Some plants may need hand-pollination, especially if there are no bees, such as the cucurbits, (cucumbers), melons, and squashes.
Offered by Toni.
Mother Earth News, Sep/Oct 78
This foolproof method of obtaining pure, true-to-type seed is ideal for cucumbers, muskmelons, watermelons, squash, pumpkins, peppers, eggplant, and corn ... all of which have large, easy-to-handle flowers and produce numerous seeds per blossom. (You can also hand-pollinate tomatoes, but since they're almost entirely self-fertilizing, this precaution is seldom necessary.) The cucurbits (cucumbers, melons, squash, and pumpkins) are insect-pollinated annuals. They have separate male (pollen-producing) and female (ovule-producing) blossoms. You can easily distinguish the two because the female flower includes a swollen ovary just below the petals. The male lacks this organ ... which will eventually develop into the fruit. To hand-pollinate, just follow these easy steps:
- On the day before a female flower is due to open, fasten it shut with a metal clip or rubber band (or whatever works). This precaution will keep unwanted pollen from fertilizing the blossom.
- On the following day pick a male flower from a different plant ... and expose the pollen-producing anthers by removing the petals.
- Then open the female flower and gently rub the anthers across the stigma (the enlarged pollen receptacle at the tip of the style or central stalk within the blossom).
- Finally clip the female flower shut again to prevent further pollination. Be sure to mark the blossom in some fashion so that you can later distinguish the fruit it produces from that borne by blossoms pollinated by insects.
You can hand-pollinate peppers and eggplant in much the same way ... except that their flowers are perfect ... that is they contain both male and female parts. So you just have to pick any flower from one plant and rub it against any other from a different plant. The receptive blossom of course should be clipped both before and after this operation. (Actually peppers and eggplant - like their cousin the tomato - are largely self-pollinating but bees visit these fruits so much that a good deal of crossing occurs anyway.)
Like the cucurbits corn plants have separate male flowers (tassels) and female flowers (the ears). Pollen formed on the tassels is carried by the wind to the silk (stigmas) produced by the ears. To hand-pollinate place white paper bags over selected ears before the silk appears. Secure the bottom of each sack with a rubber band or length of twine. When pollen shakes away from the tassels easily cut one off and rub it against the silk of ears growing on different plants. Then replace the bags until the ears mature.
Organic Gardening, Sept/Oct 1992
The Fine Art of Hand Pollination
by Suzanne Ashworth
All members of the Cucurbitaceae family (squash, gourds, melons, cucumbers, etc.) produce both male and female flowers on the same plant. In their search for food, insects pick up pollen from male flowers and deposit it on female flowers, randomly moving pollen from flower to flower. Cucurbits can be pollinated by almost any variety within their same species and the plants that pop up from seed produced by such crosses are often unusual and frequently bear little resemblance to the parent plants. To prevent this random pollination, you must keep insects away from the flowers that you want to ripen into the fruits you'll select for seed. You can start to do this as soon as the first flowers appear, but remember that summer squash are like cucumbers: If you don't keep the plant picked the fruit production slows, so you may want to let the plant produce for a while before you start to hand-pollinate. (With melons, gourds and other squash, you can start pollinating any time without interrupting production.)
Ready? First, you must learn the difference between male and female flowers. Female blossoms are attached to tiny, immature fruit which reveals itself as a bulge in the stem right be hind the flower. Male blossoms have straight stems. This is most easily seen in squash. Melons and chayote have very small flowers that make their gender a bit more difficult to identify. In the evening, select blossoms that look like they're ready to open the next morning. These will be beginning to show color and the petals will be beginning to flare outward. Choose a male flower from one plant to pollinate a female flower on a different plant of the same variety - this "sibing" will result in a greater degree of genetic diversity, which insures a healthier seed stock. (In case you were wondering, applying the pollen of a male flower to a female flower of the same plant is known as "selfing.")
Use masking tape to gently hold the blossom closed. Early the next day, remove the tape from the male flower, pick it and carefully tear off the petals, exposing the pollen-covered anthers. At this point, you may want to hold the stem of the male flower between your teeth in order to free both hands (who says garden sex isn't wild?) Now, gently remove the tape from the female flower. The flower should slowly open. Take the male flower and gently rub its pollen onto the stigma sections in the center of the female flower. Pollination will be more successful if several male flowers are used to pollinate one female flower. When you're done, retape the female flower's petals closed and mark the stem. You can mark that stem with string, yarn or any brightly colored durable material. The key word here is durable Your markers will be exposed to water, heat, light and birds looking for nesting materials. Poultry bands work exceptionally well; they expand, stay put and are reusable (you can buy them at animal feed and supply stores). Be sure you mark the actual fruit when you harvest it, too, so you'll know it's the one from which you want to save the seeds.