People choose to go organic for a variety of reasons. For many it’s about going back to basics, while others want to help “green” the environment. Another common reason for choosing organic produce is the mounting evidence of the detrimental health effects of agricultural chemicals on humans and animals. Currently there are more than 270 different pesticides registered for use on fruit and vegetable crops in Australia.
Agricultural chemicals also kill many birds, beneficial insects, fish and frogs each year. Though foods sold in Australia and New Zealand are supposed to comply with the Food Standards Code, which defines maximum pesticide residue limits, a great deal of local and imported produce is not tested regularly, so consumers have no guarantee of the safety of locally produced or imported foods.
HEALTH CONCERNS
Many commonly used pesticides and fungicides are neurotoxins and some
have proven to be carcinogens or mutagens. Of particular concern are both the systemic pesticides and the herbicides applied to genetically modified (GM) food crops, because these chemicals remain in tissues throughout the plant and cannot be washed from our food.
Improved taste is another reason why consumers choose organic produce. Recent studies in Australia and overseas have confirmed that organic foods are significantly more nutrient dense than conventionally produced food.
There are sound reasons for this result. Organic produce is harvested when mature, and most flavours, vitamins, minerals and antioxidants become concentrated in produce close to maturity. Produce that is harvested early and artificially ripened is lower in nutrients and high in salicylates. Regular use of chemical fertilisers causes some nutrient minerals to become bound to soil particles and unavailable to plants.
Organic cultivation is sustainable
and environmentally responsible.
It focuses on restoring soil health through the regular replacement of humus (degraded organic material), protecting the soil surface and practising crop rotation, because organic farmers and gardeners know that pests and diseases are always caused by unhealthy soils.
HEALTHY SOIL
Healthy soil allows plants to obtain what they need for a strong immune system and to produce the pheromones that deter pests. Some of these pheromones are antioxidants that protect our bodies from damage in our chemical-saturated world.
Humus in soil provides a habitat and food for billions of beneficial micro-organisms. Bacteria and fungi produce substances that form stable soil aggregates, improving soil structure, drainage and moisture retention.
As a result, root growth improves and plants become more drought and heat tolerant. Some groups of beneficial fungi, combined with crop rotation, keep soil-borne diseases under control. Others provide a vast range of perennial families with moisture and nutrients in exchange for sugars produced by plant roots.
A group of beneficial soil bacteria assists legumes to fix nitrogen in their roots. Chemical fertilisers and pesticides deter the activity of soil organisms.
ORGANIC FERTILISERS
Organic fertilisers that form humus are made from what was previously discarded as waste. They contain all the mineral elements required by plants, animals and humans. Humus holds these nutrient ions in an easily absorbed form and regulates their release to plants so that some nutrients are not absorbed in toxic quantities. It also insulates plant roots against extremes of heat and cold and buffers them from an unsuitable pH in surrounding soil.
Organic gardeners and farmers keep digging and tilling to a minimum. Bare earth cultivation encourages erosion, destroys soil structure and results in water and carbon loss. It also leads to excessive weed growth as nature does its best to protect the soil surface with whatever seeds are in the soil bank. Between growing food crops, and in orchard areas, organic growers use stubble, cover crops, green manures or organic mulches to protect soil and replace nutrients and humus in topsoil as they decompose. Green manures and cover crops are produced by thickly sowing grain or legume seed over
a fertilised bed and allowing it to grow to knee height or flowering stage before slashing it and leaving it to decompose
on the soil surface.
Organic farming practices are just as suitable for home gardens, no matter what their size. Certified organic potting mixes are available for those who have to limit their gardening to container plants. Beetroot, baby carrots, cucumbers, salad greens, radishes, tomatoes and many culinary herbs can be grown in large pots on sunny balconies. Packaged organic fertilisers are available for gardeners who cannot recycle waste materials by composting or worm farming. Organic gardening practices are not only suitable for the vegetable patch. All plants benefit from organic cultivation.
It’s easy to convert from conventional chemical gardening to organic cultivation. As your soil’s health improves you’ll see
a steady decline in pests and disease while your entire garden becomes more water efficient and less stressed by extreme weather conditions. Organic cultivation provides our gardens with the best protection from climate change.
LOCAL ZONES
For gardening purposes, Australia can be divided into three basic zones: cool, temperate and warm. New Zealand has
a more constant climate that includes only cool and temperate zones.
Cool zones are those where frosts can continue into the spring, shortening the growing season. These zones are particularly good for shrubs and trees that require extended chilling during their dormant period. Many northern hemisphere plants grow well in cool zones.
Winter in temperate zones can be cold but soil warms quickly in spring. Despite the fact that summer can be very hot in some areas, with moderate irrigation a wide range of northern and southern hemisphere plants can be grown in temperate zones.
In warm zones, winters are mild and short and, in some areas, summers can be too hot and/or wet for conventional gardening. In Australia, warm zone areas from Rockhampton northwards are situated within the Tropic of Capricorn where winter temperatures can be warmer than summer temperatures in some cool zones. In this sub-zone a range of traditional vegetables and annuals can
be grown during the winter months.
Within these three basic zones, local microclimates will allow some gardeners to grow fruits, vegetables, shrubs and trees that belong to adjoining zones. Gardens on sloping ground where cold air can drain away and those protected from chilling winds are less likely to be affected by frost. If you are unsure of your gardening zone, consult your local horticulturist who will be able to advise you on suitable plants for your microclimate each season.
COOL ZONES
Suitable lettuce varieties, early and mid-season onion, spring onion, radish and English spinach can be grown now; also broad bean and peas in late May. Asparagus crowns, currants, kiwifruit, pistachio, raspberry and rhubarb crowns, deciduous trees, shrubs and vines can be planted in late May. In very cold areas, cover strawberries and frost-tender perennials with fluffed-up clean straw and prepare beds for potatoes and grapes.
TEMPERATE ZONES
Fast-maturing broccoli, open Chinese cabbage, winter lettuce, mizuna, early season onion, spring onion, radish, English spinach, tatsoi, garlic, annual lupin, pansy and viola can be grown in temperate zones. Prepare planting areas for potatoes with as much compost as you can spare.
In frost-free areas, broad bean, lettuce, peas, radicchio, radish, chamomile, garlic, rocket, yarrow, ageratum, aurora daisy, calendula, cornflower, dianthus, nigella, statice
and sweet pea can also be grown this month. Plant strawberry crowns, day lily and beardless iris bulbs. In frost-prone areas, sow broad bean, peas and sweet pea in late May.
WARM ZONES
There are plenty of options for warm zones. Cabbage, bulb fennel, leek,
lettuce, spring onion, peas, radish, English spinach, tatsoi, turnip, chamomile, coriander, rocket, yarrow, ageratum, aurora daisy, calendula, cornflower, dianthus, nigella, pansy, snapdragon, statice, verbena and viola can be grown in warm zones as can day lily and potted roses.
In warm zones from Rockhampton northwards, beetroot, carrot, pumpkin, rockmelon, summer squash, silverbeet, swede, sweet corn, tomato, watermelon, zucchini, dandelion, lemon balm, parsley, everlasting daisy, French marigold, nasturtium, petunia, phlox and sunflower can also be grown. Plant evergreen trees, shrubs and vines and sow lawns or lay turf to allow them to establish through the cooler months.
In warm zones south of Rockhampton, garlic, watercress, carnation, lilies, stock and sweet pea can also be grown. Anemone, ranunculus and suitable spring bulbs can be planted after several
weeks chilling in the vegetable crisper.
In warm zones, unchilled spring-flowering
bulbs will grow with very short stems.
Olive trees can also be planted and shasta daisy divided.
WHAT TO
DO IN MAY
May is a good month for tidying up perennial beds. Prepare planting areas for deciduous trees and shrubs and adjust soil pH if necessary. When preparing beds, add a moderate amount of fertiliser to the area, as fertiliser should not be added at planting time. Cover prepared areas with
a 7cm-layer of fluffed-up mulch to keep soil damp and prevent weed growth. Cut back dahlia plants and lift tubers if necessary. Grape vines should be pruned as soon as they are dormant, as late pruning of grapes can cause sap to bleed. Also, lightly prune tibouchina after flowering.
