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Pollination Problems of Plants Growing Indoors
We will be focusing on the main issue that arises from the lack of proper pollination of zucchini plants in greenhouses or other indoor planting environments.
Zucchini plants will be our main example but all plants need to have some form of pollen transfer.
Greenhouses are a wonderful way to extend your growing season especially if you live in a cooler climate. But, they do come with some special considerations in regards to plant growing cycles. Properly pollinating garden crops is a very important aspect for a vegetable garden and gardening in general.
Related Post: Garden to Table Zucchini
Male and Female Blossoms:
Zucchini plants have both male and female flowers on the same plant. Zucchini plants belong to the family of curcurbita which are members of the gourd family. Other common vegetables in this same family are: pumpkins, squash, and cucumbers.
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Male Zucchini Flower -
Female Zucchini Flower
The male blossom develops on the end of the thin stem while the female blossom develops on the end of a small zucchini fruit as shown in the photos above.
Proper Fruit Development:
Please note: in the photos below, you see a small immature zucchini on the left which was not properly fertilized due to lack of pollen transfer by insects or air movement in our greenhouse. (Our greenhouse was closed due to cooler temperatures).
The little zucchini squash began to develop but was stunted and eventually started shriveling on the blossom end of the fruit. This was due to improper pollination.
The zucchini on the right was hand-pollinated with a small paint brush. Pollen from a male flower was gently gathered on a small paintbrush and was lightly dusted on the stigma in the female blossom.
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Improperly Pollinated Zucchini -
Properly Pollinated Zucchini Squash
Male Anther:
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Male Zucchini Blossom -
Zucchini Flower Stems are very noticeable as they are long and thin
The pollen in the above photo is surrounding the male anther which is the visible projection in the center of this blossom.
Make sure to look further down this post to see close up photos of a bee in this flower. The stamen, pollen and details of the blossom are highly visible.
Female Stigma:
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Female Zucchini Blossom -
Small Zucchini Fruit with Female Blossom
The female blossoms will open on the end of the small zucchini fruit. The blossom will have a cluster in the center of the blossom which are called the female stigma. This cluster of stigma is highly visible in the photo below.
Pollinating is Really for the Bees:
The easiest way to ensure proper pollination is by a healthy population of bees and insects. These little creatures move in and around the blossoms with a high probability of transferring pollen from the male anther to the female stigma and thus completing the process.
Photos of Pollen Covered Bee:
This particular bee was totally covered in fresh pollen. It was as if she was drunk with pollen. This little female worker bee crawled around the inside of the male zucchini blossom and finally tried to get out but was so heavy-ladened with pollen that she tumbled back into the flower.
Once the bee was actually able to make it out, she could barely fly being so completely covered with pollen. She finally took to the air but was flying low and slow!!! This little bee should have gotten a prize for due diligence!!!
Pollination in a Greenhouse:
Plants growing in a protected environment may not have proper exposure to bees, insects, wind or air movement. Without the transfer of pollen from the male flowers to the female flower, the zucchini fruit may not develop properly.
Another situation may compound proper pollination is with the number of plants currently growing in your location……like only having one plant in your greenhouse!!
What to do with one Zucchini Plant?
We only had room in our greenhouse for one zucchini plant as they take up so much space. Zucchini plants typically have a large leaf span and even more so in an ideal growing environment such as a greenhouse.
With only one plant, it was quite impossible to have both male and female flowers opening at the same time. Zucchini flowers typically open in the morning as the air temperatures warms.
Short Window to Pollinate:
The flowers only stay open for a short period of time. In order to ensure proper pollination, I hand-pollinated the female flowers with a small paintbrush. I gently gathered some fresh pollen from the male flower anther and dusted the female flower stigma.
Pollination of Zucchini Plants:
I was successful in proper pollinating on my second attempt. Here is the zucchini that has now fully developed and is almost ready to pick!!
If you have several zucchini plants, then allowing some air movement or even tapping the plants to encourage pollen distribution will help ensure adequate pollination for a successful crop.
Additional Ways to Ensure Pollination:
Along with bees and hand pollinating, also consider allowing some air movement or controlled wind to access your greenhouse or indoor growing situation. If this is not possible, then tapping individual plants will cause a stir of air movement and thus aid in pollen transfer.
The main point is to ensure proper pollination of zucchini as well as all plants for a healthy crop. It is a sad situation to go to all the work of planting and growing not to be able to reap a bountiful harvest.
This is a fun gardening adventure and is perfect for kids to learn the importance of bees, insects and the future of plants for food!
