No crops are immune to pests and diseases, and you will inevitably come across a few problems in the course of growing your own fruit and vegetables. Prevention is better than cure, and many setbacks can be avoided by good garden management and giving your plants the best care and attention.
Although almost any crop you grow will be under threat from some type of pest or disease, certain groups of crops, such as brassicas, are especially prone to specific diseases, like clubroot. Fortunately, there are alternatives to simply reaching for a bottle of pesticide: basic plant care is the place to start. Regular feeding and watering will encourage plants to become as strong and naturally robust as possible. You can also start them off under cover to give them an advantage or grow resistant varieties. Weeds can provide breeding grounds for pests and diseases as well as competition for crops, so remove them on sight. In some cases, appropriate chemical controls may be the best option; ensure that you use them safely.
This technique provides optimal growing conditions for your plants. The basic premise is to avoid planting the same groups of vegetables in the same place more than once every four years. This discourages the build-up of diseases that affect specific plant groups and also allows plants to benefit from the nutrients left behind in the soil by its previous occupants. Think of your crops as belonging to three distinct groups for rotation:
- potatoes and tomatoes
- brassicas, such as cabbages and broccoli
- legumes, such as peas and beans, with onions and roots, such as carrots and parsnips
Keeping this in mind, your beds would mimic the following over the course of a three-year plan for growing crops:
- Year one: Potato family and tomatoes
- Year two: Legumes — peas, broad beans, green beans, runner beans — and also onions, carrots, beets, parsnips and celeriac
- Year three: Brassicas — Brussels sprouts, cabbage, cauliflower, kale — radishes and turnips
- Year one: Legumes — peas, broad beans, green beans, runner beans — and also onions, carrots, beets, parsnips, and celeriac
- Year two: Brassicas — Brussels sprouts, cabbage, cauliflower, kale — radishes and turnips
- Year three: Potato family and tomatoes
- Year one: Brassicas — Brussels sprouts, cabbage, cauliflower, kale — radishes and turnips
- Year two: Potato family and tomatoes
- Year three: Legumes — peas, broad beans, green beans, runner beans — and also onions, carrots, beets, parsnips and celeriac
Good gardening practice is key to producing healthy plants and a high
yield of good-quality produce. Plant out healthy seedlings, plants, or
trees into well-prepared, disease-free soil, and tend them using clean,
disinfected tools. It is important to keep the growing area clear of dead or decaying plants — remove any diseased plant material as soon as
you see it, and destroy it; do not place it on the compost heap since
you will risk further infection. Keep plants well fed and watered so
that they are better able to fight diseases.
Barriers and Traps
Attacks from various pests can be prevented if you protect fruit and
vegetables. Covering plants in tents of fine, insect-proof netting or
horticultural fabric will provide a barrier against pests, such as
carrot fly, cabbage root fly, flea beetle, aphids, butterflies and
birds. Copper tape or grease around pots will deter slugs and snails,
and grease bands wrapped around tree trunks will stop female wingless
moths from climbing up to lay their eggs. Traps, such as sticky wasp
traps, can be used to catch and kill specific pests.
Your chance of success with certain crops is greatly increased if you
grow resistant varieties, bred to withstand specific problematic pests,
for example, carrots bred to resist carrot fly. Another option is to
choose varieties that have been awarded the All America Selections
Award. AAS crops have good general resistance to pests and diseases, are
reliable, not prone to reversion, do not require special care, and are
widely available. The list is regularly reviewed and updated as new
varieties become available.
Choosing to grow fruit and vegetables organically is a personal choice, but some gardeners find that it improves the health and vigor of their plants. They also feel better eating unsprayed crops and knowing exactly what has gone into producing them. Your plant health need not suffer if you refuse to use chemicals: allow nature to assist by reducing pests and diseases with the help of natural predators and biological controls. Using natural fertilizers, such as compost and manure, is also a part of this philosophy.
The key to achieving a healthy succession of fruit and vegetables is careful planning. The aim is to produce enough food to consistently supply you throughout the seasons without being overwhelmed by excess or having nothing on hand. Consider these two techniques in order to make the most of your garden:
- Intercropping: This technique maximizes your space and yield by allowing you to grow more than one crop simultaneously, using small crops in the gaps between larger crops. Plants such as sweet corn are ideal: with tall stems that cast little shade, they can be underplanted with lettuce, radishes or onions, or grown — in the traditional South American way—as part of the "Three Sisters," with squashes beneath and beans climbing the stems. You can also intercrop with ornamentals that attract pollinators, like the poached-egg plant, or those that divert pests, such as nasturtiums.
- Catch cropping: This technique is similar to intercropping but specifically involves sowing fast-maturing crops — usually those that take about 30 days or so to mature from seed, such as radishes or salad leaves — among slower-growing ones, such as parsnips or rutabagas. This allows the quick-growing crops to take advantage of ground that will not be required until the long-term plants are further developed. Sow this seed successionally in small batches every few weeks. This will provide you with a manageable supply and will ensure that you do not end up with excess crops.