It’s true to say that you will never completely eradicate pests and diseases from your vegetable plot and a certain level of attack can be tolerated especially if the edible part of a plant is not affected. But there are a few measures you can take to limit the damage they can cause. The key to keeping insect pests and diseases away from your vegetables is to make sure you grow strong healthy plants that have access to sufficient water and nutrients. Weedy plants are much more susceptible to diseases. However, if you do find you need to take more drastic measures then there is no real need to use pesticides, there are a number of organic methods you can try.
Slugs and snails
These two are probably one of the biggest problems for any gardener, but especially the vegetable gardener. They can consume a whole batch of young vegetable plants over night. Slug pellets are an obvious method of attack for dealing with slugs and snails, but they are not organic and can be harmful to other wildlife. Aluminium sulphate powder is a good alternative. Unreliable methods such as beer traps and coffee grains can be made more effective when combined with human intervention – nothing really beats an hour or so in the evening walking round your patch removing slugs and snails as they emerge to feed. You can also reduce their numbers by removing any obstacles they may use to hide in or under during the day.
You can give your vegetable garden a head start against insect pests by choosing varieties that are resistant to attacks, such as fly-resistant carrots. You can also try and prevent insects from attacking by providing protection in the form of mesh or barriers. Mesh or fleece is particularly effective against carrot fly and cabbage white butterfly, but make sure your mesh has the correct sized holes small enough to deter the pest you want to prevent. Other larger insect pests like caterpillars can be easily removed by hand.
A good alternative to pesticides for getting rid of really problem pests such as black fly on runner beans is a mixture of soap and water sprayed directly on to the plant. This method does not harm more helpful insects like bees. You can also try planting companion plants known to have some success in deterring insect pests. The strong fragrance of marigolds for instance is believed to protect vegetables from most insect pests.
As I mentioned earlier, growing healthy plants in the right conditions goes a long way to preventing disease. Again, it is a good idea to choose those varieties that have been bred with some resistance to disease, such as potatoes that have a high resistance to blight. Sulphur dust is effective against fungal diseases such as powdery mildew. Some diseases that affect vegetables are dependent upon the weather. Blight for example also affects tomatoes and occurs in warm wet weather during summer. This is a case where it is probably easier to accept defeat rather than try and treat. If you live in an area where this type of weather is common there are varieties you can buy that do have some resistance.
Other things you can do
There are a number of simple tasks you can do to make sure your vegetables remain healthy and have the optimum resistance to pest and disease attacks. Make sure you manage your plot well. Crop rotation helps reduce any threat from disease. Make sure you add plenty of organic matter and fertiliser to your plot each year to maintain the health and nutrient levels of the soil. Keep on top of weeds that will compete with your vegetables for water and nutrients. Make sure your vegetables have plenty of water, particularly in dry weather, and feed your vegetables regularly. This is especially important for vegetables grown in garden planters which will have more limited access to moisture and nutrients than those grown in the soil.