Coffee is a genus of flowering plants whose seeds are used to make various coffee beverages and products. It is belongs to the family Rubiaceae.
They are shrubs or small trees native to tropical and southern Africa and tropical Asia.
Coffee ranks as one of the world’s most valuable and widely traded commodity crops and is an important export product of several countries. It is one of the most important cash crops in Kenya, where it is grown in both large and small scale plantations.
The trees produce edible red or purple fruits called cherries which contain two seeds, the so-called coffee beans, which are not true beans.
Coffee is mainly grown as a beverage, though the plant residues can provide fuel (coffee charcoal or wood) and a good mulch.
The main variety grown in Kenya is Arabica coffee (C. arabica).
Specific geographic conditions, sunshine, temperature, wind, precipitation and soil composition, need to prevail to guarantee an excellent quality and good yields from the coffee plants.
The ideal temperature range for Arabica coffee lies between 18 and 24 degrees centigrade. Maximum day temperatures should not exceed 30 degrees centigrade and night temperatures should not fall below 15 degrees centigrade.
Arabica coffee is normally grown at altitudes from 1400 to 2000 m with a rainfall of not less than 1000 mm per year. Where coffee is grown under conditions of minimum rainfall, mulching is essential to conserve moisture.
Robusta coffee is more resistant to pest infestation and is well adapted to warm and humid equatorial climates with average temperatures of 22-26 degrees centigrade, minimum not below 10 degrees centigrade, at altitudes of 100-800 m and well-distributed annual rainfall of 2000 mm or more. The ideal amount of rainfall lies between 1500-1900 mm.
Coffee prefers well-drained and airy soils, which drain freely and have a depth of at least 1.5 m and 3 m in drier areas.
Humus-rich, lightly acidic soils of pH range 4.4-5.4 are beneficial.
Land preparation & Planting
Propagation is done by seeds or by use of grafts.
While preparing the planting site, CLAMPDOWN 480SL is recommended. It is a non-selective herbicide which controls all kinds of weeds.
Dig holes of size 60 cm x 60 cm x 60 cm at a spacing of 2.75m x 2.75m for the traditional varieties. A closer spacing of 2m x 1 m on flat land for small holders without spray roads is recommended.
Fill the holes 4 weeks before planting with a top soil mixed with farmyard manure or well-rotted coffee pulp plus DAP. The fertilizer and manure should be mixed with HUMIPOWER, which increases nutrient uptake rate by the plants and stimulate growth among other benefits.
Spacing for “Ruiru II” is 2 x 2 m or 2 x 1 m giving a population density of 2,500 – 3,300 trees/ha for small holders.
Potted seedlings should be transplanted when they are about 30-40 cm high with maturing bark about 15 cm and 2-3 pairs of lateral branches at about 12-15 months old.
Mulching has several benefits to coffee e.g. conservation of moisture during dry spells, suppression of weed growth, nutrient supply, improvement of soil structure and water infiltration, checking of soil erosion and top soil temperature as well as reduction of pests’ incidence, e.g. thrips. It can be done using sisal waste, coffee pruning, and maize or banana trash.
Shade trees and windbreaks
Coffee grows best with shade trees, which reduce stress, e.g. due to adverse conditions like strong wind. At higher altitudes temporary shade trees may be phased out once the coffee is well-established. The shade trees should be planted earlier before coffee transplanting is done.
Pruning is essential in coffee production as it determines the shape of the tree, maximizes the amount of new wood for the next season’s crop, maintains a correct balance between leaf area and crop and prevents over-bearing, thus reducing biennial production or death of trees.
Weeds compete with the target crop for growth factors like nutrients, sunlight, space and water, as well as harboring pathogens which directly affects performance of the crop.
Spray CLAMPDOWN 480SL 150-300/20l, which is a non-selective herbicide used to control both broadleaved and grass weeds keeping the garden weed-free.
For an optimal production, the crop should be provided with a proper nutrition. This includes both macro and micronutrients which is achieved through application of both basal and foliar fertilizers.
Basal fertilizers are absorbed through the roots and include DAP, CAN, NPK. During application, it is recommended that the fertilizer (50kg) be mixed with HUMIPOWER 1kg, which improves nutrient uptake by the crop, adds organic matter into the soil, stimulates growth, and stabilizes soil PH. levels, among other benefits.
Manure could also be added, depending on the organic matter level of the soil.
Foliar fertilizers are absorbed through the foliage and are thus sprayed. They include OPTIMIZER, GOLDCHANCE SERIES, LAVENDER, LEGENDARY, DIMIPHITE and BIODISTINCTION, among others.
A proper nutrition also increases the crop’s resistance to infections and weather stress.
Common Pests & Disease Control
Coffee berry borer
This is the most serious pest of coffee in many of the major coffee-producing countries, whose losses can be severe, ranging from 50 to 100%. The adult is a tiny, cylindrical blackish beetle. The borers feed by tunneling in the tissues of the beans destroying them. Pupation takes place in the berry.
Symptoms of attack are one or more small round holes near the apex of large green or ripe berries, and the damaged beans, which have a distinct blue-green staining contain up to 20 grubs. Female beetles also attack young berries.
Coffee berry borer damage predisposes the coffee bean to fungal infection and hence contamination with mycotoxins.
Spray RANGER 480EC 30ml/20L or PROFILE 440EC 30ml/20l or PRESENTO 200SP 5g/20l
Antestia bugs (Antestiopsis spp)
These are major pests of coffee in East African countries.
The adult bug is shield-shaped, about 6 to 8 mm long and strikingly coloured dark brown with orange and white markings. They hide in berry or flower clusters. Females lay eggs in groups of about 12 on the underside of leaves.
They suck sap from tender leaves, petioles and berries. Severely attacked leaves and berries drop. The bugs also excrete honey dew on which sooty mold develops.
Spray PRESENTO 200SP 5g/20l or EMERALD 200SL 15ml/20l or RANGER 480EC 30ml/20l
Soft green scales
These are more serious on transplanted seedlings during the first 2 years in the field. These yellowish to greenish flat oval scales are about 5 mm in length and prefer to attack green wood and leaves, and usually appear as rows of flat oval green scales along main leaf vein and near tips of green shoots.
The scales cause damage by feeding on shoots, leaves and berries.
They produce large amounts of honeydew which attracts ants, and also covers the leaves and sooty mold develops on it causing the leaves to appear black and sticky.
Spray RANGER 480EC 30ml/20l or EMERALD 200SL 15ml/20l or LOYALTY 700WDG 5g/20l
Coffee thrips (Diarthrothrips coffeae)
The adult thrips are 1-1.5 mm in length and grey-brown in colour while the nymphs are wingless and yellow.
Both adults and nymphs feed on the underside of leaves, but in severe infestations they also attack the upper side of leaves, berries and green shoots.
Attacked plant parts show irregular grey or silvery patches covered by numerous tiny black spots, which are the excreta of the thrips.
In cases of severe infestation the leaves dry up and fall off.
Spray DEFENDER 25EC 40ml/20l or ALONZE 50EC 5ml/20l or PROFILE 440EC 30ml/20l
Coffee berry moth (Prophantis smaragdina)
The adult is a small golden brown moth with a wingspan of about 1.3 mm. The female moth lays scale-like eggs singly on or near green berries. The caterpillar/larva is reddish to pink in colour with dark markings on the back, and measures 13 mm when fully grown.
The larvae bore into green, half-grown berries, starting near the stalk and hollow them out. One caterpillar usually attacks several berries in a single cluster. Attacked berries turn brown to black. When one bean has been eaten, it leaves the berries and wanders over the cluster of berries joining them with threads of silk before boring into a second berry. Flower buds and the tip of suckers may also be attacked.
Spray SINOPHATE 750SP 20g/20l or RANGER 480EC 30ml/20l or PRESENTO 200SP 5g/20l
White coffee borer (Anthores leuconotus)
Adult beetles of the white coffee borer, also called white stem borer are about 3 cm long and have very long antenna. They are dark brown greyish in colour, the wing cases are greyish white with dark markings near the end.
The adult beetles feed on the bark of branches, causing little damage. Female beetles lay eggs on the trunks of trees usually at the base near the ground level. The whitish, legless larva burrows into the bark and the wood of the trunk and main roots. The larva pupates in a large chamber within the trunk. The attack by larvae causes serious damage, particularly if the trunks are almost ring-barked. Young trees may be killed.
Older trees wilt, turn yellow and produce a poor crop.
Symptoms of attack are round exit holes of the adult beetles in the trunk and wood shaving extruding from the bark or from the roots just below soil level.
Spray EMERALD 200SL 15ml/20l or LEXUS 247SC 8ml/20l or PRESENTO 200SP 5g/20l
Red coffee mite (Oligonychus coffeae)
The red coffee mite may be a pest of unshaded coffee in localised attacks during the dry season. They attack the upper surface of mature leaves and as a result, the upper surface of fully hardened leaves turn a rusty, purple or yellow brown colour. Under drought stress young leaves may also be attacked.
Spray ALONZE 50EC 5ml/20l or BAZOOKA 18EC 10ml/20l
Root-knot nematodes (Meloidogyne spp.)
Field symptoms are typically of stunted, poorly growing plants with yellowing leaves.
Infected root systems show characteristic knots or galls, whose severity varies with the degree of nematode infection, species and variety of plant parasitized.
Drench soil with ALONZE 50EC 10ml/20l or always mix basal fertilizer (50kg) with ADVENTURE 0.5GR 2kg.
Leaf skeletoniser (Leucoplema dohertyi)
The leaf skeletoniser is usually a minor pest but severe outbreaks could occur especially in nurseries.
The adult is a grey and brown moth with a wing-span of about 1.3 cm held at right angles to the body. They lay yellow-green eggs singly or in small groups mainly on the underside of leaves. The larvae feed on underside of the leaf, usually near the mid-rib leaving many irregular lace-like patches.
Spray ALONZE 50EC 5ml/20l or ESCORT 19EC 10ml/20l or SINOPHATE 750SP 20g/20l
Coffee leaf rust (Hemileia vastatrix)
Yellow to orange powdery blotches appear on the underside of leaves and subsequently, chlorotic patches appear on the upper side.
A major effect of coffee leaf rust is that it causes defoliation.
Under humid conditions, hyper-parasitic fungi such as Verticillium lecanii grow over the lesions, which produces a pale mycelial growth.
Spray GREEEN COP 500WP 50g/20l or JUPITER 125SC 15ml/20l or DUCASSE 250EW 20ml/20l
Coffee berry disease (CBD) (Colletotrichum kahawae)
It is also known as “coffee berry anthracnose” or “brown blight of coffee”.
The characteristic symptom is a progressive blackening of young, expanding coffee berries which begins as small water-soaked lesions that rapidly become dark and sunken. As they grow they cause the whole berry to rot. Under humid conditions, pink spore masses become visible on the surface of the lesion.
The coffee berry disease may also infect flowers under very wet conditions, and causes brown lesions on petals.
Spray GREEEN COP 500WP 50g/20l or KATERINA 720 SC 50ml/20l or COMPLIANT 560SC 40ml/20l
Armillaria root rot (Armillaria heimii)
Symptoms include wilting of leaves, death of verticals and subsequent death of affected trees. The root system of affected trees shows a white growth of the fungus beneath the bark.
In advanced stage of the disease the wood of the affected tree is decomposed into a white, wet mass with characteristic black zone lines running through the wood tissue.
Drench soil with PYRAMID 700WP 100g/20l or CHANCETYL ELITE 800WDG 100g/20l or GREENCOP 500WP 100g/20l.
Coffee wilt (Fusarium xylarioides)
The symptoms due to infection include wilting, chlorosis and defoliation of the aerial parts of the crop, and numerous vertical and spiral cracks in the bark of the trunk. Inspection under the bark, especially around the collar, shows characteristic blue-black streaks in the wood. Fungal fruiting bodies producing spores can be observed in the bark.
Infected berries turn red and appear to ripen early while seed infection causes blue-black discoloration of the parchment and silver skin.
Drench with GREENCOP 500WP 100g/20l or CHANCETYL ELITE 800WDG 10g/20l or GEARLOCK TURBO 250WP 50g/20l
MATURITY, HARVESTING & POST-HARVEST HANDLING
A coffee tree reaches maturity after 4 – 7 years, when it begins to bear fruit in clusters along its branches. These fruits are commonly referred to as cherries.
The fruit is initially green and turns red when it is ready for harvesting.
Beneath the cherries’ red skin is a pulp, an outer layer and a parchment-like covering the bean. Inside these layers are two oval shaped beans, with their flat sides facing each other
Harvesting time varies by region and altitude.
Only the ripe berries should be harvested because immature and overripe berries yield poor bean quality.
Coffee is harvested by hand by one of two ways, i.e., strip picking or selective picking.
Strip picking involves harvesting the entire tree at once by stripping all the beans off the branches, both ripe and unripe. This method is commonly practised for Robusta coffee. Machines can also be used to harvest Robusta coffee which simply shakes the trees knocking off all the cherries at one time.
Selective picking involves selecting only the ripe cherries, then returning to the tree several times over a few weeks to pick remaining cherries as they ripen. The method is more expensive due to the labor involved and is only used for Arabica coffee.
Coffee harvesting in Kenya is done by selective picking of the ripe berries.
The cherry is sorted out before pulping, which helps to remove the immature, diseased, insect damaged and dry berries as well as the leaves, twigs and other foreign matter. The sorted out berries are then ready for processing.
This must begin immediately after harvesting and involves the removal of husk and fruit from the beans and the subsequent drying of the beans to 11% moisture content. Delaying the operation for more than 48 hours causes the deterioration of the quality of the beans.
There are two major ways coffee is processed after harvesting, i.e., the Dry Method and Wet Method.
The Dry method, also called Natural Process, this is the traditional way of processing coffee. The harvested cherries are spread over a concrete or brick patio, in full sunlight, and raked at regular intervals to prevent the beans from fermenting. After 7 to 10 days, when moisture levels within the cherries have fallen to about 11%, the cherries are considered dry. The outer shell will have dried to a dark brown and become brittle. The dried cherries are then stored in silos.
The Wet method uses a pulping machine to remove the outer layers of the cherries from the beans within and this is done within 24 hours of harvesting. Cherries are carried by water, hence “wet method”, and washed through the pulping machine which squeezes the beans from the cherry pulp, the beans are then carried through washing channels which separates the lighter, immature beans from the heavier, mature ones. The beans are then stored in fermentation tanks for 12 to 48 hours during which time enzymes work to naturally separate the remaining outer layer from the parchment covering. When the process is complete, the beans must then be dried to 11% moisture content. Drying is either by sun on patios or by mechanical dryers.
Either way, the finished coffee is known as “parchment”, referring to the final layer which remains on the beans.
The chosen processing method has an integral impact on the flavor profile.
- Whenever doing foliar sprays, always mix the product(s) with INTEGRA 3ml/20l. This is a sticker, spreader and penetrant which helps in improving the products’ efficacy, giving more effective results.
- JAMBO CLEAN 100ml/20l is used to clean sooty mold which results after infestation with sap-sucking pests like scales.
- Alternation of various chemicals (especially fungicides and insecticides) throughout a crop’s season help in preventing resistance build-up by the pest, which could happen if only a single chemical was used.
- All basal fertilizers and manures should be mixed with HUMIPOWER, which adds organic matter into the soil, improves nutrient uptake, stimulates beneficial microbial activities, promotes electrochemical balance and stimulates plant’s development among other benefits.