The appearance of the first tomato flowers marks a significant shift in the plant’s life cycle, transitioning from vegetative growth to reproduction. The plant begins dedicating resources toward fruit production, requiring a change in management strategies. Successful fruit development relies on specific adjustments to ensure the flowers set and mature. Attention to the plant’s environmental and physical needs during this stage directly correlates with the final yield.
Ensuring Successful Pollination
Tomato plants possess perfect flowers, containing both male and female reproductive organs necessary for self-pollination. However, the pollen is locked inside specialized anthers, requiring physical vibration to shake it loose onto the receptive stigma. This mechanism, known as buzz pollination, is naturally performed by insects like bumblebees generating high-frequency vibrations.
When growing tomatoes indoors, in calm environments, or during periods of low bee activity, manual intervention is required to replicate this vibration. A simple method is to gently tap or shake the flower cluster or stake mid-morning when the pollen is dry and viable. A more effective technique involves using an electric toothbrush; placing the vibrating back of the brush against the flower stem mimics the high-frequency buzz of a bee. Successful pollination occurs when daytime temperatures range between 70°F and 85°F and the air is not excessively humid, as temperature extremes can cause pollen to become sticky or non-viable.
Adjusting Nutrition and Water Inputs
The metabolic demands of a flowering plant require an adjustment to nutrient ratios compared to the vegetative stage. Once flowering begins, the plant benefits from a reduction in nitrogen (N) input, which primarily drives leaf and stem growth. Excessive nitrogen at this point can lead to a lush, bushy plant with poor fruit production.
The plant’s focus shifts to requiring higher levels of phosphorus (P) and potassium (K) to support flower development and fruit formation. Fertilizer formulas with a lower first number and higher second and third numbers, such as 5-10-10 or 6-8-12, are appropriate for this reproductive phase. Consistent and deep watering becomes significantly more important once flowers appear and fruit begins to set. Fluctuations between saturated and dry soil create major stress, which can interfere with nutrient transport and cause issues like flower abortion. Maintain a steady, even moisture level in the soil without allowing the plants to dry out or become waterlogged.
Managing Plant Structure for Better Yield
Physical management of the plant’s structure, particularly pruning, is essential and varies depending on the variety’s growth habit. Indeterminate varieties, which continue to grow and produce fruit until frost, benefit from the removal of “suckers.” Suckers are small shoots that emerge in the crotch between the main stem and a side branch. Pruning suckers redirects the plant’s energy into the main vine and existing fruit, improving air circulation.
Determinate varieties, often called “bush” tomatoes, grow to a predetermined height and ripen most of their fruit within a short period. For these types, suckers should be left intact, as they contribute to the limited overall fruit set, and pruning them can reduce the total yield. Later in the season, gardeners may choose to “top” indeterminate plants by removing the main growing tip. This action stops vertical growth and forces the plant to allocate remaining energy toward ripening existing fruit before the season ends.
Troubleshooting Common Flowering Issues
One frequent disappointment for gardeners is “blossom drop,” where flowers dry up and fall off without setting fruit. The primary causes are environmental stressors, with temperature extremes being the most common culprit. Tomato pollen becomes sterile when daytime temperatures consistently exceed 90°F or when nighttime temperatures fall below 55°F.
Other factors contributing to flower loss include poor pollination, high nitrogen fertilizer, and inconsistent watering practices. If the issue is heat, providing temporary shade during the hottest part of the day can offer relief. Blossom End Rot (BER) is a physiological disorder that appears as a dark, sunken spot on the bottom of the fruit. BER is a localized calcium deficiency in the fruit tissue, caused by the plant’s inability to transport sufficient calcium due to inconsistent soil moisture levels. Maintaining a stable water supply is the most effective solution for preventing both BER and watering-related blossom drop.