Hand pollination

Hand pollination (also called "mechanical pollination") is a technique used when natural, or open pollination is insufficient or undesirable. The most common techniques are for crops such as cucurbits, which may exhibit poor pollination by fruit abortion, fruit deformity or poor maturation. Hand pollination is only an option on a small scale, but is a common technique by gardeners who transfer pollen with an artist brush or cotton swab. Sometimes the corolla is removed from male flowers and the flower itself is brushed against the stigmas of female flowers.

Hand pollination can be the simple act of shaking, with tomatoes and other self fertile flowers. Tomatoes grown in greenhouses generally need aid in pollination, and this has been done by hand or with an electric vibrator for a long time. Recently it has been mostly supplanted by cultured bumblebees.

When pollination is needed on a large scale, such as for field crops, orchards or commercial seed production, honeybees or other pollinators are cultured and provided for pollination management.

The primary reason for hand pollination is lack of pollinators which may be due to crops being moved from home areas (as in vanilla beans) without also taking the natural pollinator. Pollinator decline or the concentrated pollination needs of monoculture may also be factors in pollination shortage.

Another reason for hand pollination is in order to control the parents of the seed to be produced. For example, all F1 hybrids are the result of pollinating one specific variety with another specific variety, in order to produce a uniform crop.

For pest prevention with some high-value crops, row covers of mesh are used to prevent pest insects from access to the plants. However, this may necessitate hand pollination when bloom starts.

Hand pollination is used with date palms to avoid wasting a lot of space and energy growing sufficient male plants for adequate natural pollination.

Variable techniques for hand pollination have arisen for many specialty crops.