The macadamia is a glossy broadleaf evergreen with leaves that resemble holly, flowers ranging from pink to white, and edible nuts that ripen at random times during the growing season.

Macadamia nuts (Macadamia integrifolia and Macadamia hybrids) are grown in Central (Kiambu

[7%], Muranga [17.2%], Nyeri [5.8%], Kirinyaga [4.4%]), Eastern (Embu [(36.5%)], Meru [11.8%],

Tharaka Nithi [5.5%], Machakos [7.8%], Western (Bungoma, Kakamega), Nyanza (Kisii, Nyamira),

Rift Valley (Baringo [(2.4%)], Trans Nzoia [(0.9%)], Nandi, Laikipia, Elgeyo Marakwet) and the

Coastal (Taita Taveta,) regions of Kenya (AFA, 2017) (Fig. 4). Emerging counties include Bungoma,

Kakamega, Taita Taveta, Nandi, Laikipia, Elgeyo Marakwet, Kisii, and Nyamira. This nut is second

in terms of value after coconut.

CULTURE

This is a self-pollinating tree that does not produce “true” from seed. While you may start with seed, it could take more than 10 years for your tree to mature, and it may or may not set fruit.

Alternatively, most people prefer to start with grafted plants to jumpstart the process and cut the maturity time in half.

While you may grow just one tree, macadamia is known for low yields, unless steps are taken to increase pollination. Macadamia nut yield is also greatly facilitated by the following factors:

• Planting more than one tree for cross pollination.
• Using quality grafted trees
• Having an ample supply of pollination enabling insects, particularly bees.

When a healthy tree reaches maturity, you can expect it to produce 30 kilograms of nuts per year, topping out at 30 to 40 feet tall and almost as wide, for luxurious shade in tropical and sub-tropical locales. The older it gets, the more your tree will grow, and the more productive it becomes.

What makes the macadamia nut so expensive?

It’s the resources and labor involved in cultivation, which lowers supply. The macadamia requires a great deal of water, especially when young. Their hard shells must be cracked open with great force, but without damage to the kernels inside, before being sent off for sorting, processing, packaging, and transport to market. All of this adds up!

A Note of Caution

According to multiple vet guides, the macadamia nut contains a level of toxicity that sickens dogs, so watch out.

PROPAGATION: TREE-STARTER OPTIONS

The macadamia does not produce true to seed, which means that while you may plant a ripe kernel, it won’t produce a plant that’s exactly like the parent. This is why commercial producers and nurseries who supply the public rely on cloning techniques to reproduce quality traits.

BUD GRAFTING

Budding is a technique in which a “scion” with desirable traits, in this case a bud, is placed into a slit in the branch of a host tree.

Here it establishes a root system, and at the appropriate time, the “nurse” branch is removed and the new plant flourishes on its own.

This is a labor-intensive horticultural process that comes with a considerable price, for a good head start.

GRAFTING A CUTTING

Grafting is the process of inserting scions, in this case cuttings, with desirable characteristics into sturdy rootstock.

It takes several years of excellent nursery care to be able to present an established, grafted plant for sale, so it’s also an expensive option that puts you ahead of the game.

ROOTING A CUTTING

Another way to start a tree is with a cutting from a young branch. Placing it in a potting medium enriched with a rooting hormone will encourage the wood to slowly grow roots.

Cuttings can be gathered to use for rooting or grafting.Alternatively, you may use the cutting as a scion and graft it to sturdy rootstock.

NURTURING A SEEDLING

If you purchase a seedling, it will most likely be about six inches tall and have at least one set of true leaves. Keep in mind that seedlings like this have been started from seed, and as we’ve said, results are unpredictable.

SOWING A SEED

You’ll find seed on the market, but again, results are questionable. You may also know where there’s a macadamia tree ripe for harvest in your area.

PLANTING FOR SUCCESS

With the information outlined above, you’re ready to shop at a plant nursery. If your goal is to produce substantial crop yields, we recommend starting with grafted plants with known characteristics and a proven track record.

SOIL TESTING

Macadamia has a “proteoid” root system comprised of compact root clusters that take up nutrients with great efficiency. You would be wise to have your soil tested by your local extension officer or any company that provides soil testing services like ours, to determine its acidity and nutrient content. Amend the soil as needed, to achieve a pH of roughly 5.5 to 6.5.

Remediation of the three essential macro-nutrients, NPK, may be recommended. There may also be micronutrient (copper, iron, manganese, molybdenum, zinc, nickel, and chloride) deficiencies to address.

PLANTING SEED, SEEDLINGS, CUTTINGS, AND NURSERY STOCK

The time to start thinking about planting that seed or a nursery seedling, cutting. By the rains in April you should have your macadamia seed or seedling already in the ground.

1. If you’re growing a tree from seed, nurture it until you have true leaves and a stem that’s roughly six inches tall.
2. Be sure to provide adequate drainage, as water logging may cause oversaturation, resulting in “damping off,” a condition in which the stem rots and the plant collapses and dies.
3. Transplant your seedling placing it into deeply worked soil. Be sure to maintain the same planting depth as the seedling experienced in the nursery, for a smooth transition. Alternatively, if you master the art of grafting, you may implant your seedling into quality rootstock.
4. If you are planting nursery stock that is well underway, get it into the ground as soon as possible after purchase.
5. Work the soil to a friable consistency, digging down at least twice as deep as the nursery container, and across twice as wide, to provide ample room for macadamia’s extensive root system.
6. If you choose to plant several trees, consider their mature dimensions, and add a minimum of 25 additional feet between each, to allow for adequate air circulation and root expansion.

WATERING REQUIREMENTS

The most crucial requirement for macadamia, especially in the sapling stage, is abundant water that drains well. Water freshly planted seedlings deeply, tamping down the soil a second time to remove any remaining air pockets, and maintain evenly moist soil until your plant begins to grow. Then, in the absence of a drenching rain, water weekly all year-round.

FERTILIZING

It is not necessary to fertilize macadamia at the time of planting you should wait about six months after planting, then apply a balanced fertilizer that contains 1% nitrogen or less, as is appropriate for a slow-growing plant. As your tree matures, you may conduct additional testing of your soil and the leaves of your tree to determine if you have an appropriate nutrient balance.

Depending upon the cultivar and how far along your plant is when you get it, your tree should start bearing fruit at about age 6 or 7.

PRO CARE TIPS

Congratulations! You have just planted your first macadamia. Now, here are some insider care tips:

1. Protect a young tree from damaging wind and/or frost by draping it with plastic sheeting.Wind protection is essential while nuts are forming, or they may drop prematurely.
2. Limit mixed planting to shallow-rooted cover crops, as deep-rooted plants will disturb the tree’s fragile roots and compete for essential nutrients
3. Keep the area beneath your tree free of debris, as it may invite insects and rodents seeking shelter. Pull weeds to reduce competition for water.
4. While planting deep-rooted plants too close to your tree is ill-advised due to its fragile and extensive root system, filling your surroundings with scented flowers that attract pollinators will increase your chances of achieving a flavorful and abundant fruit harvest.
5. A mature tree may withstand drought conditions temporarily, but a severe lack of water will take a toll on harvest quality and quantity of the produce.
6. As your tree matures, prune it. This allows sunlight to penetrate, and encourages a growth habit characterized by one central stem with protruding horizontal branches. Prune trees that don’t self-harvest (drop nuts), and those planted in containers, to a manageable height.

MANAGING PESTS AND DISEASE

The macadamia trees M. integrifolia and M. tetraphylla are not prone to pests and diseases. However, a tree may become vulnerable, especially in the event of weather extremes, or over- or under-watering.

Signs of trouble include discolored, disfigured, or dropping leaves and prematurely dropping fruit. And while some pests may make your tree their home, the damage they cause may not be extensive enough to cause large-scale damage to your tree or crop.

The following are some of the pests and diseases you may encounter while farming macadamia nuts.

BACTERIA AND FUNGUS

When a tree suffers an injury, like a cut, it may develop a wound that is vulnerable to bacterial and fungal colonization

RODENTS

This is not a rodent-resistant plant, so be sure to protect tender young shoots from their voracious nibbling. In addition, fallen fruit attracts rodents that won’t hesitate to feast upon them if they’re not promptly gathered.

HARVESTING BASICS

Your first harvest is certain to be an exciting event! All blossoms don’t produce nuts, but those that do set hefty green husks of about one inch in diameter that turn brown and begin to crack open when ripe.

Inside is a brown nut shell containing an edible kernel. Depending upon the variety or varieties you choose, they will ripen at any time from late fall through spring.

It may be tempting to shake your tree’s branches to make ripe fruit fall, but don’t, because you may also shake down unripe ones, and damage fragile branches.

Some folks place tarps beneath their trees to catch falling fruit, however, this may not be wise for two reasons: it impedes water penetration to the roots, and it retains rainwater that may rot ripe nuts that have fallen.

Macadamia is a unique nut that ripens continuously during the fruiting season, requiring multiple harvests. As mentioned earlier, some varieties self-harvest, falling to the ground for easy retrieval. Others must be gathered by hand off the branches; although they do drop to the ground, they don’t all drop at the same time as do those of cultivars in the self-harvesting group.

PRESERVING

Post-harvest, proper preservation and storage are essential to protect your crop from spoiling before you’re ready to use it.