The ideal greenhouse and how to take care of it

Many farmers are turning to greenhouses in search of higher yields and some are constructing the structures themselves to save costs.

But what consists of a good greenhouse and how does one take care of it. Leopold Obi spoke to Taita Ngetich, the director of Nairobi-based Illuminum Greenhouses Kenya

What features should a good greenhouse have?

It should have strong support structures, which can be wooden or metallic. Then the ultra-violet treated polythene should be 200 microns.

The greenhouse should also have an entry porch and insect net to keep pests away and also provide proper ventilation inside the greenhouse.

The greenhouse must also have an irrigation system — preferably the drip kit. It is not only efficient in terms of water usage but also reduces the risk of spreading diseases.

Not far from the structure one should have a water tank for irrigation and or fertigation purposes.

Before you construct the greenhouse, do a site assessment to ensure all factors that can affect the structure are taken into account.

They include the intensity of the wind, land topology and source of the water and its availability.
Normally, the greenhouse polythene and insect net are a bit delicate. Therefore, keep sharp items away from the two. However, any tears can easily be repaired.

The drip kits are also susceptible to clogging, therefore, a good kit should come with a filter which is usually located just after the water tank as the water is flowing into the greenhouse.

The filter minimises entry of large particles into the drip system. It should be cleaned regularly to ensure that it works well.

It’s advisable to flush the entire drip kit using special chemicals to eliminate any unwanted agents inside the drip kit that may cause clogging.

How effective are greenhouses in controlling the spread of pests and diseases on the farm?

The structure comes with a net, which prevents entry of pests inside the greenhouse. Besides that, the entry porch should come with a footbath section which ensures that the visitors or farm workers sanitise their feet before and after leaving the structure. Secondly, a two-door system minimises pests and unwanted agents.

Acquisition of greenhouses remains a big challenge to smallholder farmers due to high costs. Why are prices still high despite many players coming in the industry?

Some of the materials needed for the construction of the structures are sourced from foreign countries. As much as the Kenyan manufacturers can produce the said materials, the quality still remains a challenge.

The high costs definitely translate to high retail prices of the greenhouses. However, use of wood to construct the structure helps to bring down the cost.

Most firms selling greenhouses have constant prices, but the contracts include some clauses which lead to price fluctuations. The contracts also come with certain crops farmers choose from.

Any advice on the kind of crops that a farmer can effectively cultivate in a greenhouse for peak harvests?

One can grow just about anything in a greenhouse, but it all starts with market research to get a feel of the prices for various products and to know where to sell.

If someone wants to buy a greenhouse (standard measure), how much should they have?

A standard greenhouse is 8m by 15m and the cost averages Sh164,000.

Some farmers are opting to make their own greenhouses, how good or bad is this practice?

The advantage is that the farmer saves on costs but the demerit is that one may end up using substandard materials due to lack of expertise.

Some farmers end up with a weak structure that may not support good growth of crops and would not last for long. The thing is always work with experts.