concoctions were either just plain bad ideas or that one item in his recipe was the one that was actually doing the work while the rest were either unnecessary or possibly harmful to plants, insects and other soil-dwelling organisms. So please know that my b.s. radar is at high alert when I see anything about homemade gardening sprays and the like. With that in mind, here are 15 homemade, organic solutions for garden problems. I use them, and they work. And not one of them requires you to pour whiskey on your plants.
1.Tomato leaf spray is effective in killing aphids and mites. It works because the alkaloids in the tomato leaves (and the leaves of all nightshades, actually) are fatal to many insects.
2. Garlic oil spray is a great, safe insect repellent. Simply put three to four cloves of minced garlic into two teaspoons of mineral oil. Let the mixture sit overnight, and then strain the garlic out of the oil. Add the oil to one pint of water, and add a teaspoon of biodegradable dish soap. Store in a bottle or jar, and dilute the mixture when you use it by adding two tablespoons of your garlic oil mixture to one pint of water.
This mixture works because the compounds in garlic (namely, diallyl disulfide and diallyl trisulfide) are irritating or deadly to many insects. The oil and soap help the mixture stick to plant leaves. What insects does garlic oil repel? Whiteflies, aphids, and most beetles will avoid plants sprayed with garlic oil. A word of caution: don’t apply this spray on a sunny day, because the oils can cause foliage to burn.
3. Hot pepper spray is a great solution if you have problems with mites. Simply mix two tablespoons of hot pepper sauce, a few drops of biodegradable dish soap, and one quart of water and let it sit overnight. Use a spray bottle to apply the spray to infested plants.
Hot pepper spray works because the compound capsaicin, which causes the "heat" in hot peppers, is just as irritating to insects as it is to us (have you ever sliced a hot pepper and gotten any of it in an open cut? Ouch!) This mixture also helps repel whiteflies, but it may have to be reapplied if you start to see the mites or whiteflies returning.
4. Simple soap spray is useful in taking out a wide variety of garden pests, including aphids, scale, mites, and thrips. Just add one tablespoon of dishwashing soap to a gallon of water and spray the mixture on the pests.
Why does this work? The soap dissolves the outer coating or shell of the insects, eventually killing them.
5. Beer for the slugs. Sink a tuna can or pie plate into the ground, and add a couple of inches of beer, to about an inch below the top of the container. The slugs will go in for a drink and drown. Beer works because the slugs are attracted to the yeast. It’s really important to sink the container into the soil and keep the beer about an inch lower than the soil. This way, the slugs have to go down after the beer, and they drown. If the beer is near the soil, the slugs can just have a drink and then go and munch some hostas when they’re done with happy hour.
6. Citrus rinds as slug traps. This works. If you don’t have beer in the house, but you do have oranges, grapefruits, or lemons, give this a try.
7. Newspaper earwig traps work well for reducing the population of these sometimes-pesky insects.
8. Soda bottle yellowjacket traps work by attracting the yellowjackets away from seating or picnic areas, and then ensuring that they can’t escape the trap.
9. Red pepper spray works well for making your plants less tasty to mammal and bird pests. If bunnies, deer, mice, squirrels, and birds are regularly messing with your garden, make the following mixture and spray target plants weekly. Mix four tablespoons of Tabasco sauce, one quart of water, and one teaspoon of dish soap. The capsaicin in the pepper spray will irritate the animal pests, and they’ll look for less spicy fare elsewhere.
Fungal Disease Solutions
10. Milk for powdery mildew. The milk works just as well as toxic fungicides at preventing the growth of powdery mildew. This mixture will need to be reapplied regularly, but it works wonderfully.
11. Baking soda spray for powdery mildew is a tried-and-true method for preventing powdery mildew. It needs to be applied weekly, but if you have a problem with mildew in your garden, it will be well worth the time. Simply combine one tablespoon of baking soda, one tablespoon of vegetable oil, one tablespoon of dish soap and one gallon of water and spray it on the foliage of susceptible plants. Baking soda spray works because the baking soda disrupts fungal spores, preventing them from germinating. The oil and soap help the mixture stick to plant leaves.
12. Vinegar works very well for weeds in your lawn and garden. The main issue with vinegar is that it can harm other plants. I recommend using a foam paintbrush to brush the vinegar directly onto the leaves of weeds you’re trying to kill. This prevents the vinegar from getting onto other plants and ensures that the entire leaf surface is coated with the vinegar.
13. Boiling water for sidewalk weeds. Boil some water, and pour it over weeds in the cracks of your sidewalks or driveways. Most weeds can’t stand up to this treatment, and your problem is solved. Just be careful when pouring!
14. Vinegar and salt for sidewalk weeds. I personally prefer pouring boiling water on sidewalk weeds, or pulling them. But if you have some really stubborn weeds, you can try diluting a few teaspoons of water into some white vinegar and pouring that onto your sidewalk weeds. Please note that this concoction will kill just about any plant it comes in contact with, so keep it away from your other plants, as well as your lawn.
Best Homemade Garden Concoction of All
15. Compost. Seriously, whether you’re an apartment dweller with a fire escape farm or a rural farmer, you need to be making and using the stuff. It adds nutrients, improves soil structure, increases moisture retention, and increases the number of beneficial microbes in your soil. And that’s all besides preventing organic matter from making its way to the landfill.
I hope these ideas for safe, homemade organic garden concoctions are helpful. By having just a handful of inexpensive items on hand, you can take care of most common gardening dilemmas in your own, green way.
Soap is one effective and inexpensive means of controlling common pests on plants, indoors and outdoors. Unlike many chemical pesticides, these you can use without worrying you are exposing yourself, or the environment, to toxic chemicals. Dish soap sprays are safe for most plants; however oldfashionedliving.com does warn it is unsafe for cauliflower, squash and red cabbage.
Pour 1 cup of sunflower oil or safflower oil in a spray bottle, as suggested by oldfashionedliving.com. The oil helps the soap spray stick to the plant’s foliage. Add 1 cup of water and 2 tbsp. of a mild liquid dish soap.
- Soap is one effective and inexpensive means of controlling common pests on plants, indoors and outdoors.
- Pour 1 cup of sunflower oil or safflower oil in a spray bottle, as suggested by oldfashionedliving.com.
Put the cap on the spray bottle and shake it well to mix the oil and soap. In the early morning or evening ( to prevent sun scald) spray garden plants with the formula. You can also use soap spray on houseplants–in that case you won’t need to worry about the time of day. As long as the plant is away from direct sunlight, spraying is fine.
Spray the tops of the leaves, as well as the undersides where some insects like to hide. Also spray the stems, if necessary (look for insects themselves, or signs of insects such as webbing).
Oisat.org warns you should test the solution on one plant, first, before spraying several. This way you can make sure you won’t harm the plants with the mixture.
- Put the cap on the spray bottle and shake it well to mix the oil and soap.
- Oisat.org warns you should test the solution on one plant, first, before spraying several.
Repeat the application every two weeks, or more frequently–depending on the insect infestation.
Did you know that home gardeners have been using homemade insecticidal soap for a long time? Fish-oil soap used to be the common solution for pest control, but now eco-friendly consumers are turning to all-natural alternatives.
Remember, not all pests are bad. Here are some beneficial insects, good bugs for your garden.
Table of contents
Video on Homemade Insecticidal Soap
What Makes An Insecticide Soap Work
Some people believe there is a pest control secret to mixing soap in water and spraying a plant. Somehow, this helps remove bugs from your garden. Nope! A good blast of water can wash bugs away. The secret (if one exists) is in the “soap” used to make the “insect killer” soap.
Use a true soap, like Dr Bonner’s Castile soap and not a dish detergent or dish soap – more on recommended soaps later. The insect killer power comes from the fatty acids contained in the soap.
The fatty acids work effectively killing soft-bodied insects like aphids, mealybugs, leaf piercing spider mites, thrips, scale insects and whiteflies. These fatty acids dissolve or remove the garden insects cell membranes and their natural protective waxy coatings, causing death from excess water loss.
Potassium salts in the soaps are the most useful in making a spray to control plant pest. One of the most well-known potassium based insecticidal soap spray products is Safer Insecticidal Soap, which controls many plant bug pests found on houseplants, vegetables, and fruit. I like to use Neem oil for plants. Another favorite is Diatomaceous Earth.
Advantages of Garden Horticultural Soap
- When made and used correctly, organic insecticidal soap sprays are Eco-Friendly to people, plants, animals and the environment.
- No residual effect , aphids, spider mites, and thrips (soft-bodied insects) when coming in direct contact
- Biodegradable and nontoxic (right soap required!)
- Safe for beneficial insects, bees, etc
- Perfect for organic gardening and OMRI listed.
How To Make A Homemade Insecticidal Soap Recipe
Though there are garden soaps available to control insect pests, you can make your own effective homemade insecticidal soap inexpensively.
Dishwashing detergent made for dishes may not work. The right soap is key.
- The Soap – You want the real thing, pure soap which includes the active ingredient of fatty acids – the bug dissolver! Try to get a liquid soap to make mixing easier. Look for an all-natural pure soap, like Dr. Bronner’s Pure Castile Soap, found in many grocery stores or local natural-foods markets. The soap should have no synthetic chemicals, degreasers or skin moisturizers. Experienced gardeners also recommend Naphtha soap.
- The Water – Use Pure Water, distilled is good. If your tap water is good use it, but if you have hard water use a bottled water instead.
- The Sprayer – A clean spray bottle (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:
Aim 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
More Insecticidal Soap Recipes and Variations
There are some great variations for homemade insecticidal soap here on WikiHow.com
You’ll always find variations in any homemade recipes or home-brewed formulas calling for more or less of some component. Two consistent fundamentals in any of the various home-brewed insecticide formulas: 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.
No “set formulas” exist, 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 for garden pest control: Learn, Observe and Always Test!
Some spays can do some serious damage to sensitive plant 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.
If you read the label, most commercial insecticidal soap sprays come in a 1% solution. However, remember a diluted solution may be easier on the plants but less effective. While outdoors, look for plants not bothered by insects… even nearby weeds. You never know… blending some up to make some type of spray could be the new ingredient you’ve been looking for.
Any place gardeners gather to talk about plants, there will be talk of soap. Dish soap and water are often referred to as the holy grail for managing insects from aphids to Japanese beetles. Understanding how soap impacts insects and how to best use soaps means better insect management and healthier plants.
How soaps impact (or don’t impact) insects
We still don’t understand exactly how soap kills (or doesn’t kill) an insect. The working theory is that the soap washes off a protective coating on the insect’s body, causing it to dry out.
Because of this potential cause and effect, only certain insects are susceptible; small, soft-bodied insects are those most likely to be controlled. The soapy water covering their bodies apparently causes them to dry out and die.
Soapy water is occasionally effective on larger insects, such as boxelder bugs.
This means that soap is safe for pollinators and natural enemies. As long as you aren’t coating them in the soap, they won’t be bothered.
Soap is a good match with a bucket of water because it breaks the surface tension on the water and causes insects to sink into the water and drown.
Tips for getting the most out of suds
Right spray, right insect.
Soapy water is not a universal insecticide. This is good. It allows us to preserve beneficial insects in the garden. It also means that not every insect will be bothered by soap.
Small, soft-bodied insects are the best candidates for management with soapy water. Aphids, whiteflies, thrips, and mites are all good candidates for soapy water sprays. Sturdy, large-bodied insects like caterpillars and beetles — including Japanese beetles (sorry!) — are unlikely to be affected.
The soapy water needs to not just touch the insect but also coat the insect’s body in order to be effective. This likely means turning over leaves to reach insects on the underside of leaves. A bonus effect is that many of these small-bodied insects will be knocked off the plant if the spray is high pressure, so you get physical and chemical control in one spray.
Timing is everything.
Because soapy water works by touching the insects, sprays need to be made whenever new insect populations appear and start to grow. Spraying soap directly on the leaves when no insects are present does nothing, as soap doesn’t bother insects if they eat it. It only works if it contacts the full body.
Soapy water burning your plants? Head to the store instead of the pantry
Some gardeners purchase ready-to-use insecticidal soaps while others will make their own solutions using dish soap and water. If you are in the latter group, aim for a 2% soap solution: add just 2 teaspoons of dish soap to 1 pint of water.
High concentrations of soap can burn plant foliage, especially when plants are stressed, temperatures are over 90°F and humidity is high. Much of Minnesota has seen many days with afternoon high temperatures of 90°F or greater this summer.
There are commercially available insecticidal soaps formulated to reduce the chances of plant damage. You can by one that you dilute yourself, or something that is ready to use (abbreviated as RTU on some packaging).
Some plants are very sensitive to soapy sprays, and are not good candidates for their use. This list includes hawthorn, sweet pea, cherries and plum, and some gardeners have reported tomato varieties that can also be damaged. If you’re concerned about leaf burn, test on a small area of the plant before making widespread applications.
Bugs invading a garden or flowerbed or munching on a favorite tree, shrub or houseplant don’t necessarily call for a costly pesticide that may raise concerns about human or pet health or populations of beneficial insects. In fact, insecticidal soap, which you can make at home using standard dish soap, can effectively control many soft-bodied plant pests, including aphids, mealybugs, thrips, whiteflies, spider mites and scales.
Things You Will Need
Glass jar with lid
Garden sprayer or spray bottle
Make the Solution
Combine liquid dish soap with water at a ratio of 2 tablespoons per gallon to create a mixture of slightly less than 1 percent soap. Mix together well.
Homemade insecticidal soap doesn’t work effectively if the water is too hard. To test whether water from a certain source is acceptable, combine water and soap in the recommended ratio in a clear glass jar and mix it thoroughly. If a scum forms on the surface of the water, the water is too hard and you must treat it or find an alternative source.
Pour the Mixture
Pour the mixture into a garden sprayer or spray bottle if you prepared it in a different container.
Test for Toxicity
Spray the mixture on a small, inconspicuous section of each plant you wish to treat for insects. Monitor that area for any damage for at least 24 hours and ideally for 48 hours. If no damage is apparent, you can proceed to treat the plant more broadly. If injury does occur, dilute the soap mixture further or choose a different, milder soap.
Spray Affected Plants
In the early morning, spray the affected plants thoroughly with the soap mixture, focusing your efforts on parts of the plant where damaging insects are concentrated, like leaf undersides and leaf axils. Remember that the wet soap must come into direct contact with the pests to control them.
Repeat the Application
Repeat the application every four to seven days until the pests are sufficiently controlled.
Use only a mild liquid dish soap that does not contain a degreaser and is not intended for use with a dishwashing machine.
Although an insect-controlling spray made from dish soap is very low in toxicity, it can still irritate the eyes or cause vomiting or other problems if ingested.
Don’t apply the soap spray to drought-stressed plants or when temperatures are above 90 degrees Fahrenheit.
Dawn detergent is a grease-fighting dish soap that has kept tableware and cutlery sparkling clean since 1973. It is also one of the soaps of choice for homemade insecticides, according to the University of Florida IFAS Extension website. Homemade insecticidal soaps containing Dawn detergent helps control garden pests that attack indoor and outdoor plants without posing a health risk to your family.
Insecticidal soap controls various sap-sucking insects plaguing plants such as aphids, spider mites, whiteflies, mealybugs and scale. These pests feed on the cell content of plants, leading to leaf discoloration, loss of vigor, leaf dropping and stunted growth. Insecticidal soap has a low toxicity level to beneficial insects — such as bees and butterflies — and breaks down in the environment quickly, leaving no residue behind. However, insecticidal soap must directly come in contact with the soft-bodied pests to successfully control them.
Both commercial and homemade insecticidal soaps contain potassium of fatty acids, which dissolves the exoskeleton and disrupts the insect’s cell membrane. Never use automatic dishwasher soap, laundry detergent or dry detergent, according to the University of Florida IFAS Extension website. These products can cause more harm to the plants than the insects you are trying to control.
The recipe for homemade insecticidal soap requires only three ingredients: Dawn dish soap, vegetable oil and soft water. Mix 2.5 tablespoons of the Dawn dish soap and 2.5 tablespoons of vegetable oil with 1 gallon of warm soft water. The Dawn dish soap used in the recipe must not contain bleach, which could harm the plants. Furthermore, you should always use soft water when diluting pesticides. Hard water contains minerals, which interfere with the insecticidal soap, reducing its effectiveness.
To apply the homemade insecticidal soap, you will need to spray the infested plant — undersides and tops of leaves, stems, buds and blooms — thoroughly with the solution. For easier application of the homemade pesticide, transfer the solution to a clean spray bottle or garden sprayer after mixing the ingredients together. Repeat the treatment at 7- to 14-day intervals until you have controlled the soft-bodied, sap-sucking pests.
Never apply insecticidal soap to plants with hairy or waxy leaves, or when temperatures are above 90 degrees Fahrenheit. When in doubt, always test the insecticide on a small portion of the plant’s leaves and wait 24 hours. If no damage to the plant has occurred, continue with the treatment. Furthermore, when treating outdoor plants do so on a calm day to help prevent wind drifts and on a day when no rain is expected for 24 hours after the application.
If you have a vegetable garden, you most likely have aphids, too. The small insect pests, known as “plant lice,” feed off plants by attaching to the leaves or base of the entire plant and suck out the nutrients, causing the plant to wither, yellow or curl at the leaves.
Aphid populations reproduce so quickly that by the time you figure out the problem, they’ve already infested your garden and potentially infected your plants and rose bushes with lethal viruses.
You can fight off these natural predators with a homemade aphid spray, but the question is how to make them yourself. Using something as simple as liquid dish soap, you can get rid of these apex rose killers today.
Homemade Sprays vs. Chemical Sprays
Some people choose to plant gardens full of beneficial fruits and vegetables to feed their families. Using chemical pesticides to remove pests would negate any health benefits hoping to be gained.
Others might plant flowers that they use to create a fragrant home, potentially transferring harmful chemicals from the garden to their home. Numerous natural and organic substances can be mixed to form a natural aphid spray to kill invasive aphids, lace bugs, and parasitic wasps.
Homemade Aphid Spray Recipes
Soap and Water
A few tablespoons of liquid dish or insecticidal soap diluted in a pint of water is the simplest way to make a natural aphid killer spray for that aphid infestation. After mixing the water and soap mixture, fill up a squirt bottle, take a dish sponge and head out to your garden.
Your first thought might be to indiscriminately spray all the plants in your garden with the dish soap spray bottle. However, doing so will kill any beneficial insects along with the aphids.
Instead, to control aphids but not lose your good bugs, spray the soapy water onto the sponge and gently wipe it on the leaves of the plants. Be sure to check underneath the plant leaves for eggs and larvae.
Castile soap is a versatile all-natural, vegetable-based liquid soap with olive and mineral oil as the main ingredients. When combined with vinegar and water, Castile makes a DIY natural aphid spray. The vinegar deters future garden pests from invading your new growth.
Organic Pesticide – Vinegar Aphid Spray Recipe
- 1 tablespoon Castile soap
- 1 tablespoon white vinegar
- 1 gallon of water
Like dishwashing soap, vinegar is lethal to all insects, whether they are the Japanese species of aphids you are trying to get rid of or the good bugs you need in your garden. Use a spray bottle to spray the tops and bottoms of the leaves lightly.
Pure and organic Neem oil can be used to repel aphids, cabbage worms, other pests, as well as help control any fungi they transfer into your garden. Simply mix Neem oil for plants with a few drops of liquid dish soap and fife cups of water.
Neem Oil Based Aphid Spray
- 1 tbsp neem oil
- 1/3 tbsp liquid dish soap
- 5 cups of water
Once you dilute the Neem oil, use a garden hose sprayer to mist your garden with the mixture in the early morning. Neem oil doesn’t have any harmful effects on beneficial insects, but it does help in repelling aphids, mosquitoes, and other pests.
Spray this solution on all your plants, from the tomatoes and cucumbers in the vegetable garden to flowers like roses and milkweed to the base of trees to repel unwanted aphids and other pesky insects. Your plants will thank you for ridding them of these life-sucking creatures!
Essential oils have long been used in aromatherapy but are recently becoming popular in many aspects of the home, including pest control for gardens. A mixture of thyme, peppermint, cloves and rosemary oils create a potent mix that will kill and repel aphids.
If you have outdoor or stray cats who routinely enter your garden, peppermint oil is one of the essential oils that are known to be potentially toxic to cats. On the other hand, cats dislike the scent of rosemary, which can make it a digging deterrent.
Tomato Leaf Spray
Toxic compounds called alkaloids are found in the leaves of tomato plants. These tomato leaves can be chopped, soaked in water overnight, drained and diluted with water in a spray bottle to create a natural aphid killer.
Unless you are allergic to tomatoes, this recipe isn’t dangerous for humans or plants. Directly spray the leaves and undersides of plants in your garden to kill the harmful plant lice.
Garlic Oil Spray
Garlic isn’t just used to repel vampires. The sulfur in garlic is toxic to pests. It also kills ladybugs and other beneficial insects. For that reason, this garlic-based natural aphid spray should only be used if you don’t have any essential bugs in your garden.