The Multi-billion Industry - Growing AVOCADO
GENERAL DISTRIBUTION In Kenya is found mainly in the Western, Central and a little bit at the Coast.
CLIMATIC CONDITIONS, SOIL AND WATER MANAGEMENT Depending on variety, avocado grows well from 0-2100 m above sea level (asl). The varieties 'Tonnage', 'Simmonds', 'Booth 7&8' are suited to lowland areas between 90 and 800 m asl. 'Hass' and 'Nabal' are suited to altitudes 800-2100 m asl. 'Fuerte' and 'Puebla' are suited to altitudes 1500-2100 m asl.
Avocado grows successfully on many types of soil provided they are deep, with good water holding capacity and free draining. Water logged or saline soils are unsuitable because avocado plants are sensitive to excessive soil moisture and high salinity. The optimum pH is 5.5-6.5. Temperatures between 16 and 24°C are good for growing avocados. Maximum temperature for avocado is 33°C. Above this temperature avocado fruits and trees can be damaged. High temperatures and direct sunshine can cause sunburn damage to exposed fruit. Avocado will not grow where frost can occur. An annual rainfall 1200 mm is optimal for good production. Water requirements are not less than 1000 mm/year. If supplementary water is required not more than 50 mm at a time may be applied. Climatic conditions with alternating dry and rainy seasons are best for avocados.
VARITIES INCLUDE: 'Fuerte'. Hybrid of Guatemalan and Mexican races with thin skinned green-pebbled fruit of very good flavour. This variety has many lines with different shapes; the pear shaped fruit is preferred in the export market. Matures 6-8 months after flowering. 'Haas'. Vigorous grower and bears medium-sized, rounded, rough-skinned, black fruits. Propagates well. Matures 8-9 months after flowering. 'Nabal'. Bears fruit in alternate years. Its green fruits have a good flavour. Matures 8-9 months after flowering. 'Puebla'. Spreading, dark green tree bearing deep purple to maroon round fruit. This variety is normally used as a rootstock. Matures 5-7 months after blossoming. Others: 'Reed', 'Simmonds', 'Booth 7&8', 'Pinkerton', 'Bacon', 'Lula' and 'Taylor'
'Fuerte' is the main variety grown in Kenya. The variety 'Hass' is developing strongly, especially among small growers. These two varieties are grown for the export market. Other varieties ('Reed', 'Booth 8', 'Puebla', 'Pinkerton', 'Simmond', etc.) are grown but not exported (Mugambi, 2002)
PROPAGATION AND PLANTING Select healthy, egg sized seeds and plant them in boxes or seedbeds. Immediately after germination transplant the seedlings into 4 litre pots, tins or polythene bags. Water them regularly until they are pencil thick. Grafting should be carried out when the seedling reaches pencil thickness. Wedge grafting method is most successful. Grafting should be done at the point where rootstock is soft. The scion should be dormant at the time of grafting and should match the size of the stock. Wrap the grafting point thoroughly to exclude water from the union and to prevent it from drying out.
LAND PREPARATION The fields should be cleaned by removing tree stumps, bushes and perennial weeds. Then the land should be mowed or cultivated.
PLANTING OUT Generally a spacing for pure stands of avocadoes of 9m x9m will be suitable. Dig holes of 60cmx60cm by 60cm deep keeping the top soil and the sub soil separate. Mix the top soil with 1 bucket (20 litre) of well rotted manure or compost and 1-2 handfuls of Mijingu rock phosphate. Remove the plant from its pot keeping the root and soil structure intact (easiest if it has been properly wetted ahead of time) and plant out using only the topsoil mixture to fill the hole. The subsoil may be used to make a basin around the tree. Water the seedlings immediately after planting if it is not in the rainy season. Shade the young plants with banana leaves or similar material after planting and when they are putting up a new flush. If planted in a windy area, a windbreak will be necessary to protect the plants from leaning to one side and to help prevent leaf shedding fruit drop and bruising.
MANURING One avocado tree can yield 250-300 kg of fruit per harvest season. This causes a high demand on soil nutrients. To determine the right amount of manure to apply the soil should be tested annually, otherwise the following table can be used as a guide for organic farmers for manuring individual trees: (FIND THE ATTACHED FOR MORE DETAILS )
PRUNING Initial pruning may be done to give the tree a good shape. Otherwise pruning is limited to the removal of dead wood and parasitic plants.
- Remove all sucker and dead branches from main trunk branches.
- Prune canopy to keep the tree to a height of 5-8 m and for ease of picking. The tree is very susceptible to sunburn, therefore pruning should be minimised.
- Prune the larger tree roots by cultivating to a depth of 50 cm around the edge of the tree canopy
The area around the tree should be kept clean by weeding and removal of all fallen fruits. Harvesting Harvesting starts at 3-4 years from planting but a good yield is obtained from the 6th year onwards. It is not easy to tell when the fruits are ready for harvesting unless they are of the varieties that change colour at maturity. Harvest a sample and keep at room temperature. If they soften within 7-10 days without shrivelling then the fruit of that age are ready for harvestin
Manuring Specifications (Find attached )