Greenhouse can (is operating) operate perfectly without power and the climate condition will still be controlled for optimum yield. We don't need any power to operate greenhouse optimally instead we need water to function optimally which most time is supplied through borehole.
To control the climate condition within the greenhouse without power, play with the followings
1. Height of the greenhouse
2. The orientation of the greenhouse
3. The cover or shade nets
4. The colour of the shade nets
5. Placement of the shade nets
6. Material for mulching
7. The colour of the materials for mulching
8. Lastly, the type of crops you are growing.
9 The materials for the construction of the greenhouse.
Apart from sinking a borehole that will require electricity to pump water into the surface irrigation tanks, your drip irrigation tanks should be gravity-fed.
Once the above is taken care of, the expected yield of tomatoes is stated below
250 tons per Ha
25000 plants per Ha
Each plant does 10kgs...minimum in Green houses (GH).
Top grade GH varieties like Anna F1 is capable of over 30kgs per plant.
Dizengoff's Eva F1 is able to do 20+ kgs at 1500 altitude.
From experience and understanding, the height of our greenhouse in Nigeria because of the weather must not be less than 6m excluding the table section
And if the borehole is drilled through NACL salt layers then point 8 is pertinent because some crops perform poorly in saline salts.
If you are considering drip irrigation then the following must be taking into consideration.
1. You cannot irrigate by volume because each drip cone does varied volume
2. You cannot have uniform. Flow in basins and hills alike
3. You cannot control drip blockage because you've no high pressure provisions to dislodge debris from the drip labyrinth.
4. You lack services of head control hydronic pressure valves which are vital inputs in drip irrigation.
The general advice is, as you advance, go into conventional drip irrigation systems done by other farming communities.
We did it in 2013-2016 on a 300 acre farm in Kenya with Syngenta seed farm in Naivasha Kenya, We have also done Eva F1 and got its full 35kgs on a Netafim Co farm in Israel. Our climate in Nigeria is very similar to that of Israel.
It is possible in Nigeria too. Move to an altitude of 1000-1500 and put up a Greenhouse there.
Use river water for irrigation flowing through a conventional filtration system and install a good drip irrigation with availability of all Fertilizers recommended for that crop.
Apart from the altitude of 1000-1500 Height of Greenhouse.
What matters most are:-
1. Feeding menu
2. Type of growing media
3. Type of water
4. Source of seed and variety
5. Prevailing environmental conditions dictated by altitude
6. Cultural practices and technical knowledge of the grower. Etc,etc.
Altitude controls temperature,relative humidity,winds that make rain, air pressure, at times soil depth and profile,soil type and texture,etc. All these are factors that impact on crop vitality.
The most important attribute of altitude is temperature.
Tomatoes do well with optimal temp of 35 degrees Celsius day time and 20 night time for fruit setting.
For height of the greenhouse the issue is air movement to reduce the effect of humidity which is to high imparts on transpiration and nutrient uptake. The height and side slopes must facilitate convection / air movement with a vent on top to allow the warm air escape
The average yield of an outdoor or determinate or also known as field tomato is about 6kgs/plant for whole season.The Green house one starts at 15kgs/plant.
You will be lucky to achieve 2.5 kg per plant in open field in the south. 15 Kg per plant in green house. If you can keep the indeterminate alive for 6 months is possible via hydroponics or bioponics.
Yields of up to 30-80 kg per plant is achievable in fully sealed greenhouses with all parameters right. Co2 levels etc. There is a cost issue and a correlation with your cost to market in this environment
A true feeding menu must leave a minimum growing media EC 0.9 for Tomatoes if on soil and 1.2 if on an artificial substrate, and should lead up to late vegetative stage,then shortly overtaken by P to induce flowering and finally K tops till stoppage of harvesting.
Ca and Mg all time remain in their rightful proportions and ratios.Micros remain increasing in relation to biomass volume. Max EC on soil is 1.8, on artificial substrate is 2.5
Its best practice to embrace seeds from worldwide multinationals like Syngenta,Nicky's,Monsanto,HC clause,Hazera genetics,etc.
We generally have 8 hours of daylight in Nigeria at desirable flux. The use of LED in Nigeria is not necessary as cloud cover is very minimal, butprolong hours of light will make the tomato restless there by producing more fruits...though this process can alter the physiological response of the plant.
Yes the world ''misbehave'' is also related to a lady who is just giving birth every year with no family planning control
If farmers see all these high tech mentioned here and work locally considering local realities, I am sure they will adopt these practices. We are tired of seed marketing companies and green house or tunnel house traders dropping numbers that stimulate.
They should get a farm as they have done in Ghana (demonstration farm or commercial farms )/and show us the numbers.
The money will follow.
By: Ochieng Barasa