The best defence for your garden is a strong offence: identifying your problem precisely, keeping your garden tidy, maintaining your plants, selecting disease-resistant varieties, rotating crops and using nature – not chemicals – to combat unwanted intruders.
Know your enemy
You can only effectively fight something if you identify precisely what you are up against. If the leaves of your tomato plants turn yellow, it might not be a disease; it could simply be nutrient deficiency. If rabbits eat your lettuce, a fence makes sense, but rabbits tunnel so you must bury some of the fence into the ground.
Keeping your garden clean
Rabbits and other wildlife are always on the lookout for food, water and shelter, therefore sanitation in your garden is important. Raking up fallen leaves, cleaning up rotten fruit that has fallen on the ground and moving it to the compost will discourage unwanted visitors. After the season is over, remove all spent plants. From your small fruit bushes cut out dead or diseased branches and limbs.
The healthier a plant, the less likely it will be affected by a disease. Providing sufficient water, light, sun, air, regular weeding and nutrients are essential to plant health. Maintain planting distances as specified on the seed packet. Planting too densely allows moisture to get trapped, and becomes a breeding ground for fungi and other diseases.
Select disease-resistant plants
Select plants and seeds that are resistant to common pests. These are not genetically modified plants, but rather natural varieties that have been bred for stronger resistance.
Crop rotation helps to prevent disease. Some plant diseases remain in the soil and can affect plants from the same crop family the next year, since they are susceptible to similar pathogens. As well, different crop families take different nutrients out of the soil. If you plant your garden in containers, use fresh soil every year. The old soil has been depleted of nutrients because of the intensive root system in a container.
Many insects are important for the health of your garden. Especially pollinators (e.g. bees) and insects that kill unwanted insects, such as ladybugs, are crucial to your garden. You can attract them by planting certain herbs and flowers, such as borage, parsley, coriander, dill, sunflowers, coneflowers and daisies.
Read the label
There is no single, cure-all remedy against insects so you must first determine precisely which insect is affecting your plant. Check the label to see if it targets your enemy. If you think you absolutely must spray a pesticide, use organic pesticides and make sure it is suitable for crops, and at what stage of growth or harvest it may be used. Using chemicals against insects is not only hazardous to your health but can also kill beneficial insects.
Planting certain plants next to each other can help repel unwanted insects, or attract beneficial insects. Often strongly scented plants, such as herbs or flowers, confuse and distract some insects from the vegetables. For specific companion plants see articles on individual crops.