What is Greenhouse?
A greenhouse is a structure where plants and crops grow in a controlled environment . The structure is generally made of glass or polythene covers depending on the availability and cost of the material. These structures range in size from small sheds to big buildings. Greenhouse farming technology started in Italy 13th century. Then spreading to Netherland and England. In Kenya, greenhouse farming started in the 1980s.
Types of Crops Grown in a Greenhouse
Various crops grown in a greenhouse include cucumbers, flowers, tomatoes, capsicum. Also, cultivation of bamboo, herbs, ginseng, high-end mushrooms, onions, garlic, and shallots is possible. Generally, the crop grown in it are of high value returns comparatively to its high cost of construction.
Advantages of Greenhouse Farming
- High production per unit area of land
- Easy control of pests and diseases.
- Prolonged production period.
- Efficient water utilization.
- Low cost of labour involved in spraying, weeding and watering.
- High quality of crop production.
- Timely crop production.
- Matching to high market demand.
- Huge saving on crop protection chemicals.
- Less exposure to chemical toxins associated with its application.
Challenges of Greenhouse Farming.
- The high initial cost of investment.
- High level of management skill required.
- not easy to control humidity and temperature under extreme weather conditions.
- Need for clean water all around the year for crops.
- Loss in the fertility of soil if the same crop repeated over time.
- Insects and pathogens attack as the conditions are suitable for their growth.
Usually, greenhouse farming was affordable for big and medium scale farmers. This was due to the high cost of construction. But low-cost greenhouses have come up as a revolution to suit the small scale farmers. The structure is made from the locally available material. These materials are cost-effective. They, therefore, can enjoy the fruits of technology.
Difference Between Metal Greenhouse and Wooden(affordable) Greenhouse
The difference between a metal greenhouse and a wooden greenhouse are as follows.
Firstly, metal green is doom shape. Whereas the wooden one is not doom shape. Secondly, in a metal greenhouse, you have to waste a lot of space. This is because it is shorter. Most of the tomatoes in a greenhouse can grow up to 10 feet tall. So you require a little bit of raised greenhouse that will be able to accommodate them. third, in a metal greenhouse, you require to put more poles. This is done so that you can raise trellises for your tomatoes. In this wooden greenhouse, you do not put extra poles because you already have trails of barbed wire that will support your trellises.
It is very easy for an internal environment of a greenhouse to modulate it. In this case, if you look at this greenhouse. It has 70 per cent insect netting. That can be able to change the environment inside. It can also stay for a longer period. This green can go up to 10 years. With that small investment, you will the cost of investment and profits recover within 10 years.
Construction of Affordable and Cheap Greenhouse
The greenhouse construction is in two stages. The first stage involves setting up the structure. While the other stage involves green cover net and net installation.
Factors to be Considered Before Construction of a Greenhouse
Now to construct a low-cost greenhouse, you need be able to do the demarcation of the site. Where you will be able to put up your structure There are various factors to be put up into consideration when you do the site selection. This is done to have a definite and well structure of the greenhouse. One of the factors to be considered is the terrain and topography of the structure. It has to be simple and well-drained topography. It will allow the water to drain systematically without any mechanical method.
Also, we need to look at the direction of the wind. Where does the wind come from? Because if you just construct without looking at the direction of the wind, your greenhouse structure will blow out. By the end of the day, you will encounter any extra course to put up another greenhouse structure. The factor we need to look in is the type of soil where you are putting out your structure.
Type of soil
We have diff range of soil. But we actually require well-drained, lonely and fattening soil. The other aspect you need to look is the security. The structure needs to be as close as possible to the homestead. So that you can be able to monitor all the farm activities during day time as well as at night.
Crops for Cultivation
You also need to consider the type of crop grown on the particular place initially. And the type of crop you want to grow in your greenhouse. For instance, if you have been growing potatoes, and you need a put up a greenhouse that you need to grow tomatoes, it will be advisable to put on a different site because you will not be able to put a green where we had a similar type of crop is grown from generation to generation.
Water Availability and Storage
The other aspect that you have to consider is that you have a regular source of water supply. The supply should be sustainable because we need to have a tank where you can store water. Also, you require clean water that will improve your production of crops.
Step by Step Method of Constructing a low-cost Greenhouse
Post selection and hole size
The standard size of a greenhouse is 15 meter by 8 meters. to construct it you need posts. the length of the post should be 13 feet. We have the 18 feet post known as fly post. They run parallel to structure. Kingpost is present in the middle of the structure. They hold the structure in position. You have to dig a hole that is three feet deep. This hole will accommodate the 13 feet post. The 13 feet post will go three feet underneath. remaining 10 feet shall remain with you as your king post. On the 18 feet post, 3 feet will go in the hole. The remaining 3 feet will remain above ground as the fly post.
Used up oil and polythene for wooden posts
Used up oil layer on posts will prevent your wooden material from infestation from insects and rotting. Wrapping polythene around the post when you fixing them in their holes. This will prevent them from rotting as the structure will last for a minimum of ten years.
Straps, nails and tape measure for measurement and reinforcement
You also need some straps. You need them to reinforce your greenhouse structure. Nails and tape measure are must for construction.
Installation of drip lines is necessary. This is to ensure a regular supply of water. Their installation is done once the construction of the greenhouse is over.
Disinfectants are needed at the entrance of the greenhouse. When you enter the greenhouse, disinfectants will make you are free of pathogens or and diseases.
When undertaking greenhouse construction, beds designing and bed raising practices are necessary. There two basic reasons why you need to undertake bed construction before greenhouse construction is completed. One, there is a lot of mechanical work underway that you cannot do when you are covering your greenhouse with cover. Two, you require to bring in manure and this can only be done before covering your greenhouse. Because of the movement of manure in the greenhouse, and also because of the movement of the subsoil in the greenhouse. You need to do this before completion of greenhouse covering.
The bed is 75 cm in width. The distance from one bed to another that is 50 cm. The width of the working path is 50 cm. This greenhouse of size 8 meter by 15mstre can accommodate 6 beds that are 14.5 meters in length and 75 cm in width. These beds are made by mixing topsoil and some manure. You require 10 wheelbarrows of manure for every bed. You also require some charcoal. Charcoal helps in carbonation. These beds require to be raised up from ground level. These raised up beds enable free movement and easier transplanting of tomatoes and other crops.
We need to install barbed wire. The barbed wire runs parallel to beds. This wire help to do what we call trellises or support the tomato when they are in production. This is the main reason for installing barbed wire in the green. The wire also helps the string to remain in position so that they do not move. If we put an ordinary wire, the wire tends to move and the tomato tends to break.
We have to put insect netting around the greenhouse. We have a netting of width 1 meter that will cover 70 per of the structure. The net will enable the house to have a clear circulation of air. It will also restrict the entry of insects in the greenhouse. This will regulate the temperature in the structure. Without the netting, the plants may scorch. That is why we have to install netting.
U.V treated 200 micron cover
Then we need to start with the installation of a 200-micron cover. It is a transparent 200-micron green cover. This is a UV treated cover. It will only allow a definite amount of sun rays that will penetrate through. This will allow the environment in the green to be conducive for the tomatoes to grow well. If we do not use it, tomatoes will end up scorching and will eventually affect the physiological growth of tomatoes.
So its imperative to chose the right design and right material to construct a greenhouse. We advise choosing 200-micron U.V treated green covers that you get from a credible and reliable source near you.