If you are like me, there are two main battles that I fight in growing a vegetable garden: weather and pests.
Weather, we cannot do much about. We take our best guess as to when that last frost will sneak in, and have empty containers and straw on hand to use as protection in case we're wrong. We can water when it's dry, use raised beds if it's getting to be too wet, have sulfur, milk and Neem oil on hand to ward off blight and fungus. But other than growing in the controlled environment of a greenhouse, we cannot control the weather: we just deal with it.
Pests, we have a little more control over. How much control depends on how far we are wiling to go. If we're willing to saturate our food in poisons, we can achieve a high degree of efficiency against insects. I, for one, prefer to avoid poisons that can have a deleterious effect on my family and me. Fortunately, there are other ways.
Here are a few of the things I do in my garden to help ward off insects and other pests.
Rabbits have been a major issue in past years. I tried a perimeter fence around the garden, but used the wrong fencing and they ran right through it to destroy much of my produce. So I built fence boxes for my raised beds from PVC and poultry mesh. These have been very effective in keeping out the rabbits. Not so much against chipmunks and squirrels but, fortunately, these are only a minor concern (so far) because my dogs tend to make them fearful of coming into the yard.
Squash vine borers decimated my zucchini crop last year. Horticulturist Jessica Walliser, author of several gardening books, including “Attracting Beneficial Bugs to Your Garden: A Natural Approach to Pest Control” offers the tip of wrapping a strip of aluminum foil around the base of the plant early in the season to prevent female moths from laying eggs where the plant is most vulnerable. Nestle the foil just below the soil surface, extending it up to the lowermost leaf. As the plant grows, be sure to adjust the foil so it doesn't strangle the growing stem. I'm trying that this year on some of my squash plants. On the rest I'm using Neem oil as an insect repellent and preventative against powdery white mildew: a problem in our humid climate.
To prevent Colorado potato beetles, cover potato plants with a floating row cover immediately after planting and pin the edges of the fabric to the ground with landscape pins or rocks. This keeps the beetles away from the foliage. Just leave the cover in place until harvest because pollination is not an issue. I use the fence box frames and just add a layer of insect netting (or old sheer curtains from the Goodwill) to keep these pesky beetles out.
Cucumber beetles can be a real pest. For small patches, interplant cucumbers with tansy or catnip to fend off cucumber beetles. For large patches, coat the seedling with kaolin clay mixed with water and sprayed on the seedlings. Some large scale growers dip entire flats of seedlings into the mix, which coats the underside better than using a sprayer. You can also trap the adult beetles on yellow sticky cards placed just above the plant tops. Attach cotton balls soaked in clove or bay oil to the cards. These oils contain eugenol, which mimics cucumber beetle pheromone and attracts female beetles that land on the sticky cards and become trapped.
You can thwart cutworms by recycling. Cutworm moths lay eggs in the soil around your plants. The larvae then travel to your plants and “girdle” young plants at soil level. To prevent this, spend the winter saving toilet paper tubes, paper towel tubes, and (maybe) tin cans. When you plant, surround susceptible seeds or seedlings with a 2-inch high collar of paperboard, poking the collar into the ground by 1 inch. This will keep the cutworm larvae away from your plant's delicate young stems. At the end of the growing season, the paperboard collars will compost. Tin cans with the bottoms cut out also work and can be used on large crops like corn. Recycle the cans when the season is over.
Flea beetles are the bane of many potato, tomato, eggplant and radish growers. But flea beetles are easily deterred by covering the plants with a coating of kaolin clay or dusting with diatomaceous earth.
Kaolin clay is a wetable powder that is sprayed on plants, forming a sticky film over the leaves that flea beetles and other pests avoid. Kaolin clay products (such as Surround) are available from local garden centers and various online sources. Diatomaceous earth is made up of the skeletal remains of minuscule sea creatures that lived in colonies when the land was covered with water. This gray power is sprinkled dry onto plants where beetles, ants, and fleas will attack. The dust is very sharp and cuts into the joints of the attackers, causing them to dehydrate and die. A layer of DE on top of the soil where slugs crawl is said to work through their slime and do the same to them. I haven't tried that. DE will attack good bugs like lady bugs as well as bad bugs, so be cautious.
Aphids are not a big problem to me, but many gardener friends complain about them. To avoid attracting them, avoid overfeeding plants. Excessive nitrogen causes lots of tender growth, which is especially attractive to aphids. Sweet alyssum is a beautiful little flower that lures in tiny, nonstinging parasitic wasps that help control the aphids naturally; companion planting alyssum with your aphid-prone plants helps to control them.
If you are an early planter and are harassed by leaf miners in your beets, simply wait until after the lilacs bloom to plant your beet seeds. The species of leaf miner that attacks beets is no longer active at that time. Row covers work well in keeping this pest away from spinach, chard and other susceptible crops, and since these do not need pollination, keeping all insects out is not an issue.
If you have problems with slugs (and who doesn't at times), yes, it's true, slugs are attracted to beer, and yes, they will fall into a shallow, beer-filled container and drown. I cannot confirm that they get drunk before ending up in the pool, but either way the result is the same. Jessica Walliser says, “If you've ever emptied a saucer of putrid beer filled with slug carcasses, you truly know what gross is,“ and she suggests a better, less disgusting way to deter slugs is to surround susceptible plants with a ring of copper wire or copper tape placed on the soil. Slug slime reacts to contact with copper, giving the mollusks a mild shock and causing them to leave the area. I have not tried that yet.
Other things I have tried are to avoid using straw mulch around any plant that is highly attractive to slugs. Slugs love straw, but seem less attracted to wood chips or dried grass clippings. Also, don't water slug-prone plants in the evening. Water in the morning so the plant and soil dry out during the day and are less slug-friendly by nightfall when they come out to party.
I hate imported cabbage worms and cabbage loopers. These pesky worms develop from eggs laid by a white moth and will decimate any brassica crop. They are especially fond of the tender parts at the center of broccoli, cauliflower and cabbage. When they're done, the plant may survive, but it will not produce a head. The only effective control I've found is to use floating row covers (or in my case: netted fence boxes) to protect the plants from sprout to harvest. You also may want to mount some bird houses in the garden. Chickadees and wrens consume thousands of caterpillars while raising their young. Enlist all the help you can!