What’s the Buzz? Boost Pollination in Your Garden for a Great Harvest

What is Pollination?

When you watch bees buzz from flower to flower or butterflies flutter among blooms, the pollinators not only feast on the floral food—energy-rich nectar and protein-rich pollen—but they’re also making babies. Plant babies, that is.

As the pollinators dine, they’re transferring pollen from one flower to another. More specifically, these pollinators deposit pollen grains from the anther (the flower’s male structure) onto the pistil (the female structure).

Pollen can be transferred within an individual flower or between separate flowers. And, when pollination is successful, the plant produces viable seeds surrounded by a fruit to protect them.

Pretty sexy, huh?

Why is Pollination So Important?

Do you love the crisp crunch of apples? Enjoy sweet strawberries in smoothies? Do you cook with canola oil, slice bananas into your cereal, and savor scrumptious watermelon on the Fourth of July?

Thank a pollinator.

In fact, of the 1,400 food crops grown around the world, almost 80 percent require pollination by animals. More than half of the world’s diet of fats and oils come from animal-pollinated plants—palm oil, canola, and sunflowers. And more than 150 food crops in the U.S. depend on pollinators.

But while animals pollinate a lot of our food crops, some plants produce seeds via different modes of pollination. If you’re growing a vegetable garden, planting fruit trees, growing sweet corn, or cultivating berry shrubs, knowing how your plants are pollinated helps you understand how your plants produce delicious harvests.

When you know more about plant pollination, you’ll understand how you can help encourage pollination—and intervene when necessary. Think of it as Bio 101—without the grueling 8 a.m. lectures and $200 textbooks.

Demystifying the Types of Pollination

Biotic Versus Abiotic Pollination

Don’t let the terms intimidate you.

• Biotic pollination simply means that an animal pollinates a plant. About 80 percent of plants undergo biotic pollination.

• Abiotic pollination occurs without the involvement of organisms. Most abiotic pollination happens with wind, while a tiny portion occurs with water for some aquatic plants.

When growing fruits and veggies at home, most of your plants will undergo biotic pollination, with a few benefitting from the wind as well.

Biotic Pollination

Animal-pollinated flowering plants produce pollen that is sticky and barbed, attaching to the animal so that it’s transferred to the next flower. When you watch a pollen-covered bee travel from flower to flower, you’re watching your future dinner ingredients being created. (Thank you, bee!)

Curcubit Family Pollination

Plants in the cucurbit family—cucumbers, squash, zucchini, pumpkins, watermelon, and musk melons—depend on bee pollination. Each plant produces separate male and female flowers, instead of having both sets of reproductive parts in each flower. These “imperfect” flowers need bees to carry pollen from male flowers to female flowers, which is known as cross-pollination.

If you’ve ever seen loads of flowers on your cucumbers or squash—then despaired as the blooms disappeared without forming fruits—it’s not your fault. Honest. Many cucumber and squash cultivars produce male-only flowers in the first flush. During the second wave of blooms, both male and female flowers appear, ready for the bees to get busy with their pollinating chores.

However, if both male and female flowers are present, but you’re still not seeing fruit—it may be due to a lack of pollinators.

Cucumber Types for Pollination

There are four main terms for cucumber pollination requirements:

• Monoecious varieties produce both male and female flowers on the same plant and need pollinators.
• Gynoecious varieties produce only (or nearly only) female flowers. Some gynoecious varieties need a monoecious variety for pollination and to set fruit.
• Parthenocarpic cucumber varieties do not require pollination to produce fruit. If the plants are isolated from pollen-producing cucumber plants, their fruit will be seedless. One variety to look for is AAS Winner Green Light Cucumber.
• Parthenocarpic & Gynoecious in cucumber varieties together produces a large amount of all-female flowers without the need for pollenizer plants. These plants will also need to be isolated from pollen-producing cucumber plants to produce seedless fruit. AAS Winner Diva Cucumber is one of these varieties.

For more on cucumber types from our NGB member Johnny’s Selected Seeds, please click here.

Self-Pollination

Some plants can reproduce without pollinators—although pollinators tend to help boost harvests and increase genetic diversity. In self-fertile plants, a perfect flower contains both male and female reproductive structures. The anther opens, and the pollen lands on the stigma of the same flower. Pretty convenient, right?

Tomato, Pepper, Eggplant Pollination

Tomatoes, peppers, and eggplants produce perfect flowers that don’t necessarily need pollinators. Tomato anthers, for instance, form a tube that completely surrounds the pistil. Although the plant can produce fruit on its own, outside pollinators help increase fruit set and yield.

Wind shakes the pollen from the anthers onto the stigma. Bumble bees vibrate the flowers, shaking pollen loose onto the anthers. So, while these perfect flowers can produce fruit on their own, they do appreciate a little help from their pollinator friends.

Cross-Pollination

Unlike self-sufficient tomatoes, many plants require cross-pollination to produce fruit. And while bees can cross-pollinate male and female flowers produced on the same plant, like cucurbits, some plants have evolved to avoid self-pollination.

In these cases, a physiological barrier makes it difficult or impossible for a flower to fertilize itself, even though it may have been pollinated with its own pollen.

Self-incompatible Pollination

Many fruit trees, for instance, are self-incompatible. To produce fruit, two separate cultivars need to be planted near each other for pollination to occur. Bees play an important role in fruit production, visiting flowers from one cultivar and transferring the pollen to the other.

Most apples and pears are self-incompatible. For instance, a Braeburn apple blossom won’t set fruit if a bee deposits pollen from a second Braeburn apple tree.

Pollen needs to come from a cultivar that’s genetically different with an overlapping bloom time. Often, crab apples are used to pollinate apple tree varieties. Sweet cherries, pears, and many plums are also self-incompatible.

Self-compatible Pollination

Fortunately, some fruit is self-compatible—but still needs the help of pollinators to produce fruit. Tart cherries, peaches, raspberries, blackberries, gooseberries, elderberries, strawberries, and some blueberries, depending on the cultivar, are self-compatible.

Higher yield and better fruit set may occur with pollination from other cultivars, but it’s not absolutely necessary.

Wind Pollination

Some of the most important agricultural crops don’t need bees. In fact, most of the cereal crops—wheat, rice, corn, rye, barley, and oats—rely on a good breeze for pollination. Some nut-producing trees, like walnuts, pecans, and pistachios, also are pollinated by wind.

The pollen of wind-pollinated plants is lightweight, smooth, and small. Often, wind-pollinated plants produce flowers early in spring, before or as the plant’s leaves emerge.

This prevents the leaves from interfering with the dispersal of pollen from the anthers and provides easy reception of the pollen on the stigmas of the flowers.

Plant Sweet Corn in Blocks

Wind-pollinated plants usually occur in large populations, allowing the female flowers a better chance of receiving pollen.

If you grow sweet corn in your garden, for instance, consider planting it in blocks, rather than rows. By planting the corn in a square formation, the plants have a better likelihood of pollination, resulting in full ears.

A corn plant contains both male flowers—the tassels on top of the stalk–and female flowers—the silks on the ears. The silk is the elongated stigma. Each strand of silk corresponds to one kernel of corn. When grains of pollen from the tassel contact the silks, pollination occurs.

Mechanical Pollination

What’s a gardener to do when you’ve tended your green babies, nurtured them, spoiled them, watched them bloom—and they still don’t set fruit? If pollinators forsake your garden for the neighbor’s yard, you can still enjoy tasty treats—with a little extra effort.

Mechanical—or hand—pollination lets you play the busy bee or summer breeze. Instead of waiting for nature to take the lead, it’s time for you to intervene.

Corn

To hand-pollinate corn, cut the entire male flower—the tassel. Using it like a wand, shake pollen grains onto the female flowers—the silks. Or you can strip the pollen from the tassel, depositing the pollen by hand directly onto the silks.

You have a new appreciation for nature’s helpers now, don’t you?

Tomatoes and Cucurbits

Depending on your crops, mechanical pollination may be as simple as gently shaking tomato plants to help pollen drop onto the stigma. Or you may need to play artist by painting pollen onto the female flowers of cucumbers.

When hand-pollinating plants in the cucurbit family, you’ll need to identify the male and female flowers. Male flowers are typically the first to appear. Female flowers show a distinct swelling just at the base of the flower—a miniature fruit, just waiting to form. Take a male flower, revealing the stamen at the center—you’ll see pollen clinging to the stamen.

Using a small artist-style paintbrush, collect the pollen and touch it to the center of a female flower—the stigma. After pollinating three or four female flowers, collect more pollen from another male flower, continuing to pollinate the female flowers. (It’s best to do this in the morning.)

Invite More Pollinators to the Garden Party

If you’ve found your vegetable garden to be a bit pollinator-lite, consider taking steps to draw pollinators to your plants.

• Plant a diverse garden for season-long bloom in or near the veggie garden.
• Create habitats for ground or cavity-nesting bees.
• Avoid insecticides. Even “natural” products can harm bees and pollinators.
• Place a shallow dish filled with pebbles and water for a pollinator drinking station.

Welcome pollinators to your garden, and hopefully you’ll enjoy a bountiful harvest without the need to play pollinator. After all, it’s much more fun to watch the pollinators at work than actually work at pollination.

And, when you enjoy a delicious dinner from your garden, remember to raise a glass to pollinators in appreciation of their work.

About National Garden Bureau

Founded more than 100 years ago, the National Garden Bureau educates, inspires, and motivates people to grow home gardens. National Garden Bureau members are horticultural experts, and the information shared with you comes directly from these experts to ensure your gardening success.

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