How to Grow Organic
A 10 minute read by Peter Worsp
There is nothing quite like the taste of fresh vegetables straight from the garden. Add to this the satisfaction and sense of achievement, the savings, the knowledge that your vegetables are free of nasty pesticides and you have some very powerful reasons for growing your own vegetables.
Many well established gardening practices such as composting, mulching and crop rotation are the basis of gardening natures way. Organic gardening is a technique that avoids the use of all synthetic fertilisers and pesticides. However, this article follows a more pragmatic but environmentally friendly approach.
At a Glance
- Warm sunny site
- Free draining soil
- Lots of compost
- Fertiliser - use animal manures such as pelletised sheep manure
- Plants - select strong disease resistant varieties
- Pesticides - use low toxicity environmentally friendly pesticides
Recently the boundaries between conventional and organic gardening have become blurred as conventional gardening adopts more of the sustainable principles of the organic way and organic gardeners recognise that some natural pesticides are more toxic than synthetic ones.
Hence today’s natural organic gardeners use all the proven, good garden practices of composting, mulching, crop rotation and use animal manures for extra nutrition. They also select plants and varieties more suited to the soil, climate and season to ensure best results.
The key to organic gardening success is a good soil. The main function of soils is to hold a reserve of nutrients and water for plants. A good soil is one that holds nutrients and water in a manner in which plant roots can extract them easily. To do this soil should be open, aerated and drain freely of surplus water. However at the same time it should hold ample water for plants.
To do all this the soil should be high in organic matter i.e. compost or similar material. Hence the basis of organic gardening is to have a soil with lots of compost. Compost needs to be added every year to maintain the soil in good condition.
Compost can be purchased in bags or you can make your own. Making your own not only provides an ongoing supply of compost but it also gets rid of most garden and kitchen waste. See the information sheet on 'Compost Making' for full details.
This is an old, well proven means of avoiding disease build up in the soil. It is used in the vegetable garden and the annual flower garden. If the same crop e.g. tomatoes is grown in the same soil every year the plant health and yield will decline to a point where it is no longer worthwhile. This is because soil fungus diseases specific to that crop, build up to a high level and suppress growth. This problem can be avoided by rotating crops around the garden, so that any one type of crop is only grown in any one area for one year in four.
The product groups are:
- Brassicas and leaf veges - cabbage, cauliflower, broccoli, brussel sprouts, swede, turnips, silver beet and lettuce
- Legumes - peas, beans, broad beans
- Root crops - potatoes, carrots, parsnips
- Miscellaneous – tomatoes, cucumber, zucchini, pumpkins, sweet corn
- Organic gardeners use predominantly animal manures, such as pelletised sheep manure to provide additional feeding for plants
- A high level of compost use and animal manure will lead to an increase in soil acidity. It is therefore advisable to apply an annual dressing of lime at about 300g per sq metre
Pest and Disease Control
The organic gardening practices outlined in this article will minimise pests and diseases. However there are still some problem pests and some plants that are commonly attacked.
The following products are recommended for organic growers. Generally they are less effective than conventional sprays and more frequent spraying is necessary.
- Pyrethrum - an old favourite made from a daisy, kills most insects quickly on contact. There are no toxic residues and food crops can be harvested 1 day after spraying. On the negative side Pyrethrum has no lasting effect, therefore repeat spraying is required
- Grosafe Enspray99 - a refined bio oil which controls many insects by smothering them and cutting off air supply. Oil is effective against small sucking insects especially aphids, mites, mealy bug and scale. Again repeat spraying is usually necessary to clean up bad infestations
- Insecticidal soaps such as Yates Natures Way and Tui Eco Pes are effective against small soft bodied insects but repeat spraying is required
- Yates Success Naturalyte - made from a natural bacteria extract is very effective against caterpillars and thrips
- Yates Mavrik is an environmentally friendly synthetic insecticide safe to bees and soft on ladybirds. Effective against sucking and chewing insects such as caterpillars, thrips, aphids, white fly, vegetable shield bug, passion vine hopper etc.
- Grosafe FreeFlo Copper - a good general purpose fungicide which prevents many diseases including blight on tomatoes and potatoes; downy mildew on roses; leaf curl on peaches and nectarines
- Yates Lime Sulphur Spray - a good winter clean up spray for deciduous fruit trees. It controls over-wintering insects and fungus diseases as well as lichen
- Yates Natures Way fungus spray contains sulphur and copper for broader control
- Yates Liquid Copper
- KiwiCare Organic Super Sulfur - which is not a defoliant as lime sulfur is so it's safe to use year around as needed
Pest and Disease-Resistant Plants
- An important tool for the organic gardener is to grow predominantly pest and disease resistant plants
- There are a range of plants in all categories of gardening that are relatively resistant to major pests and diseases. Organic gardeners should focus on these species and varieties. Ask our garden centre advisor for help.
Some examples of disease resistant varieties
- Apples - Initial, Boujade, Liberty, Prima, Priscilla, Sir Prize
- Grafted tomatoes, hybrid varieties
- Flower Carpet roses.