I admit, growing an organic garden is not easy! I have battled flea beetles, tomato hornworms, aphid infestations, powdery mildew and cut worms. I've used organic pest control solutions that work and several that absolutely did not. Below are a few recipes that have worked for me.
Recipe from Extremely Green
Naturally occurring compounds in neem oil discourage feeding on treated plants. When ingested, neem disrupts the molting and reproductive cycles of many insects. (In tests, desert locusts, which are voracious herbivores, will sooner starve to death than eat plants treated with neem). Neem has proven remarkably non-toxic to birds, mammals, and beneficial predators like ladybugs, spiders, bees, and wasps.
Mix 1 tsp (cap full) per quart of water (4 tsp per gal) plus 1/4 tsp of liquid dish soap per quart of water (1 tsp per gal). The liquid dish soap acts as an "emulsifier" or "sticker-spreader". Shake well.
Spray the diluted solution generously on all leaf surfaces, including the undersides of leaves. This solution can also be used to water the plants. Use once every 2-4 weeks. Apply early morning or later afternoon.
Garlic Oil Spray
Recipe from Organic Gardening
Organic gardeners have long relied on garlic as part of their pest-fighting arsenal. Garlic contains sulfur, which, besides being toxic to pests, is also an antibacterial and antifungal agent. The dish soap in this mixture also breaks down the bodies of soft-bodied pests, such as aphids.
What You'll Need:
Three to four cloves of garlic
Strainer or cheesecloth
Liquid dish soap
To make garlic oil spray, mince or finely chop three to four cloves of garlic, and add them to two teaspoons of mineral oil. Let this mixture sit for 24 hours. Strain out the garlic pieces, and add the remaining liquid to one pint of water. Add one teaspoon of liquid dish soap. This mixture can be stored and diluted as needed. When you need to spray, use two tablespoons of the mixture added to one pint of water in a spray bottle.
To use your garlic oil spray, first test by spraying an inconspicuous part of the plant to see if your mixture harms it at all. If there are no signs of yellowing or other leaf damage after a day or two, it is safe to use. If there is leaf damage, dilute the mixture with more water and try the test again. Once you have determined that it won't harm your plant, spray the entire plant, paying special attention to the undersides of leaves.
Warning: Garlic oil is a non-selective insecticide, which means that it will kill beneficial insects (such as lady bugs, who are natural predators of aphids) just as easily as it kills the bad guys. It's best to keep as many beneficials around as possible. This spray should only be used if you haven't seen any beneficial bugs in your garden.
from Love to know Organic
Aphids: Sunflowers, Oregano, Coriander,Chives
Cabbage Worms: Tomatoes, Thyme
from Gardens Ablaze
Flea Beetle: Catnip, Garlic, Mint, Sage, Tansy, Wormwood
Nematode: Calendula, Marigold
Snails: Fennel, Garlic, Rosemary
Tomato Hornworm: Dill, Borage, Calendula, Marigold, Petunia, Opal Basil
Whitefly: Basil, Marigold, Oregano, Peppermint, Thyme, Wormwood