Hanks Saisai
Tomatoes, scientifically known as Lycopersicon esculentum, are grown during spring and summer (September to the end of April) for their fleshy fruits that are rich in taste and Vitamin C.
Tomatoes are a very popular commodity used in everyday home recipes and as a complimentary ingredient in most vegetable salad dishes. Tomatoes are either determinant or indeterminant plants depending on which cultivar you choose to grow. Determinant varieties grow into a bush while indeterminate tomatoes grow over two metres in height and yield about 40 to 70 fruits per plant.
Soil preparation and sowing of tomato seeds.
Tomatoes grow in most soil types, however, to achieve optimum yield good soil preparation should be done two to three weeks before planting.
Simple but crucial steps to growing tomatoes are:
• Tilling the soil to a depth of 20 to 30cm and incorporating cattle manure before planting may prove essential during the growing season.
• Plant in seed trays containing Hygromix, which is a suitable growth medium for most vegetable seeds at a depth of at least one to two cm.
• Careful irrigation using a watering can in a nursery is recommended and after 10 to 14 days, germination and emergence of the seedlings should occur.
• Transplanting can be done when the seedlings are about three weeks old and are about 12 to 15cm tall.
• The seedlings can be grown using the following spacing recommendation; Spacing between the rows must at least be 40cm and spacing within a row can at least be 20cm from one tomato to the next tomato growing in the same row.
Caring for the tomatoes
Once the seedlings are transplanted, it is essential for farmers to support the growing tomatoes by staking an act of placing a stick or any other support structure on which the tomatoes are tied. Staking prevents the plant from growing along the ground keeps tomato fruits off the ground and reduces the risk of diseases.
Whilst it is important to water the tomato plants, it is advisable to avoid sprinkler irrigation when it is very hot as water on the leaves may result in the spread of diseases. Watering can be done daily, but careful consideration of soil texture may be of great importance.
Sandy soils drain faster, thus one is encouraged to irrigate at least once a day. Weeding is a must for a tomato grower, this must be done by hand whereby weeds are pulled out of the seedbeds. Pruning on certain cultivars of tomatoes is recommended to increase yield potential.
Additionally, a good fertilisation programme is necessary for successful tomatoes. One can opt to use fertigation whereby every third week NPK 2:3:2 (37%), which is water soluble, is incorporated into the irrigation system to supply the essential elements towards the flowering stage.
In addition, farmers are encouraged to use Potassium rich fertilisers such as Potassium sulphate via water-soluble mixtures. Scouting throughout the growing season is a major must for tomato growers, as tomatoes are highly susceptible to diseases such as early or late blight and pests such as Leaf miner and Tuta absoluta.
Depending on your location and the prevalence of diseases and pests, a careful spraying program is a necessity and must be done at least once a month.
Harvesting is expected at 90 to 110 days after transplanting and this can be done by hand, whereby the farmer carefully breaks the fruits off the plant. The fruits must then be washed and stored in a cool and dry place before being transported to the market. While transporting them to the respective markets, it is essential to avoid exposing them to direct sunlight as it may negatively affect the shelf life of the fruits.
A good yield of tomatoes is subject to good soil preparation and fertilisation of the soil in which crops are to be grown. Importantly, a good investment in high quality seeds of the right variety (determinant or indeterminant) must be made, and always ensure that you follow the instructions on sowing season, sowing depth, and careful irrigation which are essential for a good seedling establishment.
-Hanks Saisai is Agribank’s technical advisor for crops and poultry