By Jan Cashman 7/4/11
Growing your own vegetables is fun and rewarding, but there are a number of things that can go wrong with your vegetable plants. Some of these can be prevented from the beginning if you make sure you have a sunny garden spot with good soil and drainage, rotate your crops, and keep the weeds under control. Even with all this TLC, insects and diseases, deer and rodents, and hail and frost can still cause you problems in your vegetable garden. But, there are a number of safe, non-chemical ways to protect your plants from all these critters and acts of nature.
To keep deer and rabbits away, repellants work well, but need to be reapplied often. May 30, the day after we planted most of our garden, my husband Jerry noticed some of our broccoli and Brussels sprouts plants were pulled out of the ground and eaten. Before the day was over, we had a 5 foot fence made of woven hardware wire around the whole garden, including our raspberries, to keep the deer out. To keep rabbits out, gardeners are using finer fencing.
Right after we plant them, we protect our young tomato plants with Wall-O-Waters. These water-filled plastic contraptions warm up the ground inside them and provide a “greenhouse effect”, warming the plants during our cool spring days and nights, besides protecting from frost. Hot Kaps work the same way for small cucumber, broccoli, cabbage, and cauliflower plants.
Plastic & Net Covers
People gardening in raised beds often install hoops of PVC pipe above them, covered with clear poly that can be rolled on or off. When frost or hail is a possibility, they can easily cover and protect their plants. We have a raised bed planted in strawberries that the robins seem to love to eat as much as we do. We have covered the whole bed with a fine mesh to keep the birds out.
Row covers over plants susceptible to cabbage looper (the disgusting light green caterpillar that gets on broccoli, cabbage, cauliflower and Brussels sprouts) prevents the moth from laying the eggs that hatch into the caterpillar. This lightweight fabric is thin enough to let sunlight pass through it so can be left on the plants.
Companion Plants / Diatomaceous Earth
Marigold, garlic, and onion plants seem to repel aphids and other insects when planted close to other susceptible plants. Diatomaceous earth, an abrasive powder made from ground, fossilized sea algae, kills slugs and other crawling insects, like ants, cutworms and flea beetles. This organic product is easy to use–just sprinkle it on the ground.
Nutrient deficiencies can cause the leaves of your vegetable plants to turn yellow and shrivel or curl. Tomato plants are especially susceptible. Planting tomatoes too early in the spring before the ground warms prevents soil nutrients from being available to the plant. Warming the soil before you plant with red or black plastic, and planting your tomatoes in Wall-o-Waters can prevent this. Our customers often bring in tomatoes that have a black, indented, leathery lesion on the blossom end of their tomato for us to diagnose. This disease, called blossom end rot, is caused by temperature extremes, and fluctuations in watering which makes the calcium in the soil unavailable to the plant. Another cause is cultivating too close to the plant which disturbs the tiny roots that take up nutrients. To prevent blossom end rot, keep the soil under tomato plants evenly moist by careful watering and mulching. A red plastic mulch under your tomatoes is thought to make the plants grow faster, increase yield and will help hold water in the soil.
Fertilizer is important for a vegetable garden, but too much can be as bad as too little. Have your soil tested to find out for sure what it needs. Too much Nitrogen on tomato plants causes them to grow lots of leaves, but not so many tomatoes, but sweet corn needs more Nitrogen. Peas are Nitrogen fixers so don’t need any. Twice each summer we side-dress each row in our garden with a well-balanced (5-10-10), slow release (so it won’t burn the plants) fertilizer which has trace minerals (calcium, iron, manganese, and zinc). We use a fertilizer higher in Nitrogen for our sweet corn.
Destroy Infected Plants
Tomato plants are susceptible to many diseases and nutrient deficiencies, often with similar symptoms, which makes them difficult to diagnose. The Schutter diagnostic lab at Montana State will diagnose plant problems for you free of charge—just bring a sample to them. (For details, check out their web site, msuextension.org, and click on “diagnostics”.) If your tomato plants or other plants in your garden are diagnosed with a virus, destroy the infected plants before the disease spreads. Certain diseases, common to both tomatoes and potatoes, can be spread from one to the other.
Use these hints to help you have a successful vegetable garden this year.