As a greenhouse company in Kenya, our types of greenhouses in Kenya are based on 5 main categories. In temperate climates, greenhouses produce food in the winter. They have a heating system to do this. Greenhouses in tropical climates such as Kenya have no heating, and produce all year round. They have a UV treated polythene cover, not glass or fiber glass. In the ventilated sections, they have white colored low or high density insect nets. The choice of white is because it reflects much light which deters insect entry. It also reflects off heat
Types of greenhouses in Kenya; categorization
1. Construction material
1.1. Galvanised steel greenhouses
The steel bars used in greenhouse construction in Kenya are of various sizes depending on their position in the structure. Thicker and stronger steel bars are on the edges as anchors. The lighter steel gauge is on the roof, and also acts as the internal crop support system. The choice of thickness of the steel bars adopted depends on the greenhouse location. In windy locations, the steel bars are deliberately stronger than in calm areas.
Food grade aluminum or zinc is what Grekkon Limited uses to galvanise these steel frames to keep them from rust. All vertically placed steel bars that are in contact with the ground have a concrete base. This strengthens the structure, and holds it in place during strong wind, or a storm.
1.2. Wooden greenhouses
Treated timber greenhouses are cheaper than galvanized steel greenhouses. They have a shorter lifespan, because wood degrades faster than galvanized steel.
Growers are not to treat the timber with used motor oil. This is because it will contaminate food crops.
2. By activity
2.1. Crop production
Galvanised steel or wooden greenhouses are for food crop production, and ornamentals. These structures have planting beds to ensure proper drainage, and irrigation is by drip systems.
2.2. Seedling production
The have 1meter high tables for seedling trays placement. On the roof, is a system of misters or foggers to humidify. This is necessary because high humidity id necessary for root propagation, and seedling development. They are for propagation of; vegetable, herb, fruit, cereal, spice, forestry, and ornamental crops.
2.3. Fish rearing
Fingering production, and fish rearing in greenhouses is a growing practice amongst Kenyan farmers. This commercial venture is due to the growing demand for fish and fish products locally, and internationally. They are shorter in height than crop production greenhouses, and are warmer.
3. The design adopted
3.1 Vented type greenhouses
They have an opening on the roof, and are taller in height. This opening, and additional height allows for more airflow in the structure, creating a higher cooling effect. These are for very hot- where average daily temperatures are beyond 30 degrees Celsius. This is for the mid to low altitude locations
3.2. Tunnel type greenhouses
Their roof is continuous, and have only the side ventilation. They are also shorter in height. Constructed in the highlands, or cool locations. Daily average temperatures here do not exceed 30 degrees Celsius
4. Crop type
4.1. With a crop support system. This consists of a metallic crop support structure made of vertical metal bars in the greenhouse. These metal bars are arranged in rows with a spacing of 3M between one row to the other. Steel wires running vertically, and horizontally between these metal bars train the crop and keep it in position. This crop support structure is for tall indeterminate crops such as tomato, cucumber, and capsicums
4.2. Without a crop support system. This is for short crops that do not need training. They are; strawberry, leafy vegetables, most ornamentals, herbs and spices
5. Unit positioning
5.1. Stand alone greenhouses do not exceed 8M in width
5.2. Greenhouses from 16M in width are designed as co-joined unit