ORCHARD CULTIVATION
PLANNING YOUR ORCHARD
Position
Orchards grow best on gentle slopes or well-drained level ground, preferably facing north. At such sites tree rows should be aligned north-south, but on gradients between 1:30 and 1:17 rows should be laid out along contour lines – that is, against the slope of the hill, no matter which way the slope is facing. This layout captures water rather than letting it run off. It also makes picking and machinery access easier, helps with vehicle safety and combats erosion. Fruit trees should not be planted in areas shaded by houses, buildings, or other trees. They also should not be planted near fences or hedges, as these keep cold air trapped around young trees.
Soil Analysis
First test your soil for pH, fertility and tilth as you dig deeper into the ground. Ph test kits are available at most nurseries and hardware stores. Trees will not grow well if planted over a layer of stone or impermeable clay. Clay can be broken up with gypsum. Here’s how to find out if gypsum will work on your clay soil.
http://www.abc.net.au/gardening/stories/s1676965.htm
Fertiliser
Soil fertility tests can be expensive for the home gardener but this website shows how to perform many useful soil tests for free.
http://envirorealestate.org.au/soilcheck.asp
For commercial orchardists, a scientific soil test is essential. Without it, money may be wasted on unnecessary fertiliser applications, or trees may suffer from nutrient deficiencies.
For home gardeners it may be enough simply to add compost to the soil in conjunction with organic seaweed or fish fertiliser. Organically certified fertilisers can safely be used in any gardening situation if diluted according to instructions. Australian soils vary a great deal from place to place, but generally they are deficient in trace elements, which is why seaweed solutions can be very helpful.
To find out more about your area's climate and soils you could ask a local organic gardening organisation. There are some links here,
http://www.greenharvest.com.au/links/links.html
Soil Preparation
Several months before you plant the trees, deeply rip the soil. Get rid of the weeds and dig in a generous quantity of well-composted manure incorporated into the soil before the irrigation system is laid out or the trees planted.
Water
The Bureau of Meteorology provides free online rainfall and temperature data for your area. In most parts of Australia, you will need to provide irrigation when establishing young trees, and during the hot summer months.
Ideally, all orchards should be equipped with a watering system. Drip systems offer many advantages, including the most efficient use of water. Most irrigation supply companies will freely help you design an system for a small orchard and provide all the parts as an easy-to-use kit. You might wish to include a ‘fertigation’ system for sucking liquid fertilizer into the irrigation line. Bury irrigation mains and sub-mains at least 40cm underground to protect them from damage.
Water quality is, of course, vital. The purest is rainwater, but moderately salty bore water can be used successfully on many fruiting crops. When you are informed about your soil and water, you can choose fruit and nut varieties which will grow well on your land.
Windbreaks
Windbreaks are essential on rural properties.
The ideal windbreak is composed of several rows of trees planted at spacings that will reduce windspeed, without the turbulence that would be caused by an impenetrable screen. The more rows of trees, the more efficient the windbreak, but where space is limited, plant a single row using tree species that produce branches all the way down to ground level.
Distances between trees vary according to species used, but in multiple row windbreaks will generally be within the following range:
• Tall trees: 5-8 metre spacing, 3-6m between rows
•
Medium trees: 3-5m spacing, 3-5m between rows
•
Shrubs: 2-4m spacing, 2-4m between rows
The area sheltered by a windbreak is relative to the mature height of the trees. A windbreak will reduce windspeed by more than 70% and shelter an area roughly 20 times the mature height of the trees planted. Unless the length of the
windbreak is 15 to 20 times the height of the trees, the wind will be deflected around the ends and lose effectiveness.
You can plant windbreaks which have multiple uses, such as rows of Melaleucas to attract beneficial, predatory insects, or rows of Casuarinas as nitrogen fixers. Jackie French in her excellent article ‘The Magic Grove’ suggests starting a grove with some fruiting trees that may double as excellent windbreaks - ‘a very hardy tree that will survive severe frost, hellish winds, summers over 45C and drought... bunya, loquat, macadamia, or plum, pears or apples NOT on dwarfing rootstock - you need the big vigorous ones for this. If the seasons are good you can get away with trees like lillypillies, calamondins or oranges or any other trees that grow well for you.
‘In very windy areas plant a line of tall, very deep-rooted trees like walnuts or pecans to help protect the others. (Assuming you have deep soil so they CAN be deep rooted). But these are very large trees, and not suitable for a small garden except where you DON'T have wind and can prune off the lower branches to let in more light to other plantings.’
http://www.jackiefrench.com/groves.html
Windbreak trees should not be allowed to compete with your crop trees and should be planted at least 12 metres from the orchard.
Layout
The Hexagonal System or equilateral triangle system, (see diagram below, centre) is popular as the most economical system for planting orchards. In this system each tree is equidistant from the nearest neighbor in any direction. The land is equally distributed among the trees, and it is nearly all used without crowding the trees. It also has the advantage of increasing the number of trees about 15 per cent over the rectangular system without reducing the distance between trees.
Distances Between Trees
There is debate as to what is the proper distance between fruit trees. It is impossible to give any hard and fast rule, as it will differ with climate and soil conditions, and the characteristic growth of the variety.
There is always a tendency to plant trees too close.
This is undoubtedly due to the fact that there is a desire to use as much of the land from the beginning as possible, and because newly set trees always have the appearance of being farther apart than necessary.
Experience has proved that serious losses in the amount of fruit produced accompany close planting. Not only is the crop reduced, but orchard operations such as cultivation and spraying are interfered with in closely planted orchards.
Most growers hold that apple trees should not be set closer than twenty-five feet in commercial orchards, and that in most instances, thirty to thirty-five feet would be preferable.
Pollination is important for most fruit trees. The supplier of your trees should provide recommendations for the positioning of trees for best pollinisation.
The layout of an orchard also depends on the type of tree being grown and how big it will grow. Here are some examples of planting distances.
Recommended Planting Distances for Apple Trees Grown on Size-Controlling Rootstocks
|
Distance Between Trees (feet) |
Rootstock |
Nonspur Varieties |
Spur Varieties(a) |
Very Vigorous Varieties(b) |
Seedling |
18 - 25 |
12 - 16 |
25 - 35 |
MM.111 |
14 - 18 |
9 - 12 |
20 - 25 |
MM.106 |
12 - 16 |
8 - 11 |
17 - 22 |
M.7a |
10 - 14 |
7 - 9 |
14 - 20 |
M.26 |
8 - 12 |
5 - 8 |
11 - 17 |
Mark |
6 - 8 |
4 - 5 |
8 - 11 |
M.9 |
4 - 8 |
3 - 5 |
6 - 11 |
(a) For spur-type varieties such as Redchief Red Delicious, Lawspur Rome, and Oregon Spur.
(b) For very vigorous varieties such as Rome Beauty, Granny Smith, and Jonagold.
Spacing Requirements for Other Tree Fruits
Fruit Crop |
Minimum Spacing Between Trees (feet) |
Asian Pears |
20 |
Chestnuts |
40 |
Figs |
10 |
Pears |
20 |
Pecans |
70 (a) |
Persimmons |
15 |
(a) At maturity, approximately 20 years.
Source: North Carolina State University.
PLANTING YOUR ORCHARD
Buy Healthy Trees
Choose trees which are not rootbound, and which have healthy-looking graft joins.
Dig the hole.
Plant into your prepared ground (see above). With thin topsoil or in poorly drained, heavy clay soil build up a mound or ‘berm’ to plant each tree on, to avoid water logging, which can lead to crown rot.
For the same reason, do not plant the tree in a ‘well’ so that water pools around the stem. Measure the depth and width of the soil in your tree’s container. Dig a hole to that depth and two to three times wider. Pile the excavated soil to the side to be used later. Loosen the soil around the sides of the hole to help roots penetrate into the native soil. Don’t loosen the soil at the bottom of the hole because the disturbed soil may settle and leave the tree planted too deeply.
Plant the tree.
Slip the tree out of its pot or remove the burlap and ties. Prune off only those roots that tightly circle the trunk or are broken. With your hand, loosen and gently spread roots that circle the root ball. Set your tree in the hole, and lay a shovel handle across hole to check the planting depth. The top of the root ball should just touch the shovel handle. Add or remove soil until the top of the root ball is at the appropriate level.
If when you take the tree from its pot you find that the roots are knotted, untangle them and spread them out or chop off the knotted lumps. Follow the 'pruning and planting' instructions from your nursery. If you plant in hot weather, pour water into the hole before planting. If planting a bare-root tree, shape a small mound of soil in the center of the planting hole, and adjust the tree height until the base of the plant is at the correct level. Spread the roots over the mound of soil without bending or breaking them.
Fill the hole and water the tree.
If you’re planting in very poor soil, improve the dug-out soil with one third part compost before backfilling. Fill the hole half full with the excavated soil. Water thoroughly and allow to drain. Fill with the remaining soil and rake it gently into a low mound over the planting hole. Pull the soil away from the trunk to form a doughnut-shaped ring around the outside of the planting hole. Water again, gently.
Make sure the tree's trunk meets the ground at exactly the same level as before. Wet soil piled against a trunk can cause rot.
Staking
Where local winds are strong, stakes will help hold the until the roots have established. If you stake the tree use at least two stakes and tie it fairly loosely so the trees roots will grow strong not become dependent on the supports.
Read this article about planting fruit trees: http://www.abc.net.au/gardening/stories/s1178536.htm
Tree Maintenance
Regular deep watering is essential until the trees root systems are established into the surrounding soil.
MANAGING YOUR ORCHARD
Keep the Weeds Down
It is important that the tree’s growth is not impeded by competition for water and nutrients by weeds growing along the rows, especially around the trunks, where vegetation can harbour fungus that causes collar rot. While herbicides and mowing are the most common weeding techniques, grazing animals, particularly geese, but also other soft-footed creatures like wallabies and alpacas, are an excellent energy saving, organic alternative. Foragers such as chickens are invaluable in controlling insect pests and can eliminate the need for insecticidal spraying. They also provide fertiliser.
Use Plenty of Mulch
Mulching promotes growth, increases soil moisture holding capacity, benefits soil structure and helps increase soil nutrient availability, organic matter levels and soil microbiology.
Use composted animal manure to replace the bulk of the nutrients lost when fruit and nuts leave the property. For nitrogen fixation from the atmosphere, plant leguminous inter-row plantings like sub clover. This inevitably leaves some deficiencies, which can be 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.
Fertiliser
If planting during winter, don't add fertiliser until the weather warms up, as the plant is dormant and can't use the nutrients. In acid soils calcium deficiency can be a problem so, after winter pruning, apply two handfuls of dolomite lime around the base of the tree. Now and then, apply liquid fish fertiliser, especially when trees are putting on bursts of growth and while fruiting. Potash is useful too.
Stone Fruit: Feed annually after flowering finishes using a complete organic fertiliser, then monthly using either seaweed or a flower and fruit fertiliser.
Citrus Fruit: Keep citrus trees happy and healthy by using organic based fertilisers. Add about a handful of fertiliser per square metre once a season and cover with mulch.
Apples & Pears: In early spring, heap a circle of rotted manure around the drip zone of the tree. Add a couple of handfuls of blood and bone at that time, and again in late summer. A couple of applications of trace elements in early spring, late summer and again in mid-autumn will keep your tree growing well.
There’s a great article on organic fertilisers here: http://www.abc.net.au/gardening/stories/s984417.htm
Pruning
There are some excellent books on pruning, particularly 'Pruning and Training of Fruit trees' by Warren Somerville.
Peter Cundall gives good advice on pruning fruit trees: http://www.abc.net.au/gardening/stories/s1580442.htm
Most importantly, after pruning one tree and before pruning the next, sterilize your secateurs to decrease the risk of passing on any viruses or bacteria. The best sterilizing agent is methylated soirits, but dilute bleach or tea tree oil can also be used.
Pest and Disease Control
With diverse plantings of trees and flowers that attract birds and beneficial insects, and allowing soft footed animals and fowls to forage in your orchard, you can minimise pest problems. Nonetheless diseases such as curly-leaf can occur. Spray stone fruit with a copper-based fungicide such as Burgundy mixture. Biodynamic farmers use 501, a silica-based spray used to limit fungal infection.
Throw fine, powdery wood-ash all over the leaves of pear and cherry to get rid of pear and cherry slug. Fruit-robbing birds can be kept out with TIGHTLY STRETCHED netting (loose netting can be fatal for our native species) or bird scaring devices.
Trees such as Pistachios, Pecans, Olives and Sweet Carobs are not much troubled by leaf diseases or by birds robbing the harvest.
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