Pollination and cluster pruning

Once a flower bud has been initiated, four additional processes must be completed before a healthy tomato fruit is set: the anthers must produce viable pollen; the anthers must release pollen to the stigma; the pollen grams must germinate on the stigma; and the pollen tubes must grow down the stigma, resulting in fertilization of the ovules in the ovary. Adverse temperature, light, and nutritional conditions can cause these processes to fail, resulting in poor fruit set and poor fruit quality Day air temperature undoubtedly plays an important role in fruit set, and once flowering starts, it should not fall below 18°C. Other potential causes of poor fruit set include excessive growth, poor light, incorrect nutrition, and any kind of crop stress. During late fall, winter, and early spring, flowers of most cultivars grow with a slightly different shape, making natural pollination difficult. This change in shape appears to be the result of low night-air temperature and is occasionally aggravated by high nitrogen availability To assist flower pollination, vibrate all flower clusters with open flowers at least every other day Use electric vibrators, known as electric bees, to vibrate flower clusters, preferably between 11 a.m. and 3 p.m., when flowers are moderately dry and pollen is shedding. As alternatives to the labor-intensive electric bee, the tapping of the strings supporting the plants and the use of coarse water sprays have been tried, but the results were not satisfactory Hormone sprays were also used when pollination failed, but the quality of the resulting fruit was not acceptable for North American markets. Lately, bumblebees have been used for tomato flower pollination, with reasonable success. The bees are already commercially available, and growers' experience with them in the past has been good. Problems of fruit quality related to inadequate pollination are invariably the result of poor and uneven seed set within the fruit, which is known to cause hollow, misshapen fruit.

Overbearing can sometimes become a problem. To prevent exhaustion of the plants and to improve fruit size, control the number of the flowers per cluster through the recently developed technique of cluster pruning. This is a powerful technique and therefore must be applied with great caution. Prune the first two clusters to three marketable fruits and later clusters to four fruits. However, the optimum number of fruits per cluster varies with the cultivar and even more with the growing conditions. Although, a limited number of fruits per cluster invariably results in premium-priced large fruit, there is always a risk that a grower, underestimating the potential of the crop or failing to forecast good weather, might decide to remove too many fruits and thus unnecessarily limit production. Cluster pruning is undoubtedly most useful in the hands of an experienced grower who can use it to maximize financial return. Obviously, fruit to be pruned must be removed as soon as it can be handled, before it is too large.

Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

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