Problems with pollinating tomato plants

Leafy growth on a tomato plant without flowers or fruit is usually caused by adverse environmental conditions, but diseases, such as, viral diseases can also affect flowering and fruit set. Tomato plants fail to produce fruit when pollination does not occur.

Symptoms and diagnosis
Tomatoes have both male and female parts in the same flower but sometimes pollination fails to occur. The result is that the plants may appear to be healthy, growing well, and flowering, but many or all of the blossoms drop from the plant failing to form fruit.

Plants grown outdoors are generally self-pollinating as long as there is a breeze or other mechanism for moving pollen from anthers to pistil.

Life cycle
Weather conditions are key factors in successful pollination. Daytime temperatures over 90 degrees F. and/or nighttime temperatures below 55 degrees F. will diminish pollination in tomatoes. High humidity creates sticky pollen which does not transfer well.

Integrated Management Strategies

1. Follow planting guidelines for your time zone. Tomatoes planted too early or too late are more likely to have pollination problems. Early and late varieties may be more fruitful if weather is an issue.
2. Hormone sprays. Use of a blossom set hormone may increase fruit production if the cause is cool, cloudy weather, but not if the temperatures are too high.
3. Provide good culture. Minimize stress on your plants with proper spacing, watering, and pest management.
4. Fertilize properly. Avoid excess nitrogen which will promote foliage growth at the expense of blossom formation.
5. Pollinate by hand.

Tomatoes, pollination, honeybees, and the like may not always go hand in hand. While tomato flowers are typically wind pollinated, and occasionally through bees, the lack of air movement or low insect numbers can inhibit the natural pollination process. In these situations, you may need to hand pollinate tomatoes to ensure pollination takes place so your tomato plants bear fruit. Let’s look at how to pollinate tomato plants.

Can a tomato plant pollinate by itself?
Many plants are self-fertilizing, or self-pollinating. Edible plants like fruit and vegetables with self-pollinating flowers are also referred to as self-fruitful. In other words, you can plant just one variety of the plant and still get a crop from it.

Tomatoes are self-pollinating, as flowers are equipped with both male and female parts. One tomato plant is capable of producing a crop of fruit on its own, without the need of planting another one.

Nonetheless, nature doesn't always cooperate. While wind normally moves the pollen around for these plants, when there is none or when other factors, such as high temperatures and excessive moisture or humidity occur, poor pollination may result.

Tomatoes, Pollination, Honeybees
Honeybees and bumble bees can be sufficient substitutes for moving pollen on tomato plants. While planting a myriad of bright-colored plants in and around the garden can entice these helpful pollinators, some people prefer to maintain nearby hives. This practice is dependent on your personal needs and preferences.

How to pollinate tomato plants by hand?
Another option is to pollinate tomatoes by hand. Not only is this easy but it can be quite effective. Pollen is normally shed from morning to afternoon, with midday the most optimal time to pollinate. Warm, sunny days with low humidity are ideal conditions for hand pollinating.

However, even if conditions are less than ideal, it never hurts to try anyway. Oftentimes, you can simply shake the plant(s) gently to distribute the pollen.

However, you may achieve better results by giving the vine a little vibrating instead. While you can purchase commercial pollinators or electric vibrator devices to hand pollinate tomatoes, a simple battery-operated toothbrush is really all you need. The vibrations cause the flowers to release pollen.

Techniques for hand pollinating vary, so use whatever method works best for you. Some people simply place the vibrating device (toothbrush) just behind the open flowers and gently blow on or shake the plant to distribute the pollen. Others prefer to collect the pollen in a small container and use a cotton swab to carefully rub the pollen directly onto the end of the flower stigma. Hand pollination is usually practiced every 2-3 days to ensure pollination occurs. Upon successful pollination, the flowers will wilt and begin fruiting.