Kenya is the lead exporter of rose cut flowers to the European Union (EU) with a market share of 38%. Approximately 50% of exported flowers are sold through the Dutch Auctions, although direct sales are growing. In the United Kingdom, supermarkets are the main outlets. Over 25% of exported flowers are delivered directly to these multiples, providing an opportunity for value addition at source through sleeving, labelling and bouquet production. Kenya flowers are sold in more than 60 countries.
The main production areas of roses and other cutflowers are around Lake Naivasha, Mt. Kenya, Nairobi, Thika, Kiambu, Athi River, Kitale, Nakuru, Kericho, Nyandarua, Trans Nzoia, Uasin Gishu and Eastern Kenya.
Varieties
Include Red one, Fusciana, Inka, Moon walk, Sweet unique, Athena, Star fish, Queen Africa, Top sun, Avanti, Amani, Tropical amazon, Oracle, Super Akito among others
Growth requirements
Temperature is the most important growth aspect; the crop grows in regions with 20-28 degrees centigrade. Most growers use hydroponic systems in order to conserve water and to increase better nutrient utilization. If grown on soil then pH should range from 4.5-5.6
Planting procedure (on hydroponics)
- Make beds 60-90cm wide, lay out hydroponic trench systems (mapal troughs) and drip system
- Add pumice, course particles at the base followed by finer particles
- Flush the media to wash off salts in order to make it more inert
- Load drench the media with phosphoric acid to regulate ph.
- Add bio-gear, an organic manure containing vital elements for plants use (N=1.2, Mg=0.3, Ca=21.4, P205 =1.1, K20=8.0
- Add compost manure, improves water holding capacity
- Spacing depend on rose variety, growing habit, growers’ preference and drippers spacing
Crop management
Bending- First bedding is done 5-8 weeks after planting depending on foliage. Its done 2-5cm from the ground to encourage shooting of healthy and strong stems.
Re-bending- Done after the first bending for the emerging weak stems. This increase surface area for photosynthesis thus resulting to rapid growth of the healthy and strong stems.
Gapping- Done to replace plants that fail to establish, this helps to ensure that the intended plant population is achieved which reflect to yield target.
De-suckering– Refer to the removal of extra buds that grow on a single stem, this ensures production of healthy flower heads and reduces competition for growth resources
Torch removal– involves falling flowers that are fully open as they are not harvested for sale and may harbor pests such as thrips. It also encourages development of more shoots
Knocking down– Involves removal of unwanted buds during early stages of growth. It reduces nutrient competition with the desired shoots thus increase the size of flower head and improve quality.
Nipping– involves removal of bended shoot tips (forming flower buds) which enhance re-mobilization in the plant
Pinching– done to delay or increase production, should be done at the first or apical leaflets. Hard pinching (when more than pea size) and soft pinching when flower head is pea size
Plant nutrition
Plant feeding is the key to realize good harvest in flower production, most fertilizers used are mono-fertilizers with specific crop nutrient which are mixed in separate tanks as follows:
| TANK A
(NITRATES) |
TANK B
(SULPHATES& PHOSPHATES) |
TANK C
(ACIDS) |
| Calcium nitrate | Mono-ammonium sulphate | Phosphoric acid (15kg) |
| Iron chelate | Chelated copper | Nitric acid (30kgs) |
| Potassium nitrate | Zinc chelate | |
| Sodium molybdate | ||
| Borax | ||
| Ammonium sulphate | ||
| Magnesium sulphate | ||
| Potassium sulphate | ||
| Chelated manganese | ||
| Copper sulphate |
NB: The acid ratio should be 1:2, phosphoric acid to nitric acid ratio respectively.Acids are very explosive especially nitric acid. When mixing the acids, half fill the tank with water and then add the acids each at a time.
Pest control
IPM, integrated pest management is involved in order to meet GLOBALGAP and export guidelines
Thrips– Controlled using biological agents eg Hypo apsis, Amblyseius cucumeris, Beauvitech (Beauveria bassiana) and Orius pirate bugs. Chemicals such as duduthrin, aceta, prove, Taurus, ecoteck can be used sparingly. Entomopathogenic fungi such as Beauvitech(Beauveria bassiana) and Lecatech(Lecanicilium lecanii) can be used to control larvae stages. To monitor thrips use blue sticky traps
Mealy Bugs– Spray with applaud or knockbectin
Nematodes– Use Entomopathogenic nematodes,Nematechs (steinernema feltiae)
White flies – Use entomopathogenic fungi such as Lecatech (Lecanicilium lecanii) or Beauvitech (Beauvaria bassiana). To monitor the white flies, use the yellow traps. Chemical control involve spraying applaud and toepol
Caterpillars– Spray using duduthrin, merit, Teppeki or nimbecidin
Red spider mite– Use biological agents such as Amblyseius cucumeris, Amblyseius califonicus and hypo apsis mites. Avoid dusty conditions by hosing water on the crop and on the ground. Chemicals such as floramite and mite kills can be used when population is high.
Scale insects–Spray using karate, engeo or match
Aphids – Spray using karate, engeo or match. Biological agents eg aphidius, a parasitoid can be used to control the pest
Disease control
Downy mildew- Spray with Ridomil gold, Brilliant or Top Net 500 SC
Powdery mildew– Spray with powerdiff, preserve, trustmaste, flint, splendor, microthiol and mennoflarades
Crown gall – Caused by agrobacterium tumefaciens. No known chemical known for its treatment but old engine oil has been used by some flower growers (by making hole in the gall and putting oil inside), the gall dries with time. Always disinfect harvesting tools to avoid disease spread.
Fusarium wilt, Rhizoctonia, sclerotinia and Pythium-Can be controlled using Mytech (Paecilomyces linacinus) and other soil borne diseases.
Harvesting
Disinfect harvesting tools using chlorine solution before cutting the stems to avoid disease spread such as crown gall. For newly planted crop, harvesting starts in the 52nd day after planting. Cut stems at a height of 1cm above two leaf nodes above the cut point. Harvest stems that are 43cm, 53cm and 63cm and above, dependent on market orders. Remove and dispose off week stems from the crop stand. Care should be taken to avoid bruising the flower heads, bruised flowers are unmarketable. Wrap the flower heads using nets to avoid bruising during transportation to cold stores or pack-house.
Post-harvest handling
Harvested stems should be dipped in post-harvest solution and taken to pre-cooling facility. Stems of same length should be put in one bucket containing the post- harvest solution to ease sorting in the pack-house.
Quality control check– starts in the field, post-harvest solution must be of the required standard to ensure flower quality is maintained all along the chain. At cold store entrance, the quality controller should sample and inspect the stems against pests and diseases, score the disease and pest severity and write a report to production manager to execute the right measures.
Sorting and grading- Done in the flower pack-house, it involves sorting flowers in terms of stem length. All stems that are broken are removed and disposed together with diseased ones, those with stem botrytis or botrytis of the flower head.
Bunching: Bunched according to stem size, each bunch may contain 5, 10 or 12 stems depending on the customer order. Bunch may have mixed varieties as per customer demand, mostly for the mixed ones they contain fillers.
Sleeving and packing: Bunched stems are sleeved using clear funnel shaped polythene sleeves and packed in cartoons ready for transportation.
Transportation: Roses are very sensitive to withering, cold chain should be maintained all along. Transporting vehicles should have cold facilities to ensure the flowers reach customers in desired quality, this also helps in achievement of the pre-tested vase-life.