How To Install Rain Hose Kits

Grekkon Limited’s manual on how to install rain hose kits in Kenya is an easy to read step by step guide. It details every aspect of rain pipe assembly in the farm to provide understanding to farmers. As the pioneer of rain hose kits in Kenya, we are keen to that farmers receive the full benefit of rain pipe irrigation

What is the price of a rain hose irrigation kit?

Rain hose pipes work under high gravity pressure (from 6M or 0.6bar), and with high volume water pumps. The discharge rate of the water pump is from 40 cubic litres per hour. These water pumps are surface solar, electric, petrol or diesel powered    

A well connected rain hose pipe

How To Install Rain Hose Kits

1. Trench where the poly vinyl chloride (PVC) main line will be laid. This is not necessary for the high density polyethylene (HDPE) which are surface pipes.  PVC pipes are sub-surface pipes because they have no UV-treatment, and will thus degrade easily under the sun. HDPE pipes have UV treatment and will be surface pipes
2. Connect the  PVC or  (HDPE) main line to the water pump or high tank. This pipe evacuates water from the source to the farm and is the largest in diameter. The larger the pipe diameter, the more the water it delivers. .
3. Join the HDPE or PVC sub-main line to the main line. The sub-main line is smaller in diameter, and so carries less water. It is joined to the main line through PVC or HDPE accessories such as; tees, elbows, saddle clamps, adaptors or valve sockets
4. Connect the rain pipe to the sub-main line or the main line where a sub-main line does not exist. This is done with a rain hose connector or a saddle clamp
5. Spread the rain hose along the length, and close the terminal end with an end cap
6. Connect one rain pipe to another with a connector

 Rain hose fittings from left to right: end cap, connector, rubber, and ball valve

A drilling tool is the only tool used when installing a rain hose kit. This is to create an opening on the main or sub-main line to insert the rain pipe ball valve

How To Install rain Hose Kits

Rain hose irrigation system requirements

• The system requires a pressure head of 30M, and above
• When using a water pump to power the rain hose irrigation kit, the discharge rate should be from 45 cubic litres per hour
• The rate of water discharge is determined by the diameter size, and number of pores on the rain pipe. For instance, a rain pipe with 5 holes per cluster discharges less water than the one with 7 holes in a cluster
• It irrigates in opposite directions at a radius of 3M for the 32mm pipe, 5M for the 40mm pipe, and 7M for the 50mm pipe
• The vertical height of this water jet is 1M

Rain Hose Versus Drip Irrigation

1. Rain pipes irrigate in an overhead fashion, drip lines irrigate to the root zone
2. Drip tapes are water efficient, rain hose kits require large water volume
3. Rain pipes have a higher pressure requirement than drip pipes
4. Drip lines have emitters, while rain hose kits have pores done with nano technology
5. The discharge rate for drip lines is 1.2 to 4 litres per hour per emitter, while the rain hose pore’s is from 7 litres per hour per emitter
6. The cost of a drip kit installation per acre is from Kes 100,000, while the rain hose is from Kes 75,000
7. The rain hose pipe’s minimum diameter is 25mm/ 3/4″, while drip tape’s is 8mm

Advantages Of A Rain Hose

• water saving and cost effective
• It is easy to install, use and maintain
• Ran hose nanotechnology punched holes are less prone to clogging
• It is used in a broad range of crops
• Rain hose pipes are light and easy to move about
• It irrigates uniformly
• It works under both low gravity and high water pump pressure

Rain hose irrigation system is for the following areas and on these crops

1. Crop nurseries; vegetables, fruit trees, forestry
2. Short vegetable crops (knee-high and below); cabbage, lettuce, broccoli, kales, spinach, collards, broad beans, carrot, strawberry, and others
3. Pasture; grass and legumes

When choosing the crop to irrigate using this method, consider its susceptibility to foliage fungal infections predisposed by leaf surface wetness. Tomato, potato, peppers, peas, green beans, and chili easily succumb to foliage fungal infections when overhead or a rain hose system is used for a long time

 Pasture irrigation with a rain hose

How To Install Rain hose Kits

FAQs

a. What is the difference between a rain hose irrigation system and a sprinkler system?

• The technology. The rain pipe irrigation system is designed using nano technology
• The mode of spray. A sprinkler sprays its water in one direction, a rain hose pipe sprays in 3 directions (vertically, horizontally, and diagonally)
• Placement. A sprinkler is placed upright on the surface or sub-surface (for pop up sprinklers). A rain hose is laid on the ground

b.  What is the pressure in a rain pipe?

The minimum operating pressure is 30M head / 3 bars

c. What is the spacing for rain hose irrigation?

The distance from one rain pipe to another is from 1.5M depending on the operating pressure, and pipe diameter

Grekkon limited is the largest supplier and installer of rain hose irrigation systems in Kenya, and in the east and central Africa region

Irrigation Company In Nairobi

In 2017 through 2018, Grekkon Limited was an irrigation company in Nairobi servicing small to medium scale holders. The company’s focus was on irrigation and allied services. these are;

• Irrigation. drip, overhead, and sub surface irrigation systems

• Dam liners. for irrigation water harvesting and conservation
• Greenhouses. steaal and wooden types
• Borehole drilling
• Water pumps. solar, electric, petrol and diesel types
• Solar dryers. for post harvest crop loss management
• Agricultural nets. bird nets for bird pests, shade nets for , and insect nets for insect pests
• Trays. seedling trays for seedling propagation, and hydroponic trays for hydroponic fodder production
• Coco peat. a non soil media for use in seedling trays
• Mulch paper. to manage field water loss through evaporation, weed and pest control

While improving the clients’ overall yield, and income from farming. The company focuses on this smallholder, and medium holder niche because of the presence of large irrigation service providers in the country. These companies clientele are the large ornamental, cereal and vegetable growers. Smaller growers had to fend for themselves because they were never a priority for these large corporates. A hallmark of the company is the free 4 month agronomy training programs for all their farmers. Grekkon Limited is the only company that offers this free service to farmers in Kenya

The company organizes ‘training days’ in various regions of the country. Growers come to learn of new and existing technologies.

The other objective was to do further by offering expert irrigation, greenhouse, water pumps, and dam lining expertise to these small scale to medium scale commercial farmers, who had no professional entity to consult for such. This was through physical site visits to carry out assessments, provide advice, and carry out irrigation project reviews afterwards. And so, Grekkon Limited – Irrigation Hub was born. It is headquartered in Athi River, with outlets in other key agricultural zones in Kenya

Two years after establishment, Grekkon won the coveted Most Preferred Irrigation Systems Company of the Year award in 2019. This was at the prestigious Agribusiness Excellence Awards ceremony. The farmers in their votes had finally spoken!

Irrigation Company In Nairobi

1. Irrigation Products

1. Drip kits. For both vegetable and fruit tree/ forestry irrigation. This includes; drip tape, 16mm HDPE pipe, starter connectors, off-takes, drip to drip connectors, button or online drippers, and end caps
2. Rain hose kits. It has; rain hose pipe, off-takes, connectors, and an end cap. Rain hose kits are best utilised where drip irrigation systems cannot be installed such as is pasture, or crop nurseries
3. Sprinkler systems. There are various types;

3.1. Pop up sprinklers. These are sub-surface sprinklers for lawns, golf course, football pitches, and gardens

3.2. Rain gun sprinklers. These are metallic high pressure, high volume sprinklers for use in all crops. They are well utilised in larger acreage because they have a wide area of spray

3.3. Impact sprinklers. They are plastic and range from 1/2″ to 1″. Mostly used to irrigate small vegetable farmes, or pasture

3.4. Meganet sprinklers. These are plastic sprinklers that range from 1/2” to 1”. They are a suitable alternative to impact sprinklers

3.5. Butterfly type sprinklers. They are for lawns and small gardens like the kitchen garden

3.5. Micro sprinklers. They irrigate individual fruit tree plants, just like button drippers. However they cover a wider area, and provide better humidity around the crop’s root zone

In this video below, a smallholder farmer who was an early adapter of Grekkon’s rain hose kits. She speaks about her growing experience

4. Misters and foggers. Used in greenhouses for seedlings watering, and humidity control

Solar water pumps by Grekkon Limited

5. Water pumps;

As an irrigation equipment supplier, every irrigation system is backed by the following types of water pumps to draw water from a source, to supply the irrigation system

i. Solar water pumps. These are either surface or submersible types. Submersible water pumps work under water, while surface water pumps are ground based

ii. Electric water pumps. Like solar water pumps, they’re surface and submersible options

iii. Diesel generator water pumps. They run on diesel powered engines. They are portable or fixed types. The latter are larger in size

iv. Petrol water pumps. They run on petrol powered engines, and are smaller than diesel water pumps

6. Irrigation pipes

6.1. HDPE pipes from 16mm through 280mm diameter. The pipe thickness is from PN6 through PN25

6.2. PV pipes from 20mm through 280mm diameter. The pipe thickness is from PN6 through PN25

6.3. Suction pipes for supply with water pumps

6.4. Delivery pipes as either canvass or PVC material

Irrigation Company In Nairobi

Water pump accessories

Accessories that accompany motor powered pumps are; foot valves, clips, suction pipes, adaptors, splicing kits, control boxes, invertors (for DC to AC converstion) cables,  cable ties, solar panels (for solar pumps), and a solar panel support structure

Accessories that accompany motor powered pumps are; foot valves, clips, suction pipes, and adaptors

Every irrigation system has a main, and/ or sub-main pipes. We advice on the right pipe thickness, size and type based on

• Land size; determines pipe size. Large pipes for large acreage. Our pipe sizes range from 16mm to 180mm in diameter
• Irrigation system adopted; any of the 1 to 3 above
• Land ownership system; leased or owned? HDPE for the former, PVC for the latter

These pipes have specific fittings which are; elbows, tees, valve sockets, ball valves, couplings, adaptors,sockets,saddle clamps, and end caps by type and size

Drip irrigation system under installation by Grekkon Limited using PVC pipes as main and sub-main lines

Irrigation Company In Nairobi

Installation Service

Our irrigation service team conducts systems installations service in east Africa. We offer advisory services to manage the system well for many years

A client’s irrigation system installation by a company technician

Irrigation Company In Nairobi

Key Attributes

Innovation

Grekkon Limited in its innovation introduced the rain hose irrigation system. This new product solved many irrigation challenges for commercial vegetable and corn farmers. The company is the market leader in research and commercialization of natural solar dryers, each unit designed to meet the product or market drying requirements

Today, Grekkon Limited is the largest supplier of natural solar dryers within the east Africa community states

In 2024, Grekkon Limited introduced the first color coded drip tapes in the Kenyan market

Team

Grekkon Limited’s resounding success is largely due to its team of field professionals who provide engineering, commercial, and technical services

Country Wide Presence

As an major irrigation company in Kenya, Grekkon Limited has offices in; Athi River, Nairobi, Kisumu, Eldoret, Nyeri, and Nyahururu

Metallic Greenhouse Price In Kenya

Every metallic greenhouse price in Kenya by Grekkon Limited is determined by the greenhouse type, and size. All metallic greenhouses in Kenya by the company are made from galvanised steel. They are built to last for decades under intense crop production

Metallic Greehouse Price In Kenya

Our metallic greenhouse price in Kenya is provided in the tabulations below by cost and size for galvanized metallic greenhouse tunnel-type structures. Each unit has a drip irrigation kit, side roll-ups, and an entry pouch. We offer a crop support structure, a 1,000L tank, PPE kits, fertilizer, and seeds package at an extra cost. Consideration is made for a grower’s greenhouse budget. These prices include all greenhouse materials in Kenya

Completed units of metallic greenhouses by Grekkon Limited in Heni area, Nyandarua county

How much does a metallic greenhouse cost in Kenya?

A. Small

B. Medium

C. Large
From 800M square. Kes 900 per meter square. We customise our price according to size, and your greenhouse budget

Metallic Greenhouse Price In Kenya

5 Key Factors That Determine Greenhouse Cost

1. unit size. The larger it is, the costlier it becomes for the reason that it take in more material and labour. The choice a greenhouse of size is determined by; land area, water availability, and a grower’s budget
2. design. A tunnel type greenhouse is less costly than a vented type. This is because the latter has a larger roof surface area. Tunnel type greenhouses are for cooler highland locations, while the vented types are for warmer mid to low altitude areas. co-joined units are less costly than single units. For intance, 3 units measuring 30M x 8M built separately are more expensive than contructing them as one co-joined unit measuring 30M x 24M
3. greenhouse construction frame material of the unit. Grekkon Limited as a top greenhouse construction company in Kenya, has an option of a low cost greenhouse constructed from timber. This is referred to as a wooden greenhouse, or the option of the more pricey metallic greenhouse. Both serve the same purposes
4. frame treatment undertaken. Timber for greenhouse construction in Kenya is either treated with light organic solvent preservative (LOSP), or with used motor oil. These treatments protect the timber from termite attack. LOSP treatment is costlier, and preserves the wood longer. Motor oil has to be re-applied every so often and should not be in contact with the crop. Steel is either galvanised with zinc, or an aluminum paint coat is applied on the surface. In this too, the former treatment is costlier, and remains for long
5. greenhouse crop type. our greenhouse construction cost in Kenya for each of these types is determined by the crop type. For instance, an indeterminate crop that requires an internal crop support system will have a more costly greenhouse than a short strawberry crop. The greenhouse installation cost of a plant propagation unit with misters and foggers is higher than a herbs and spices unit without such

Metallic Greenhouse Price In Kenya

These are the materials used in metallic greehouses in Kenya installations

I. UV treated greenhouse polythene with anti drip properties

This is the key material that protects the crop from the elements of weather; sun, wind and rain. It creates the ‘greenhouse effect’, and minimises disease and pest incidences on the crop. It is either clear or yellow in color. Clear greenhouse polythene for fruiting crops, or in ornamentals, bi or multi colors. This is because it allows in more light which these need for photosynthesis, the process that makes food for the plants. Yellow is for vegetative crops, and mono color ornamentals. In mono color ornamentals, it intensifies the color

II. Galvanised steel bars

They provide structural support to the greenhouse, and also to the crop as ‘crop support structures’ for tall indeterminate crops such as; tomato, peppers, and cucumbers

III. UV treated high density insect nets

These nets keep away insect pests. They are for self pollinating (do not require external pollinators such as insects and birds) greenhouse crops

IV. Bird nets

These are only used in greenhouse crops that require insect pollination from bees, butterflies, hornets and many other pollinating insects. They allow in the insects, but keep away bird pests. An example of such a crop is strawberry

V. Profiles

They are screwed onto the galvanised steel bars so that the greenhouse cover is tucked in them

VI. Wiggle wires

Once the greenhouse cover is tucked in the profile, wiggle wires keep it in place so that it is not removed by wind or other physical force. Wiggle wires have a plastic covering to prevent damage to the greenhouse paper the are in direct contact with

Wiggle wires hold in place a clear greenhouse polythene sheet tucked in a profile

VII. Screws

The join the profiles to the galvanised steel structure

VIII. Concrete

This is what supports the metallic greenhouses in Kenya structures on the ground and keeps them upright

Humidification through misters in a seedlings propagation greenhouse

Successful greenhouse farmers in Kenya grow both none food and food crops in our metallic greenhouses. Common greenhouse food crops are; tomato, peppers, strawberries, and cucumber.  Galvanised steel bars, insect netting, screws, and profiles are our greenhouse construction materials. With labor addition, all now constitute your final greenhouse cost

Grekkon Limited’s metallic greenhouse price in Kenya will include; a drip irrigation system for crop production, or a misting/ fogging system for seedlings propagation, and labour. Sprinkler irrigation systems are not installed in greenhouses

A bird’s eye view of a metallic greenhouse for seedlings propagation under construction by Grekkon Limited at the ICIPE institute in Kasarani area, Nairobi county

Types Of Dam Liners

As a dam liner company, Grekkon Limited supplies and installs 3 types of dam liners in Kenya by thickness, and 2 types of dam liners by material. In this article, we answer many water harvesting using dam liners questions posed to us by growers

1. What type of dam liner is best?

1.1. Types of dam liners in Kenya –  by material

• High density polyethylene (HDPE) dam liners

This is what we supply and install most. This is because it is thin and lightweight which makes it easy to carry. They are tough with high tensile strength, hard to puncture, and stiff, which makes them less prone to sudden length tears. However, this stiffness makes welding more difficult. HDPE dam liners have the best UV resistance, and are safe for the environment because they do not emit chemicals. Their disadvantage is that they’re more difficult to repair when perforated. Our HDPE dam liners are in rolls from which we cut and tailor weld it to a water pan’s specifications

A HDPE dam liner installed by Grekkon Limited in Vihiga county, Kenya

• Polyvinyl chloride (PVC) dam liners

We supply and install these but at a lessor scale. PVC dam liners are highly flexible, impermeable and tough. They are heavier than HDPE dam liners, but easier to weld as the material joins together more easily. They have the best resistance to chemicals and acids and so they are not easily corroded. This makes them the most suitable for land fills and chemical containment sites. Our PVC dam liners are factory fabricated panels that eases installation. The downside with PVC dam liners is environmental safety because they release chemicals as the PVC material degrades. This in the long-term is toxic to fish

• 

  A PVC dam liner installed by Grekkon Limited in a water pan in Kibwezi, Kenya

• Low density polyethylene (LLDPE) dam liners

They are made from the same plastic as HDPE dam liners, and so share similarities. Being less dense than their HDPE cousins, they are softer, more flexible and more pliable. Being softer makes them less susceptible to stress cracking. High flexibility allows for easier under installation, and molding them around corners, nooks and crannies. Pliability means they conform best to rough terrain with little wrinkles

An LLDPE liner in a large water pan

1.2. Types of dam liners in Kenya – by thickness

• 0.5mm / 500 microns. This is for smooth surfaces and to hold low water volume (5,000 cubic liters and below)
• 0.75mm / 750 microns and 0.8mm / 800 microns. Works well in rough surfaces with few stones or murram. It will hold medium water capacity
• 1mm / 1,000 microns. Best for stony or rocky surfaces, and high capacity
• 1.5mm / 1,500 microns. Works on surfaces that the 1mm will not, and holds ultra high water volumes

2. Which is better: PVC or HDPE dam liner?

HDPE is better because it has greater tensile strength, and does not contaminate the environment

3. What is a good thickness for a dam liner?

The choice of thickness is determined by the surface and water volume. For instance, a 0.5mm dam liner is more appropriate for a concrete water tank holding 100 cubic litres than a 1mm dam liner

4. What are the 2 main types of dam liners?

HDPE and PVC dam liners are the most common dam liners in Kenya

5. How long does a dam liner last?

This depends on the thickness, material type and use. As a guideline though, 0.5mm thick dam liners last to 15 years, 0.75mm to 25 years, and 1mm to 36 years

6. Can I put a new dam liner over an old one?

The simple answer is yes, but remove any liquid, and solid debris on the old liner’s surface. Note that once the new one is placed, you cannot shift the old liner without affecting the new one. The new dam liner is not joined to the old dam liner in any way

7. How often do dam liners need to be replaced?

So long as the dam liner is functioning well, it is unnecessary to remove it. There is no replacement timeline

8. What is the best liner for a large water pan?

Large is relative. But for any water reservoir holding beyond 5,000 cubic litres, we recommend the 0.75mm or the 1mm thick dam liners

9. How do you hold a dam liner in a water pan?

There are 2 ways.

9.1. Trenching

This is where a 2 feet deep by 1 foot wide trench is excavated all round the circumference of the water reservoir. This trench is 0.75M to 1M from the edge of the water pan. The dam liner is tucked in here then covered with soil, gravel or rocks/ stones

The edges of a newly installed  HDPE dam liner in a water pan tucked in a trench and covered with soil

9.2. Sand bags

Bags filled with soil, sand or gravel are laid on top of the dam liner edges to anchor it in place

The different types of dam liners does not affect the holding method

10. Can you join 2 dam liners together?

Yes. Pieces of dam liner welded together make a continuous sheet

11. Can you glue 2 dam liners together?

The best way to join dam liners is by welding because it is permanent

12. Can you cut a dam liner?

Yes. We cut and weld together dam liner sheets from large rolls to tailor it to the water pan’s dimensions

13. Can you put gravel on top of a dam liner?

Yes you can especially if it is for support on the edges

What to consider when choosing a dam liner

• The surface texture. Install a thicker liner for rougher surfaces
• Water volume. The larger it is, the thicker the dam liner
• Purpose. If it will hold chemicals or acids, then the PVC dam liner is best because it is the most resistant

Small Irrigation Equipment Supplier

Grekkon Limited is a small irrigation equipment supplier in east Africa. Domiciled in Kenya, we serve farmers in; Cameroon, DRC, Ethiopia, Kenya, Nigeria, Rwanda, Somalia, South Sudan, Tanzania, Uganda and Zambia.

Our irrigation materials, tools and equipment vary with the system adopted by a grower. Below is our irrigation equipment list

Double emitter drip tapes pioneered in Kenya by Grekkon Limited

Small Irrigation Equipment Supplier

Types of Irrigation Equipment

1. Drip kits. For both vegetable and fruit tree/ forestry irrigation. This includes; drip tape, 16mm HDPE pipe, starter connectors, off-takes, drip to drip connectors, button or online drippers, and end caps
2. Rain hose kits. It has; rain hose pipe, off-takes, connectors, and an end cap. Rain hose kits are best utilised where drip irrigation systems cannot be installed such as is pasture, or crop nurseries
3. Sprinkler systems. There are various types;

3.1. Pop up sprinklers. These are sub-surface sprinklers for lawns, golf course, football pitches, and gardens

3.2. Rain gun sprinklers. These are metallic high pressure, high volume sprinklers for use in all crops. They are well utilised in larger acreage because they have a wide area of spray

3.3. Impact sprinklers. They are plastic and range from 1/2″ to 1″. Mostly used to irrigate small vegetable farmes, or pasture

3.4. Meganet sprinklers. These are plastic sprinklers that range from 1/2” to 1”. They are a suitable alternative to impact sprinklers

3.5. Butterfly type sprinklers. They are for lawns and small gardens like the kitchen garden

3.5. Micro sprinklers. They irrigate individual fruit tree plants, just like button drippers. However they cover a wider area, and provide better humidity around the crop’s root zone

In this video below, a smallholder farmer who was an early adapter of Grekkon’s rain hose kits. She speaks about her growing experience

4. Misters and foggers. Used in greenhouses for seedlings watering, and humidity control

Solar water pumps by Grekkon Limited

5. Water pumps;

As an irrigation equipment supplier, every irrigation system is backed by the following types of water pumps to draw water from a source, to supply the irrigation system

i. Solar water pumps. These are either surface or submersible types. Submersible water pumps work under water, while surface water pumps are ground based

ii. Electric water pumps. Like solar water pumps, they’re surface and submersible options

iii. Diesel generator water pumps. They run on diesel powered engines. They are portable or fixed types. The latter are larger in size

iv. Petrol water pumps. They run on petrol powered engines, and are smaller than diesel water pumps

Small Irrigation Equipment Supplier

Water pump accessories

Accessories that accompany motor powered pumps are; foot valves, clips, suction pipes, adaptors, splicing kits, control boxes, invertors (for DC to AC converstion) cables,  cable ties, solar panels (for solar pumps), and a solar panel support structure

Accessories that accompany motor powered pumps are; foot valves, clips, suction pipes, and adaptors

Every irrigation system has a main, and/ or sub-main pipes. Our irrigation pipes are HDPE and PVC. We advice on the right pipe thickness, size and type based on

• Land size; determines pipe size. Large pipes for large acreage. Our pipe sizes range from 16mm to 180mm in diameter
• Irrigation system adopted; any of the 1 to 3 above
• Land ownership system; leased or owned? HDPE for the former, PVC for the latter

These pipes have specific fittings which are; elbows, tees, valve sockets, ball valves, couplings, adaptors,sockets,saddle clamps, and  end caps by type and size

Drip irrigation system under installation by Grekkon Limited using PVC pipes as main and sub-main lines

Small Irrigation Equipment Supplier

Installation Service

Our irrigation service team conducts systems installations service in east Africa. We offer advisory services to manage the system well for many years

A client’s irrigation system installation by a company technician

Solar Dryers For Coffee In Kenya

Solar dryers for coffee in Kenya by Grekkon Limited improve the drying efficiency of harvested coffee cherry. In Kenya, harvested cherry is largely manually open dried which takes 10 – 14 days depending on the location and the prevailing temperatures. Open coffee drying is done on wooden raised table structures with a wire mesh bed laid out where the coffee cherry is spread thinly. The coffee cherry is dried by direct solar radiation and wind movement

Cost of solar dryers for coffee in Kenya

The overall cost of a solar dryer depends on the size. The average price of a large solar dryer for coffee in Kenya is Kes 1,200/M square

Challenges of open coffee drying

• it is labour intensive. This is needed to turn it over every 45 minutes to 1 hour on the bed to ensure eveness of drying, covering it in the evening or on rainy days with a polythene cover to prevent moisture entry. This increases the cost of coffee erries drying
• quality degradation as a result of moisture entry, dirt, elements of nature, and other contaminants
• it requires lots of space because the beds cannot be designed in a storeyed manner
• none uniformity of drying because it is turned over by hand on the raised drying beds

Open drying of coffee cherries in a coffee factory in western Kenya

The key advantage of open sun drying of coffee is that it is cheap, and has zero CO2 emissions

The coffee is dried from 60% to 10% – 11% moisture level. There are six stages in cofee drying

1) Skin drying. Moisture 55-45%.
2) White Stage drying. Moisture 44-33%.
3) Soft Black stage. Moisture 32-22%.
4) Medium Black Stage. Moisture 21-16%
5) Hard Black Stage. Moisture 15-12%
6) Fully dry coffee and conditioning. 11-10%

Coffee drying is a post-harvest handling process where the coffee quality is preserved instead of improving it. Different temperature limits are allowed for different coffee processing methods. Moisture level are checked to prevent moulding on the drying coffee

Solar dryers for coffee in Kenya by Grekkon Limited provide a low cost, efficient, zero CO2 emissions, and a clean way to dry cofee cherry. The use of solar dryers mitigates against the challenges faced under open sun drying.

How does a solar dryer for coffee work?

1. Air in the dryer in contact with the coffee is heated through solar radiation

2. Moisture in the coffee beans rises and is expelled through a ventilation

The temperature in the coffee solar dryer is on or about double that of the ambient temperature

Benefts of a solar dryer for coffee

• the coffee beans are not tuned over manually to achieve eveness of drying. This cuts out the huge labor cost coffee factories incur during coffee drying. Eveness of drying is well achieved as hot air dries every bean uniformly
• there is no external mositure entry especially from rain. This removes any occurence of moulding or mildew
• coffee dries at half the time or less that it would take under direct sun drying. This reduced drying time saves on operational costs
• there are no external contaminants

The exterior of a solar dryer built in a coffee factory by Grekkon Limited

• the polythene paper cover used has UV block treatment which preserves the quality of the coffee bean. It also has anti-drip attributes, so that dew does not form on it, then drop on the coffee
• space is eficiently used because the drying racks are stacked up over each other, unlike in open sun drying where each coffee cherry must make contact with the sun’s rays to dry
• in areas where coffee theft in factories is rampant, the solar dryer can be locked to prevent entry. This is not possible under open sun drying
• drying goes on even in hazy, cloudy or rainy conditions. Coffee is thus dried anytime of the year, creating drying efficiencies for the coffee factory

Demerits of a dryer for coffee

• it is expensive to isntall
• the polythene cover has to be changed every 3 -4 years when the UV block treatment has worn off
• it is uncomfortable to work in during the day as the internal temperature is high
• where care is not taken, over-drying of coffee may happen, which reduces its quality and its subsequent market price. A moisturemeter should always be used in the drying process to prevent this
• it requires maintainance, such as replacing the UV block treated polythene sheet every 3 years, when the UV block treatment degrades

A coffee solar dryer working principle

A conventional coffee solar dryer can be enhanced with solar module powered extraction, and exhaust fans, which converts it to a hybrid coffee solar dryer. This will further improve on the drying time as moisture is extracted faster. However, due to the large size of the unit, it is an expensive undertaking. It is largely used in smaller fish, herbs, spices,vegetable and fruit solar dryers

How to install solar dryers for coffee

• create raised tables from timber or galvanised steel not more than 1M in width. The length is as much as can be done. These tables can be storeyed upto 3 levels with vertical gaps of 0.75M – 1M between the levels. The horizontal distance from a table to another is 0.5M
• lay a food grade wire mesh over the tables to hold the coffee. A shade net or insect net can be used. The reason a perforated membrane is laid is to allow for free drying air movement on the beans
• construct the galvanised steel framework over these tables to amaximum mid height of 5M
• lay the greenhouse polythene paper over the steel frame
• place an insect net in the air entry and exit points. An insect net prevents entry of insect pests

A 2 level table bed coffee dryer by Grekkon Limited in Kagumoini area, Nyeri county

Grekkon Limited provides training on proper coffee drying in a solar dryer, and also on the maintainance and managemnt of the solar drying unit after installation to coffee societies in Kenya
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