Spacing of mango trees
Tree spacing will determine how many trees will be needed. Spacing will also affect yield, growth and the management practices of an orchard.
Block or high density plantings provide natural protection from wind, but avoid planting trees too close together because they will compete with each other for light, water and nutrients. Fruit is borne on the ends of branches, so spacing too closely may severely limit fruit production in mature trees due to shading.
At Carnarvon, space the rows 4.5m or 9m apart and the trees 5m apart within the rows. When trees in the 4.5m rows start to touch remove alternate rows and alternate trees (diagonally) within the row so that those remaining are 10m apart on a triangle.
If required, when trees are ready for thinning, alternate trees may be topworked or reworked to superior varieties. Planting high density hedge rows in Carnarvon has proved successful in attaining very high yields, however this system does require additional capital outlay to establish and manage.
In Gingin, cool weather severely restricts growth of the trees and lends itself to high density plantings. Row spacing of 6-8m and tree spacing of 2.5-3.5m should be considered.
In Kununurra, trees tend to be vigorous due to the warmer climate. This limits the potential for high density plantings with current technology. For lighter soils row spacing of 10m and tree spacings of 5m are recommended. On the heavy or clay soils vigour is reduced so row spacing of 8-9m and tree spacing of 4-5m may be used. Less vigorous varieties such as Irwin may be planted at a higher density.
Soil preparation
Prior to planting, use 300g of fertiliser containing phosphorus, potassium and trace elements or well rotted animal manure. Mix with topsoil and place at the bottom of the planting hole. Refill with topsoil and plant the trees deep enough to allow the root-ball to be covered completely with soil.
On Cununurra clay (in Kununurra) back-filling with sand will prevent air pockets. On large plantings this may not be practical. Successful establishment has been achieved in these situations by having the soil well watered before planting.
Planting
Mango trees should be planted as 4-18 month old seedlings or grafted plants. Planting time is generally from April to October when the plants are slow growing or dormant, but this varies according to location within Western Australia.
In Gingin, plant in early spring after the risk of frost has passed. This will allow young trees to withstand the hot summer and the cold winter following.
In the inland Pilbara, plant in March/April or August/September. Near the coast, plant from March to September.
In the Kimberley, the best planting time is May to August. This is particularly important at Kununurra and areas of similar extreme climatic conditions. A well developed root system is essential to ensure the trees’ survival from October to the onset of the wet season. Planting in January/February is another good planting time and should coincide with the arrival of the monsoonal rains. Spraying trees with kaolin (Sunstop®) has been shown to decrease the incidence of sunburn on newly planted trees.
At Broome, where conditions are less extreme, mangoes may be planted all year round. Ideally, trees should be sun-hardened before planting.
At planting, cut leaves to reduce the total leaf surface area to reduce the rate of water loss through transpiration. This helps reduce transplanting shock and the trees recover more quickly.
Spread a natural mulch, leaf litter, hay, bagasse or composted manure around the base of the tree to conserve moisture and suppress weeds. Avoid the mulch touching the trunk to minimise disease risk. If plants are established on trickle irrigation, black polyethylene mulch will help reduce water requirements and control weeds. In hot areas cover with a natural mulch to reduce heat absorption.