Tomatoes are a major vegetable grown in Uganda, and as Farmiket, we look forward to giving extension service support to our farmers to successfully grow them.
Planting season in Uganda of tomatoes is dependent on the rainy season, but with the availability of irrigation water, tomatoes can be grown all year around. Tomatoes take about 60 days to more than 100 days depending on the cultivar. Below is a detailed but also simplified step-by-step procedure to successfully grow tomatoes.
- CULTIVAR SELECTION
- There are many cultivars on market with wide range of flavors as well as colors, sizes, growing length, adaptability to diseases or weather. Tomatoes do need vigilant care, as the crop is susceptible to pests and diseases. To avoid problems, choose disease-resistant cultivars whenever possible.
- NURSERY BED PREPARATION
- Sow seeds a 2 cm deep in small trays or on a raised seed bed for 6 to 8 weeks.
- Harden off the seedlings for a week before transplanting them in the ground. Remove the shade for a few hours on the first day. Gradually increase this time each day in direct sunlight.
- Select a site with full sun and, ideally, a space where tomatoes (and members of their family, especially eggplants, peppers, and potatoes) have not grown in the previous couple of years.
- When planting seedlings, pinch off a few of the lower leaves. Place each root ball deep enough such that the bottom leaves are just above the surface of the soil. Roots will grow all along the plant’s stem underground.
- Plant seedlings 2 to 3 feet (60cm) apart. Crowded plants will not get sufficient sun and the fruit may not ripen.
- Water well to reduce shock to the roots.
- When you transplant tomatoes, add a handful of organic tomato fertilizer or bone meal (a good source of phosphorus) to the planting hole. Do NOT apply high nitrogen fertilizers such as those recommended for lawns, as this will promote luxurious foliage but can delay flowering and fruiting.
- Water in the early morning so that plants have sufficient moisture to make it through a hot day.
- Water generously the first few days that the tomato seedlings or transplants are in the ground. Deep watering encourages a strong root system.
- Avoid overhead watering and afternoon watering. Water at the base/soil level of a plant to avoid splashing water on the leaves (which invites disease). Drip irrigation is the best suited.
- Mulch 5 weeks after transplanting to retain moisture, keep soil from splashing the lower leaves, and control weeds. Apply 2 to 4 inches of organic mulch such as straw, hay, or bark chips.
- You should have already worked compost into the soil before planting and added some bonemeal (phosphorous) to the planting hole when transplanting.
- Side-dress plants, applying liquid seaweed or fish emulsion or an organic fertilizer every 2 weeks, starting when tomatoes are about 1 inch in diameter.
- Note: Avoid fast-release fertilizers and avoid high-nitrogen fertilizers. As stated, too much nitrogen will result in lush foliage but few flowers and little or no fruit.
Pruning, pinching, staking
- If growing vining tomatoes, pinch off suckers (new, tiny stems and leaves between branches and the main stem). This aids air circulation and allows more sunlight into the middle of the plant.
- Gently tie the stems to stakes with rags, nylon stockings, twine, or soft string.
- As a plant grows, trim the lower leaves from the bottom few inches of the stem.
Pests and disease control
- When it comes to tomato diseases and other problems, most of the work is in prevention. Here are some tips to avoid tomato diseases:
- Rotate crops at least every year in the same spot. Avoid planting Solanaceous family members as well (potato, pepper, and eggplant).
- Ensure well-draining soil. Always mix in compost or organic matter.
- Water consistently! Do not overwater if you forget nor underwater.
- Destroy infected plants. Do NOT put in a compost pile.
- Solarize the soil. If the problem is really bad, you can treat your soil by covering it with plastic during the hottest part of the summer for 6 to 8 weeks; the sun will destroy the bacteria.
- Monitor tomato plants daily, checking under leaves, checking fruit, and checking near the soil.
- Apply organic pesticides/horticultural oils or sprays diluted in water. Neem oil sprays block an insect’s air holes.
Tomato Diseases and Problems
- Blossom-End Rot causes the bottom side of the tomato to develop dark, sunken spots, due to a calcium imbalance.
- Early Blight is a fungal disease that causes leaves to drop; it’s common after rainfall or in humidity. It starts with dark, concentric spots (brown to black), about ½-inch in diameter on the lower leaves and stems. If you catch it early and destroy infected leaves, your plant may survive.
- Late Blight is a fungal disease that causes grey, moldy spots on leaves and fruit which later turn brown. The disease is spread and supported by persistent damp weather.
- Mosaic Virus creates distorted leaves and causes young growth to be narrow and twisted, and the leaves become mottled with yellow. Unfortunately, infected plants should be destroyed (but don’t put them in your compost pile).
- Fusarium Wilt starts with yellowing and wilting on one side of the plant and moves up the plant as the fungus spreads. Unfortunately, once this disease strikes, the plant needs to be destroyed.
- Powdery Mildew is a fungal disease which leaves white spots or a dusting of white on the leaves. It can be managed. See the link to learn more.
- HOW TO HARVEST TOMATOES
- Leave tomatoes on the vine as long as possible.
- Harvest tomatoes when they are firm and very red in color, regardless of size, with perhaps some yellow remaining around the stem.