During the Naivasha Horticultural Fair in Kenya Green Farming presented the results of their projects on efficient and environmental friendly water and fertilizer management, and on the use of solar energy for electrical and thermal energy generation. Guest speakers, the CEO of the Kenyan Flower Council and a representative of Chase Bank, reflected upon current sector developments and the implications of the demonstrated technologies for the sector.

The Green Farming projects are co-operations between Dutch and Kenyan private sector and research partners, and are supported by the Dutch Ministry for International Trade and Development Cooperation. Extensive data sets have been recorded at the project sites that provide the Kenyan sector and Dutch partners with important technical and financial insights.

A comparative research between a hydroponic and soil cultivation system for rose was executed by the Jomo Kenyatta University for Agriculture and Technology (JKUAT), Wageningen UR and DLV Plant, together with partner Van den Berg Roses in Naivasha. The data from January 2013 up to June 2014 (1,5 yr) show the following advantages of the hydroponic system:
  • 56% less water use in the hydoponic system, due to re-use the drain water in the soil system
  • 44% lower fertilizer costs due to re-use of the fertilizer in the drain water
  • 41% more production in terms of number of stems
  • 65% more production in terms of weight
  • 20% more stems of the length sizes of 60, 70 and 80 centimetres
  • 43% higher turnover
The results thus show that with the hydroponic system impressive amounts of water can be saved, savings can be made in fertilizer use and that at the same time production results are much better than for roses grown in the soil. Based on these results the payback period for the additional investment costs to grow roses in hydroponics (calculated excluding costs for financing) is within the second year for a 6-ha production area.

The second project on the use of solar energy for electrical and thermal energy generation was presented by Mr. Martin Helmich of Hoogendoorn Growth Management. This project has been put into practice at Olij Roses in Naivasha earlier this year and aims at demonstrating a cost-effective use of solar energy that enables a farm to operate independent of local energy suppliers and produce in an environmental friendly way.

Solar panels are installed to produce electrical energy and solar heat collectors generate thermal energy. Part of the electrical energy that the solar panels produce is directly used by pumps and motors in the greenhouse. The excess electrical energy is stored in a battery-pack from which energy can be tapped during the night. Thermal energy is stored in a heat storage tank from which part of the farm can be heated during the night.

The project partners expect a reduction in energy costs up to 40% and - through the heating of the greenhouse- a greenhouse climate improvement and increased production and quality. Estimated payback time on the technologies for a 3-ha production area is:
  • <4 years for the total system; combining heat and power
  • 2,5 years for the solar collector system; heating only
  • 4 years for the PV panel system; power only
  • 6 years for the PV panel system with the batteries
For further information please download the seminar presentation containing the project results from the website and watch the "Solar-powered Greenhouse" project movie below:

For more information
Green Farming