Tomato plants are self-pollinating and have "perfect" flowers. Photo by Ali Graney under the Creative Commons Attribution License 2.0.
Giving your tomato plants a little daily shake will help produce more fruit. Photo by Deb Roby under the Creative Commons Attribution License 2.0.
The pollination of tomato plants has been the subject of controversy by many a gardener over just as many years. You’d think that we could just ask those who have been growing their own food for decades (the “seasoned” gardeners) for the final answer.
The problem is that those are the very gardeners that are having the debate. Like many things in gardening, it appears that there are still mysteries out there for us to discover. And it’s probably just as well; mysteries make us become observant and curious. Both important attributes for humans to possess, yes?
First, let me say that tomatoes are “self-pollinating” plants. They have what’s called “perfect” flowers. What this means is that they have flowers that have both the stamen and the stigma (male and female parts) on the same blossom. So, the pollen from the stamen falls onto its own stigma and we have pollination and eventually, fruit. Often this is process has been completed before the flowers are fully open – but not always. Beans, eggplant and peppers are self-pollinating, too.
Some gardeners say that tomato cross-pollination (the pollen from a different tomato variety pollinates another variety) happens on a regular basis. Some argue that in all of their gardening years, they’ve never seen a tomato cross-pollinate in their garden no matter how close the proximity. Still others strongly suspect that the answer lies somewhere in-between. While tomato blossoms are structured basically the same way – they have a perfect flower that allows for self-pollination – some tomato species have an extra long “style” which is part of the female reproductive part of the plant.
The end of the style (stigma) is where the pollen grain sticks to that ends up producing fruit. The idea is that if the style is very long, it may make it possible for other insects to pollinate the flower before its own pollen can drop onto the stigma. On the other hand, tomato species that have blossoms which carry a short style make it nearly impossible for outside (cross) pollination.
Whatever the deal is, you can actually help your tomato plant set more fruit this season by showing it some tactile love. You just take the flowering branches and give them a gentile shake. The pollen will drop from the stamen of the flower onto the pistil.
There’s no magic number of times you should shake your tomato plants; you just sort of wing it. Gardeners usually do it two or three times a day to ensure good pollination. Left alone, the wind would shake the blossoms, as would the fluttering of bees’ wings. But, gardeners everywhere swear that they harvest higher fruit yields with this simple technique.
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