Growing Fruit & Nuts
Few things in this life give as much satisfaction as picking a beautiful, juicy piece of fruit from your own orchard and there are few places on the planet which offer better growing conditions for fruit and nut trees than Southern Australia. Our cool, wet winter cleanses the soil of built-up salts in the root zone and sets the tree's biological clock so that flowering and pollination occurs effectively. Then our hot, dry summer with cool nights builds that perfect balance of flavour, sugar and acid in the fruit and discourages diseases and pests.
Whether you want to grow for self sufficiency or for commercial income, the same considerations apply in developing and maintaining an orchard.
Please use the links below to jump to specific information:
- Planning is paramount
- Foundations of a successful orchard - stock, layout and irrigation
- Planting mistakes last forever
- Managing your trees
- Some species for the Adelaide Hills
- Good sites
- Excellent sources of unusual fruit and nut trees in Southern Australia include:
Planning is paramount
Analyse what you really want from your orchard... you may decide that fruit growing is so important to you that you need to get another piece of land which has the soil and water required for growing the quantity and varieties of fruit and nuts you've set your heart on. If you plan a commercial or semi commercial enterprise you are crazy if you don't first test for soil fertility, water quality and quantity and the physical soil characteristics as you go deeper, layer by layer into the ground; many a good tree fizzles out because it is planted over a limestone or impermeable clay layer. Getting Bureau of Meteorology rainfall and temperature data and testing for soil pH is basic information even for backyard growers.
With a knowledge of the capabilities of your land you can sensibly start looking at species and varieties which will grow happily on your property.
Collecting facts about the amazing, mouth-watering plants you can grow is one of the most pleasant parts of planning an orchard and many a dark and stormy night or lazy Sunday curled up by the fire can be spent reading the brilliant books available on growing fruit. Two books I would buy rather than borrow from the library are 'Growing Fruit in Australia' and 'The Complete Book of Fruit Growing in Australia'; they are references you'll use constantly. Paul Baxter is factual and brief whilst Louis Glowinsky, a doctor from Melbourne, is a consumate story teller, bringing alive the amazing backgrounds of every species and detailing management practices old and new.
The Primary Industries SA Information Centre at Murray Bridge is a gold mine of information and has an excellent mail order catalogue and membership of the Western Australian Nut and Tree Crop Association provides regular newsletters and booklists, a wonderful yearbook of in-depth articles about rarer species and a powerful network of tree crop enthusiasts. The Australian Nutgrower is 'the' industry journal. The Internet also boasts more material on horticulture every day. Educational courses provide information and an opportunity to discuss your ideas.
Foundations of a successful orchard - stock, layout and irrigation
Careful placement of trees with relationship to each other and a recorded planting plan pay rich rewards
The layout of an orchard depends on the type of tree being grown (walnuts may be spaced at 7 metre intervals in the row and 9 metres between rows while raspberries are planted at half metre spacings in the row and grown on trellises 3 metres apart). The size of the mature tree or bush is thus critical information if you are to plan for interrow spacings down which equipment can travel. But even trees of the same variety may not grow to the same order of size because of the effect of rootstocks, the 'root part of the tree' onto which the productive top part (scion) has been grafted. Some rootstocks make the tree more vigorous and disease tolerant, some dwarf the tree making picking, bird protection and pruning easy but also make it more demanding of care and attention, possibly even trellising. If you've got limited space or are aiming for a high input orchard the dwarfing rootstocks may be attractive but if you have lots of space and would like to keep inputs to a minimum a tree grown on a vigorous disease and pest tolerant stock would be best. Growers should not underestimate the damage something like Wooly Aphid can do to apples on non resistant stocks. Trees need to be ordered on the appropriate rootstocks and we are lucky to have wholesale nurseries around the Hills specialising in various species and able to supply specified rootstock/scion combinations. If you've got green fingers or are too impoverished to buy grafted trees you can grow the rootstocks and graft them yourself - it is very satisfying work.
Bear in mind the importance of pollination for most trees and follow the recommendations for the placement of pollenizing trees or rows of trees. Try also to get diversity into the orchard and its surrounding windbreaks...it is nice to have hundreds of predatory species zooming in from plantings of Melaleucas to hammer away at your pests! Windbreaks must be part of the plan and we have standardised on non-suckering Casuarinas as wind-firm, nitrogen- fixing 'wonderbreaks'; but even they can compete with your crop trees and should be planted at least 12 metres from the orchard.
Orchards are best established on gently sloping or well-drained flat ground and tree lines should be aligned North South. Picking, machinery access, vehicle safety and erosion become challenges on steeper country. On gradients between 1:30 and 1:17 contour planting should be considered; anything steeper than that should really be reserved for forestry unless the intensive management of terraces is accepted into the plan.
Summers can get very hot around Adealide and a heat wave at the wrong moment can vitually ruin a crop unless supplementary water can be provided. Irrigation also enables young trees to be established easily and quickly so any new orchard should be equipped with at least some sort of watering system. The arguments rage between the 'drip' enthusiasts and the under-tree sprinkler lovers. For those with somewhat salty water (over 1000 parts per million) and those with very limited flows of water, drippers offer real advantages. For organic growers, (who are not interested in using herbicides down tree rows, the permanent under-tree sprinklers are a curse as they constantly fall prey to mowers and have their spray patterns destroyed by weeds; but for herbiciders with an adequate supply of good quality water, under-tree micro sprinklers work well. Most irrigation supply companies will help you design an effective system for a small orchard for free and provide all the parts as an easy-to-use kit. If you liked Lego as a kid you'll love putting an irrigation system together. One component that may not immediately come to mind but is worth designing into moderate sized orchards is a Venturi-type system for sucking liquid fertilizer (organic or conventional) into the irrigation line. Called 'fertigation' the technique enables you to easily correct trace element deficiencies or boost plant growth at critical times. It can be tempting to leave irrigation mains and sub-mains on the surface but it is just a matter of time before they will be damaged, so put them at least 40cm underground (deeper if you think you may ever use a ripper).
Planting mistakes last forever
Planting trees which are poor specimens (eg old plants 'out on special', trees which are rootbound, or trees where the graft between rootstock and scion looks nobbly and unhealthy) is a waste of time and space so pay for good stock and be rewarded with rapid growth. You may have to order them six months or more in advance. Don't plant into unprepared ground... it should have been deep ripped some months in advance of planting, weeds controlled and a good slug of well composted manure incorporated into the soil before the irrigation system or trees go in. In America, growers commonly use excavators to mix the various soil layers and fertilizers in the planting hole to a depth of 1.5 metres. If the top soil is thin or the gound is poorly drained construct a mound to plant onto. Never plant the tree so that water pools immediately around the stem or you'll end up with collar rot and if the roots are knotted either spread them out in the hole or chop off the knotted bits. Follow the 'pruning at planting' instructions from the supplier of your trees. If planting in summer irrigate before planting.
Managing your trees
The wise old American pecan growers used to say 'The best fertilizer for an orchard is the footsteps of the manager', but whilst observation and timely management action are the keys to success, the odd drop of fertilizer does help a lot. We use composted animal manure to replace the bulk of the nutrients lost when fruit and nuts leave the property and for Nitrogen fixation from the atmosphere we use leguminous inter-row plantings like sub clover. This inevitably leaves the odd deficiency, which is picked up by soil or leaf testing and can be corrected by small additions of other fertilizers such as wood ash, minerals, rock phosphate etc. Non-organic growers have a huge arsenal of artificial fertilizers at their disposal.
Weed control is the main management challenge in horticulture and whilst herbiciding and mowing are the usual techniques employed, the use of grazing animals, particularly geese, but also other soft-footed, low maintenance creatures like wallabies and alpacas, can minimise energy intensive inputs. Foragers such as chickens are invaluable in controlling insect pests and can eliminate the need for insecticidal spraying. The addition of animals provides a more diverse income but requires good boundary fencing and some internal fences; cheap, portable electric fencing can be used to good effect within the property.
Pruning has largely been mechanised in grapevines and can be in tree crops to a certain extent, so if you dislike pruning, it may be best to go for species that don't need detailed pruning (nuts, olives etc) or where mechanisation is feasible. On the other hand, if you would enjoy the challenge of shaping and guiding a strong, healthy tree which produces well sized, high quality stone fruit every year then pruning is good fun. There are some excellent books on pruning, particulaly 'Pruning and Training of Fruit trees' by Warren Somerville, but we use a very simple system for almost all our trees which is called Central Leader training and aims to convince the tree to have one main trunk from which the branches emanate fairly horizontally, following a spiral track up the tree, like a barbers pole. The system gives a compact tree with strong branch attachments and minimal pruning once the shape has been established.
Pest and disease control are substantially minimised by building diversity into your plantings and using foraging animals but things like Curly-Leaf and birds will take their toll on some crops unless timely action is taken. We chose to put in major plantings of Pistachios, Pecans, Olives and Sweet Carobs which are not much troubled by birds or leaf diseases and put up with netting grapes and spraying stone fruit with a copper-based fungicide. Others also use bird scarers and a range of synthetic fungicides. Biodynamic farmers use 501, a silica-based spray used to limit fungal infection. Bear in mind the rule of thumb for biodiversity plantings near your orchard - 'The bigger the tree the bigger the birds in it' ie shrubs will house less starlings and cockys.
Environmentally sustainable horticulture is growing fast in Europe as the demand for clean food explodes but even there it is not a field for those interested primarily in making money; it is hard work and has its ups and downs. In SA the challenge of making Adelaide a world recognised region for the production of premium olive oil (and replacing Australia's $100M bill for olive product imports), the joy of getting the first harvest of a new organically certified Australian fruit or nut variety into enviromentally responsible tummies and the satisfaction of starting up a completely new tree crop industry are backed up by reasonable prices for good quality produce of all sorts. Good markets also exist for value-added fruit and nuts, particularly if organically certified. We dry or make jam from our second grade fruit; its often got more flavour than first grade. Pickling your own olives is deliciously symbolic of the age-old desire to cut depedency on multinational food companies.
Commercial properties need to mechanise (and capitalise) to be profitable but low input self sufficiency orchards can be remarkably cheap to establish and run (eg irrigation system per tree 50cents, water per tree per year $1, long life knitted bird net per large tree $9, chook manure $25 per tonne).
Some species for the Adelaide Hills
- Olives - keep them on North facing slopes - Mission is a great dual purpose variety and Corregiola will give you brilliant oil. Olives have shown a capacity to wander off over the landscape and some enlightened councils warn that if your olives are not harvested in a timely fashion the orchard will be dug up with an excavator at your expense; sounds fair enough to me.
- Apples - they have to be good as there's plenty of competition - Niches for early, late and organic need consideration.
- Cherries - for those who love to have total control - bird exclosures, dwarfing rootstocks and trellising are in order.
- Figs - White Adriatic is an early one, good for jam, glace and fresh eating.
- Grapes - For wine be quick.
- Sweet Carob - north slopes, wonderful fire barriers - the beans are now saleable as SA has a processing plant.
- Walnuts - good new Uni of California varieties - watch the organic in-shell market go.
- Mulberries - the ultimate easy-care species with the world's most intensely flavoured fruit.