Greenhouse tomato production
Green house production creates an ideal production environment that includes ideal relative humidity, temperature and light. These results in high yields, efficient water utilization, high fruit quality, prolonged production, shortened maturity period, low pest and disease incidences, reduced use of land to achieve the same results i.e. ratio of about 1:10, low labour input and timing of market.
Tomatoes are of two types, determine and indeterminate. Determinate types are short and do not require support while indeterminate types grow endlessly and require support. Indeterminate types are more preferred for greenhouse production.
Popular fresh market varieties include Money Maker, Marglobe, Marmande, Elgon Dume, and beauty. The varieties for processing include determinate type namely Roma V.F, Cal-J, Onyx and Monyala F1,and indeterminate, type namely Anna F1,Monset F1, Arlleta F1,Money Maker,Marglobe.
Seedlings are raised in the nursery. The nursery site should be chosen where potatoes, brinjals, peppers, and other solanaceous crops have not grown in the last three years due to the risk of crop infection by soil-borne diseases and pest infestations. The seeds should be raised in nursery beds, seed boxes or germination trays. The seeds should be drilled thinly in rows 20 cm apart and 1cm deep. The soils should be kept moist but not in water logged and the nursery shaded. The seedlings should be later thinned to 7cm in rows so as to ensure sturdy seedlings. Transplanting is done a month after germination. The seedlings are uprooted with a ball of soil at 4 to 6 leaves stage.
Soil should be well-prepared, thoroughly dug to 1.5 feet deep to loosen the soil. Apply one (1) wheelbarrow of manure per meter and mix well with the soil. The land should then be divided into beds of 1m wide, after which DAP/NPK fertilizers are applied to the surface of each bed by sprinkling sparingly at a rate of 100g/meter square.
There should be a chlorinated hand wash at the entrance of the greenhouse as well as a footbath.
Seedlings are planted at a spacing of (60×30) cm, (60×45) cm or (60×60) cm. Single stem are recommended for narrow spacing and double stem for wider spacing.
Seedlings are transplanted when pencil thick and approximately 15cm long. If taller, it is advisable to bend the seedling horizontal to the ground while transplanting. To encourage more root development, seedlings should be planted two centimeters deep.
Tomatoes are supported early as possible to avoid bending. This should be done when the crop is half a foot high. Plastic string is more recommended and should not be too tight to allow the plant space to expand and avoid injury to the stem. The string is twisted round the plant on a weekly basis, in the afternoon when the cells are flaccid and elastic to avoid breakage of the stem. In the morning, the cells are turgid and hence delicate to bend at that time.
- Desuckering- all suckers are removed by hand as soon as they appear, hence frequent ?surveys’ around the greenhouse are necessary.
- Defoliation – too many leaves increase the canopy cover which may result in high relative humidity hence more prone to diseases. Old leaves should be removed. Once the tomato fruits are formed, the leaves below this truss should be removed.
- Truss pruning- any leaves around the fruit cluster is removed immediately they appear.
Top dress with CAN or Urea, to enhance the vigour after the first harvesting. Trenches are made between rows and the fertilizer is applied, covered and irrigated. The bed should be aerated (shallow digging) from time to time to avoid compaction.
should be fitted with deep irrigation system and watering should be done in the morning and in the evening.
Harvesting starts at 10 weeks after transplanting and when tomatoes have about 10trusses and each truss with 7-8 fruits. a truss should appear after every 18cm.
Yield: From each tomato plant the expected yield is at least 20 kg after 8 months.
- a) Aluminum tunnels
|Size||NUMBER OF PLANTS||COST OF STRUCTURE||COST OF IRRIGATION SYSTEM|
- b) Wooden green houses
|SIZE||NO. OF PLANTS||COST OF STRUCTURE||COST OF IRRIGATION SYSTEM|
6 x 10m
EXAMPLES:GROSS MARGIN FOR A 240M2 ALUMINUM GREENHOUSE
|Item||Unit||Unit Cost||Total Cost|
|1.||Green house 30m x80 m wooden||1||208,700||208,700|
|Item||Unit||Unit Cost||Total Cost|
|2.||Pesticides (insecticides, fungicide)||7000||7000|
|3.||Growth hormone( flowering)||2000||2000|
|4.||Fertilizer DAP,CAN,Foliar Feed||25kg||5000||5000|
|1000 Tomato plants@20kgs||20000kg||20||400000|
|NB: Labour costs for management not included|