Most gardeners understand the birds-and-bees aspect of getting fruit to grow. There’s a male flower and a female flower. In most cases, if you want to get fruit, the male flower needs to fertilize the female plant in a process called pollination.
Not all female cucumbers require pollination. However, the female flowers of homozygous and non-hybrid cucumbers do require pollination. Gardeners have bred some cucumber strains specifically designed not to need fertilization, and these should be kept separately from plants with male flowers.
There is not a high chance that you’ll accidentally wind up with cucumbers that don’t require pollination. However, pollination is a must unless you’ve sought those out. Read further to find out how it works.
Three kinds of cucumbers constitute the species:
Monoecious cucumbers have male and female flowers. Left to their own devices (and the comings and goings of bees and other pollinators), they’ll breed as they should and provide delicious cucumbers for you to pick from your garden.
You can tell a cucumber flower’s sex by looking at its base. Both sexes are yellow flowers, and the male cucumber flower sits on a stem directly attached to the plant stalk. Female flowers, however, have what looks like a miniature cucumber underneath them. It sits between the flower and the plant stalk.
Gynoecious cucumbers have only female flowers and are designed to allow for a short growing season. By flowering quickly and for only a short period, they get pollinated and produce the same number of cucumbers any other plant would over its growing season. The difference is that the gynoecious cucumbers produce the fruit all at once.
Gynoecious cucumbers, however, need pollinating, though, for this growing season to happen.
Parthenocarpic cucumbers have female flowers only, and do not require pollination.
A more in-depth discussion of the three cucumber types is available in my other article if you are interested: Why Do Your Cucumbers Only Have Female Flowers?
However, the take home message is that unless you have parthenocarpic cucumbers — and you won’t likely have these by accident— your flowers will require pollination.
It’s no secret that bees (by far nature’s number one pollinator) are in danger and are experiencing a population decrease. This spells disaster for agriculture since pollination makes fruit possible.
Pollination requires a pollinator as a third party to the male and female flowers. The process involves these steps:
- A bee or butterfly alights on a male flower.
- The anther in the middle, with pollen on it, drops some of that pollen onto the pollinator.
- The pollinators eat the pollen, which is why they showed up to the flower in the first place, but in the process, they get pollen on their bodies and legs.
- The bee, having eaten its fill of pollen, moves to another flower in search of nectar.
- It lands on a female flower and, as it drinks the nectar, the pollen stuck to its body and legs transfers to the pistil.
- The pistil uses the pollen for fertilization, which produces ovules that become seeds and ovaries that become fruit.
Without pollinators, you can rely on the wind to pollinate your female flowers, but the success rate of that method will be low and hit-and-miss at best.
As mentioned earlier, parthenocarpic cucumbers do not require pollination. They are, by nature, also gynoecious, so there are only female flowers. This lack of male flowers is essential to note.
When you buy seeds for gynoecious cucumbers, you’ll find that a small number of seeds in the package are differently shaped or perhaps of a different color. These seeds produce male flowers.
The gynoecious cucumbers will produce only female flowers and this will happen all at once. However, without pollinators, all you’ll have is a plant with some pretty yellow flowers on it.
The other seeds in the package should be planted near the others so that the pollinators can get the pollen from the male to the female flowers.
Parthenocarpic cucumbers don’t need pollination but if they do get pollinated, they will produce bitter fruit.
The possibility of pollination and the resulting bitterness means that most gardeners decide to grow this type of cucumber indoors or in a greenhouse. It’s much easier to ensure that no stray pollinators wander onto your flowers if you can control what insects can get to your plants.
Since parthenocarpic cucumbers are often grown by large-scale operations, greenhouse space usually isn’t a problem. However, some gardeners use parthenocarpic seeds to hurry the fruiting process along. They might do this if they live in a place with a short growing season, or are looking to get another crop planted in the space where their cucumbers currently live.
Parthenocarpic cucumbers are hybrids, so when looking for this type of seed, you’ll want to specify “hybrid” in your search. Also, most of the seeds labeled “non-GMO” won’t be parthenocarpic.
There are several varieties to choose from:
- For a nice slicing cucumber, look at the seeds for the Sweet Success (available on Amazon.com) cucumbers. These seeds will produce sweet fruit and come in packs of 20.
- Two Beit Alpha varieties are Socrates, for cooler climates, and its warm-weather counterpart, Katrina (available on Amazon.com) cucumbers (which are non-GMO and come in packs of 100).
- The H-19 Little Leaf (available on Amazon.com) cucumber seeds will serve you well in a container garden.
Many cucumber seeds— of all varieties, not just parthenocarpic ones— are hybrids, meaning they have been cross-bred from different strains to create a new kind of cucumber.
This cross-breeding stems from the work of Gregor Mendel, the father of modern genetics. He spent time cross-breeding pea plants to determine which traits get handed down through generations and how that happens.
Most hybrids we plant in our gardens these days are known as F1 hybrids. We’ve learned that inbreeding can introduce or exacerbate genetic flaws, so hybridization aims to address those issues.
While cucumber plants have male and female flowers, many plants have flowers that can pollinate themselves. The resulting offspring are homozygous, and those offspring will produce more of the same, and genetically identical plants.
By cross-breeding, gardeners can, much as Mendel learned to do, select traits they want to keep and breed out any undesirable traits.
The F1 designation is simple: the F stands for “family,” and the 1 indicates the first generation. So the offspring of two homozygous plants is an F1 hybrid. Many parthenocarpic cucumber varieties are F1 hybrids, as are most gynoecious plants.
How To Encourage Cucumber Pollination
Since your female flowers probably need pollination, you can do several things to help that process along.
Some gardeners have more than just their food garden, planting separate flower beds to attract pollinators. A few flowers to plant in such a garden include:
- Black-eyed Susan
- Purple coneflower
Herbs can bring pollinators, too. Some herbs appear in butterfly gardens for the sole purpose of attracting, feeding, and nurturing caterpillars that will grow into butterflies— more pollinators for your garden. Some of these herbs are:
When planting these pollinator-friendly plants, remember that pollinators don’t see very well, so you’ll want to plant in clumps, keeping the flower colors uniform. You don’t want a patch of zinnias with yellow, red, white, and purple flowers in one place. Instead, pick one color and plant a group of them.
Hand Pollinating Cucumbers
If you don’t have room for extra flowers, or if you’re in an area where pollinators are rare or ineffective, hand pollination may be in your future. It’s a time-consuming procedure, but it isn’t difficult.
With a paintbrush or cotton swab, touch the anther, which will have the yellow, powdery pollen on it. Then touch the paintbrush to the center of the female cucumber flower, and the process is complete.
You’ll want to keep an eye on your brush or swab and keep replenishing your pollen supply.
Unless you have chosen a strain of cucumber seed that produces flowers that don’t need pollination, your female cucumber flowers require pollination. To complete the fertilization process, your monoecious or gynoecious cucumbers need pollinators.
Pollination can take place through bees, butterflies, or your own efforts. Without it, you won’t have any fruit to grow. If you’re using seeds from the cucumbers you grew last year, they’ll need pollination to produce, and this applies to most seeds you buy, too.
You can read my other article on how to increase your cucumber yield here: 10 Farming Secrets to Increase Your Cucumber Yield