By Samuel Munyiri
The avocado plant has seen admiration by many farmers who seek to grow the crop following an increasing local and export market, especially to China, the Middle East, and Europe.
This has led many farmers to seriously consider avocado farming. Middlemen have, as a result, sprung up and filled the growing and market spaces of the fruit, buying from growers and re-selling to export players.
Generally, when markets open for a particular crop, farmers tend to adopt its cultivation en masse until markets get saturated with the product. However, for avocado, the market is so large that there are few or no records of a glut. What people may argue about is fluctuating prices depending on who is buying and where.
Many farmers have even changed from traditional crops such as maize and tea to avocado, especially the Hass variety. To reflect this improved uptake of the crop, many nursery growers have increased avocado seedling production to match growing demand.
What then awaits many farmers, unknowingly, is the poor rate of establishment of the crop. This exercise demands expertise right from the onset, and this is particularly where many growers’ dreams shatter.
Good plans and visions are halted when many tree seedlings fail to establish, and those that do often show disturbed or poor growth, later stalling and eventually dying. Very few survive. This is sadly the story of many beginner avocado farmers who have heard about the potential riches of the crop and dared to begin the journey.
This piece seeks to explain why seedlings are lost at the point of crop establishment and what can be done to correct the problem.
To start with, deep soils that aerate and drain well are highly recommended for avocado cultivation. The avocado plant demands good root health, aided by soil that provides adequate air and drains excess water without stagnation around the roots.
The plant dislikes compacted soils that push out air, shallow rock bottoms, and hardpans that are difficult for roots to penetrate. Lack of air and excessive wetness that linger too long create conditions of root hypoxia, a condition similar to suffocation in animals. This triggers weakness and predisposes the plant to root diseases.
With this said, the biggest challenge preventing successful establishment is a condition of the rooting system called the “J” root. This is an abnormal growth orientation of the taproot, where it grows sideways or curves upward instead of vertically downward.
The taproot fails to seek depth and anchorage. This results in plants with roots concentrated near the soil surface, where water is quickly lost through evaporation and root desiccation. Plants become exposed to frequent fluctuations in soil moisture.
The result is plants showing signs of water stress whenever irrigation is reduced, or plants requiring repeated irrigation at short intervals. The strain is usually felt by farmers with inadequate water sources, limited labour, or high energy bills for those using powered irrigation systems. Farmers unable to keep up with these demands are often forced to abandon the dream of harvesting avocado riches and instead face desperation and regret.
Many readers may not understand how poor root behaviour can destroy farming dreams, but in avocado farming it certainly can. A proper taproot grows long and vertically downward, providing a large surface area for secondary roots to develop and thrive.
This expands the feeding area of the plant and strengthens anchorage. It also allows the root system to access deeper soil layers where evaporation is minimal, enabling plants to survive drought. The “J” root prevents these advantages.
What causes the “J” root?
During seeding, the avocado seed is placed in polyethylene nursery bags and shallowly buried in soil. Germination sends the taproot downward, but upon reaching the bottom of the plastic bag, the root is blocked and redirected sideways or upward, forming the characteristic “J” shape.
This becomes the origin of the problem. Usually, this issue does not correct itself once the affected seedling is transplanted into the main field. Many farmers buying potted seedlings do not realize the future challenges because the seedlings appear healthy while irrigation water remains trapped within the nursery bag and close to the roots.
Problems begin when seedlings are removed from the bags and transplanted into field conditions where supervision is less intensive than in the nursery. The transplanted seedlings often die in large numbers, especially during the dry season when irrigation is insufficient.
Seedlings affected by the “J” root require frequent watering at short intervals. This routine exhausts growers physically, mentally, and economically. Many affected farmers eventually withdraw and abandon the crop because they become overwhelmed by the demands of a weak planting.
Way forward
Farmers are advised to inspect the bottom of avocado seedlings for “J” root behaviour and trim the root at the point where the curve forms before planting. The soils should be loose and free from rocky bottoms or hardpans.
Nursery operators also need proper training so they can guide buyers appropriately. Another important rule during planting is not to bury the seedling deeper than the original root zone level.