Walking down the pest control product aisle in the hardware store or garden center gives me a headache. Sure, I know bugs in the garden and yard can cause trouble, but that doesn't mean we need to wage full out, heavy duty chemical warfare. It's easy to make up homemade bug spray for the yard and garden that use plant compounds and soap to knock back your bugs.
These sprays can still cause trouble for beneficial insects, too, so use them sparingly, and they shouldn't be put directly on plant parts you want to eat. Use care in handling, washing hand after use and avoiding inhaling the sprays or rubbing them in you eyes. Although they are natural pesticides, they are still irritants. Wash your produce before using.
These DIY bug sprays work best on soft bodied insects like aphids, spider mites, thrips, and the eggs, larval and nymph stages of other garden pests such as squash bugs and cabbage worms. They may also get rid of adult insects with hard shells, but they tend to be more resistant and require repeated applications. This brews are best used within a day or two, or stored in the refrigerator for up to two weeks.
Rhubarb Leaf Garden Bug Spray
Most of us know that you eat the stalks, not the leaves, of rhubarb, because the leaves are too high in oxalic acid. An overdose of oxalic acid can make you sick or even kill you. (Seriously, do not cook up a mess of rhubarb leaves as a green veggie. The British government suggested people eat rhubarb leaves during WWI due to food shortages, and people died.) How much is enough to kill you? Rhubarbinfo.com states:
For a person about 145 pounds (65.7 kg) that's about 25 grams of pure oxalic acid required to cause death. Rhubarb leaves are probably around 0.5% oxalic acid, so that you would need to eat quite a large serving of leaves, like 5 kg (11 lbs), to get that 24 grams of oxalic acid. Note that it will only require a fraction of that to cause sickness.
So, don't eat rhubarb leaves or this bug spray, wash your hands after use and your veggies before eating if you sprayed it anywhere nearby.
- 4 rhubarb leaves, chopped
- 1 quart water
- squirt of dish soap (optional)
Place chopped rhubarb and water in a glass or stainless steel pot. Simmer for about 20 -30 minutes. Strain and cool. I let this settle for an hour or so and then poured off the top to avoid any sediment, but you could also strain it through some cheesecloth or a flour sack towel. Just keep in mind that chunks may clog your spray bottle. Add a squirt of dish soap (this makes it so the spray penetrates the bug skin better – gross but true). Mix well. Place in spray bottle and apply directly on target insects.
Garlic Oil Garden Bug Spray
This oil based spray is a little longer lasting than a water based spray, because it won't dry up so quickly on the leaves. It's adapted from Rodale's All-New Encyclopedia of Organic Gardening, which has a ton of gardening ideas. This is similar to the pest control recipe in 6 Ways to Use Garlic in the Garden, but more concentrated and less stinky.
- 10-15 garlic cloves, chopped
- 1 pint of mineral oil
- Squirt of dish soap, optional
- Water, optional
Place chopped garlic cloves and mineral oil in a glass jar. Let steep for at least 24 hours (longer is fine if you don't get to it right away). Strain. Use as is, or add an equal amount of water and few drops of dish soap.
Onion Scrap Garden Bug Spray
As I explained in the post, “Don't Cry Over Cut Onions“, onions take up sulfur from the soil as they grow, which accounts for their pungent aroma. When they are cut and exposed to oxygen, the sulfur compounds in the onion react to form sulfenic acid, a mild acidic gas. We can use this to our advantage by saving up our chopped onion ends and peels (or cutting up a whole onion if you like) and using them to fight garden pests.
- Onion parts, about 1 cup
- Water, about 1 pint (enough to cover onion bits in a glass jar)
Save up your onion scraps in a sealed container. (The longer they sit, the more powerful the smell will get.) Once you have enough bits, cover them in water, close your container, and allow to steep for 5-7 days. Strain and apply to target insects.
Fight Your Garden Pests from the Inside Out With Healthier Plants!
I have said this before but it needs to be repeated – healthier plants have less bug problems! My friend, Phil, gets into this in more detail in the post, “How to Organically Get Rid of Garden Pests, Forever“.
I see it in my garden every season. When plants get stressed, bugs show up. It's like putting out a casting call for wee garden beasties. If the plants get some TLC (or weather conditions improve), a few bugs may stay around, but they cause little damage. If the plants continue to stay stressed, the bugs multiply and can wipe out entire crops. (Yes, sometimes I have garden failures, too. Drought and heavy rains have no respect for your level of gardening enthusiasm.)
Some of my favorite plant TLC options include:
- Dramm Fish Fertilizer (foliar feed)
- Effective Microorganisms (foliar feed)
- Blackstap Molasses (to feed the effective microorganisms)
- Heavy duty hose end sprayer to apply the above fertilizers
- Worm Castings (can use as a side dressing for established plants)
Bee friendly yards and gardens are also friendly for beneficial insects, who can be a huge help in the garden by eating the guys that cause the trouble. Learn more about creating habitat for the good guys in the post “5 Tips for a Bee Friendly Yard“. Check out The Gardener's Bug Book to help you identify the good and the bad bugs in your garden, and learn other methods of bug control.
Have any homemade bug spray recipes that you'd like to share? Please leave a comment below. Many herbs can help provide safe bug control for just pennies. I know I'm only scratching the surface with this post.
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