Stoep Harvest part 9: Pest control

This time on Stoep Harvest we look at pests.

Pests come in all shapes and sizes. Large pests may include dogs, cats, birds, porcupines, monkeys, baboons, and even children and their sports equipment! Smaller pests include insects such as caterpillars and beetles.

There are even microscopic pests such as nematodes and eelworm that cannot be seen by the naked eye but cause your carrots to twist and turn into some rather strange looking shapes.

And a pest may be very subjective – for an avid birdwatcher, a rare bird eating from the garden will be a joy and not a pain. For many commercial industrial farmers, all insects seem to be grouped as pests. These farmers use powerful chemicals that kill all insect life on the land, rather like bug genocide.

For organic growers such as myself, we see the benefit of a garden breaming with diverse life – including certain insects labelled as pests by others. Some organic extremists argue that there should always be enough food growing to share a portion with pests rather than interfere with the ecosystem. Sadly, in our smaller urban gardens there’s not usually that much to share!

A year-round preventative approach

An important concept to emphasise is that organic pest control is a preventative approach. Thus, even though I am writing this as an April activity, it should be carried out year round. It is especially important to consider when designing the garden, as will be made evident. Organic pesticides are less potent than synthetic pesticides and are therefore far less effective as treatments.

Larger pests are best managed with physical structures. Small wooden fences are the best solution for dogs and porcupines. Strong chicken wire or shadecloth enclosures are the only solution I’ve found to work with baboons. Birds do not like flashing light, so try hanging old CDs in branches or on string in the garden.

Moles need a category of their own. Garden centres abound with various solutions. From my experience, the allium (onion) family is the best natural deterrent. A scattering of tulbaghia, leeks, or spring onions helps keep them at bay. An extreme solution is to lay chicken mesh 40cm beneath the soil, creating a protected underground enclosure.

Right companions deter pests

Medium and small pests are best deterred with intelligent design and companion planting. The white cabbage moth, for example, cannot stand the smell of rosemary. An organic pest control method is to plant your cabbage, broccoli and cauliflower around rosemary bushes. Another common challenge is the aphid. These also do not like strong smelling flowers such as by nasturtium, marigold, scented geranium as well as various herbs.

A little known fact is that snails love the scent of beer. Submerge an old yoghourt container into the garden and half fill it with beer. Check each morning for snails that have had a late night party and cannot get old of the container. Snails also do not like rough crunchy surfaces such as egg shells, sea shells and oak leaves.

Organic pest control frequently looks to combat pests by encouraging natural predators. For example, a single ladybird will eat hundreds of aphids each week. A ladybird is therefore a great companion in the garden. If you find one elsewhere, carefully move it to the base of a vegetable plant so that it can climb up and eat any aphids. Attract ladybirds with colourful flowers close to the veg garden such as hyssop and sunflowers.

Natural predators work for you

Another example of a natural predator is the owl. Build an owl box (various designs are available online) and place high in a tree. An owl will hunt mice, rats and moles.

Having designed a beautiful and naturally pest repellent garden, you may still need to spray regularly. A general purpose organic pesticide is easy to make. Simply brew a ‘tea’ of chopped onion, garlic and chillies. Leave to flavour the water for a few days in a sealed container. Strain the mixture and add 50 parts water to 1 part liquid paraffin. Finally, make a lather in the mixture by grating sunlight bar soap. As you spray the leaves, the lather helps the mixture to stick.

Many other pest repelling recipes and companionships can be found in books and internet sources. I encourage you to practice different concoctions and planting layouts; keep a notebook of what works in your garden and share the organic approach with your friends and neighbours. I wish you every success.

April Planting Table (seeds)

• Western and Southern Cape: beetroot, broad bean, cabbage, carrot, leek, lettuce, onion, parsley, parsnip, pea, radish, swiss chard, turnip.
• Inland: broad bean, cabbage, carrot, lettuce, onion, parsley, pea, radish, swiss chard, turnip.
• Coastal KZN: bean (broad, bush and pole), beetroot, broccoli, cabbage, carrot, cucumber, eggplant, leek, lettuce, parsley, parsnip, pepper, potato, radish, squash, swiss chard, tomato, turnip.

By Sam Adams

Sam runs Living Green, an organic food gardening company in Cape Town.