Macadamias are an expensive crop to establish and maintain; for this reason alone, marginal land should be avoided. Some of the most important attributes of suitable land are:
Soil depth must not be less than 0.5m to allow for prolific root development. We recommend a depth of 1.5m for optimal performance. Good drainage is essential within the rooting zone; Macadamias do well in a wide range of soil textures. Avoid valley bottoms in the Lowveld and Levubu. Avoid low-lying areas where cold air is dammed up by a timber plantation or natural bush. Slope, optimum range is from 0-15 percent. Some slope is desirable in that it facilitates air drainage. Over 15 percent slope the erosion hazard becomes increasingly severe and soil protection measures have to be of an appropriately high standard. Proximity to source of irrigation water, where static lift exceeds 100m, careful investigation of capital and irrigation running costs will be advisable.
Deep and well-drained soil, without any restricted layers are necessary for macadamia trees to grow in. Macadamia trees appear to be more tolerant to a wider variety of soil types. Optimal soil types to for planting Macadamia Trees in are Hutton, Inanda, Kranskop, Shortlands, Oakleaf and Griffen soil. Less suitable soil types (special management would be required) Clovelly, Glenrosa, Magwa, Fernwood, Valsrivier and Swartland soil. Soil types not suitable for planting Macadamia Trees in are Arcadia, Rensburg, Willowbrook, Estcourt, Avalon, Longlands, Katspruit and Kroonstad soil.
Ridging is most important if your topsoil is rather shallow (less than 500mm) and/or you have a drainage problem. If your farm has a slight slope to it and a good layer of top soil, it is not as important to make ridges.
Most farmers space there trees from somewhere between 3x6m to 4×8 meters. There are farmers who plant their trees 3 x 3m and then when the trees start growing into each other take out every second tree. These farmers will score in the early production cycle and get a higher return faster but will have a slightly higher initial cost and more work later.
The roots of the trees must never be in stagnant water. This will hurt if not kill the tree. Therefore it is important to have proper drainage on the farm. If the land is very flat and water tends to stagnate during rainy weather, you will need to ridge the land before planting.
When planting the trees, it is crucial to irrigate the little trees, especially if it is hot. In Mpumalanga the recommended amount of water for new trees is somewhere between 60-90 litres per tree per week for the first month. If it is hot and dry, it is more important to give water more often. Then you can divide the volume by the number of times you irrigate.
An established tree needs less water. Some farmers farm on dry land but most with irrigation systems. We refer to SAMAC for advice in your area.