If you’ve been growing strawberries under cover, don’t forget you can help with their pollination It’s April and the strawberries in my polytunnel are starting to flower, which is great! However, although strawberries are self-fertile (which means they are self-pollinating) they may need a little help if you’re growing them under cover.
The simplest thing to do is to leave the doors open so that insects can find their way in. You can also pollinate by hand by stroking the stamens with an artist’s paint brush. This will ensure that the pollen with make contact with he stigma in the centre of the flower. If it’s not too cold in spring and your strawberries are in pots, you can move them outside in the day – but watch out for frosts as these will kill your strawberry flowers and you will not have any berries !
By making sure your strawberry flowers are fully pollinated you can expect a better crop. Article continues below. Advert 
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Contents
Can you self pollinate strawberries?
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- Estoy de Acuerdo / I agree Collapse ▲ Strawberry flower morphology and seed set Strawberry flowers have both male and female parts on each bloom.
The male parts include the pollen carrying portion of the flower (highlighted in blue) and pollinators must come into contact with this area to collect pollen grains. The female parts of the flower (highlighted in pink) must individually receive pollen grains to attain complete pollination. 
Strawberry flower. Photo: Jeremy Slone Lack of complete pollination in each pistil (female flower part) can result in smaller or misshapen berries, meaning reduced yield of marketable fruit. Poorly pollinated berry (left) and a misshapen berry (right). Photo: Jeremy Slone The actual berry forms from each pistil developing into an individual “seed’ that is actually an individual fruit, called an achene. The fleshy red part of the strawberry is rather an enlarged receptacle that holds the achenes ( Poling, 2012 ). 
Berry development from each pistil being pollinated into individual achenes. Photo: Jeremy Slone As seen in the photo below, there are many ways for pollen to be transferred within the flower and unlike some crops, strawberries are self-fertile. However, maximum yields are possible with a combination of self-pollination (pink), wind (blue), and insects (green).Although flowers are capable of self-pollinating, each pistil must receive pollination, and studies have shown that self-pollination and wind-blown pollen are often not sufficient to completely pollinate a flower. 
Different modes of pollination on each flower. Photo: Jeremy Slone References:
Klatt, B.K., Holzschuh, A., Westphal, C., Clough, Y., Smit, I., Pawelzik, E., & Tscharntke, T. (2014). Bee pollination improves crop quality, shelf life and commercial value,R. Soc. B, 281, Wietzke, A., Westphal, C., Kraft, M., Gras, P., Tscharntke, T., Pawelzik, E., & Smit, I. (2016). Pollination as a key factor for strawberry fruit physiology and quality, Berichte Aus Dem Julius Kühn-Institut, 183, 49–50. Zebrowska, J. (1998). Influence of pollination modes on yield components in strawberry (Fragaria x ananassa Duch.), Plant Breeding, 117 (3), 255–260.
(Written by Jeremy Slone, August 2016)
Do strawberries need to be pollinated to fruit?
Strawberry flowers need to be pollinated. Uneven pollination usually results in misshaped fruit (Fig.1). Strawberry flowers are most effectively pollinated by honeybees. A recommended bee hive size for greenhouse strawberry is one with 6,000 to 8,000 bees per 1,000 m2 greenhouse with a typical planting density of 8-10 plants per m2 ( Mitsubachi Kyogikai, Japan), which is translated as approximately 11,000 sq feet per small hive.
Such small hives with a bee population of several thousand per hive are available to rent or purchase in countries like Japan (Fig.2) where average size of greenhouse strawberry production is small (~20,000 square feet). However, in US, as far as we are aware, such a business offering small honeybee hives (less than 10,000 bees per hive) has not been developed yet due to the limited market.
Typical bee hives used for open field crop production seem to be at least several times bigger than what future strawberry growers would need for small scale local production in urban or suburban settings. Use of bumblebees is more common for greenhouse and high tunnel growers in the US, because honeybees do not function well in most American high tunnels (the typical glazing limits UV light transmission) and honeybees are more challenging to manage when there is competition from other flowers available in nature or in other neighboring crop fields.
Winter strawberry production in greenhouse, however, is a unique situation where not much competition exists from flowers outside the greenhouse (i.e., off season), and therefore the flowers in greenhouse are the main attraction for the bees. Bumblebees work well in greenhouse tomato and their use is an industry standard.
And, introduction of bumblebees to strawberry greenhouse is possible; however some careful consideration is needed before doing so. Bumblebees are more active than honeybees, being able to visit more flowers per flight. This is why considerably fewer bees (~20 bees per 1,000 sq feet, per Koppert Biological Systems ) are introduced for bumblebees than for honeybees for pollinating the same number of flowers.
Therefore when the bumblebee population is high relative to the number of flowers, bumblebees tend to damage the flower (and also the receptacle that develops into fruit) by making too many visitations, and too vigorously harvesting pollen during each visit, resulting in abnormally shaped fruit. When growers must use bumblebees for strawberry, care should be taken to manage bee visitations to the flowers by limiting the bee’s access to the crop by temporarily closing flight holes (exit for bees) on the beehive for prolonged periods during the day.
Providing supplemental pollen to the hive is probably necessary with restricting pollen gathering by the bees. Per several available sources for information of honeybee management in greenhouse (e.g., Mitsubachi Kyogikai, Japan), there are several key issues.1) Avoid using UV protected greenhouse glazing.
- Honeybee visible light ranges from 300 nm to 650 nm (for humans it is 380 to 780 nm) and complete exclusion of UV range (300-400 nm) substantially affects honeybee activities.2) Using honeybees in winter is contrary to their natural life cycle.
- Understanding their life cycle and seasonal environmental effects on the bees, especially temperature and light, is crucial in bee management in greenhouse.3) When you need to apply pesticides, potential impact on bees must be known.
If necessary, moving bee hives to a temporary location needs to be considered. Strawberry flowers are also pollinated by wind that vibrates the flowers to shed pollen from anthers onto pistils. An alternative way to pollinate strawberry flowers is using a tool to vibrate the flower at a high frequency.
- An electric pollinator (Figure 4) is an effective tool for small scale greenhouse operation.
- A few seconds of vibration can be applied for individual flower clusters.
- When you apply this method, flowers (anthers) need to be dry so that pollen will disperse more evenly.
- Use of leaf blowers may be effective but careful use is recommended to avoid mechanical damage to plant stem and leaves.
(Updated 10/3/13) Figure 1. Abnormally developed fruit. Figure 2. A small hive for honeybees in a small greenhouse (Photo credit: Honjo Farms, Japan). Figure 3. Bumblebees on tomato flowers (Photo credit: Efren Fitz). Figure 4. An electric pollinator used in our greenhouse.
- Arizona Pollination of Strawberries in Greenhouse’ video produced by Dr.
- Mike Evans at University of Arkansas.
- University of Arizona collaborates with Dr.
- Mike Evans for developing series of educational videos to learn hydroponic strawberry production.
- Visit the Hydroponic Strawberry YouTube Channel,
- This project is funded by a grant from the Walmart Foundation and administered by the University of Arkansas System Division of Agriculture Center for Agricultural and Rural Sustainability.
Any products, services or organizations that are mentioned, shown or indirectly implied in this website do not imply endorsement by the University of Arizona.
Can you artificially pollinate?
Hand pollination, also known as mechanical pollination is a technique that can be used to pollinate plants when natural or open pollination is either undesirable or insufficient.
What pollinates strawberries?
Both female and male parts of the strawberry plant are on each flower of most cultivated varieties. Bees, as well as other insects, transfer the sticky pollen from the anther (male) to the stigma (female). Stigmas are often receptive before pollen of the same flower is available, which encourages cross pollination.
Do strawberries need to be fertilized?
Strawberries – Established strawberries should be fertilized once per year after the final harvest. Spring fertilization is not recommended because it can result in soft berries and overly vigorous growth that can increase the incidence of disease. Spread 8 ounces (one cup) 10-10-10 or 12-12-12 evenly over a 20-foot row.
Do tomatoes self pollinate?
Problems with Pollination in High Tunnel Tomatoes I’ll start with a quick recap as to how tomato flowers are pollinated and fertilized. Tomatoes are self-pollinated at the rate of around 96% of the time. Tomato flowers are complete flowers that have both male (stamen) and female (pistil) parts within the same flower.
- The yellow anthers (produce pollen) of the stamen wrap around the pistil which is in the center of the flower.
- The style with the stigma on its end is the part of the pistil that extends above the anthers.
- Tomato pollen is heavy and sticky and needs to be jostled loose from the male to fall onto the female.
This ‘jostling’ can include wind or insect visits. Once pollen is shed onto the stigma of the flower fertilization can take place. Without pollination the pedicle turns yellow, the flower dies and then drops. Tomato flowers must be pollinated within 50 hours of forming or they will abort.
Pollination usually occurs between 10 a.m. and 4 p.m. One of the most important factors affecting pollination is temperature. Tomato plants will drop their flowers when daytime temperatures are above 88°-90°F or when nighttime temperatures are above 70°F. These temperatures occurred in our HTs these last few weeks.
However, in the early part of the season low nighttime temperatures below 55°F can interfere with the growth of pollen tubes or cause the pollen to become sterile, preventing normal fertilization and causing flower drop. Fruit will not set until nighttime temperatures are above 55°F for at least two consecutive nights.
- Fig.2 Bumblebee visiting tomato flower results in pollination.
- Fig.3 Top flower not visited by bumblebees; bottom flower was a few times.
- Besides temperature the other big problem causing poor pollination in high tunnels is poor flower vibration or ‘jostling’.
- Because tomatoes are in high tunnels they may not always be exposed to winds that will help ‘jostle’ the tomato flower, which releases pollen.
Some other mechanism is needed at times to vibrate tomato flowers to increase pollination. The final size and weight of fruit is largely determined by the number of seeds set, which is ultimately due to the quality of pollination and fertilization. A HT tomato plant should produce between 20-30 lbs of fruit/plant, if it is not then poor pollination may be the cause.
My HTs produced around 18 lbs/plant and I conducted some trials to try and increase my pollination success using an air-blower that was passed over the plants every few days for just a few seconds after they started forming flowers. My per plant yields went from 18 lbs to 28 lbs and I was able to increase my marketable yield by 35-50% just by increasing pollination and fertilization in my tomato plants.
You do not have to use an air-blower to achieve better pollination and fruit set, most growers use bumblebees, which use sonication or buzz pollination. The bees will fly up to a flower and grasp the anthers with their mouth parts and hold tightly. They then vibrate their wing muscles which causes pollen to drop from the anthers onto the stigma causing pollination and at the same time the bumblebee gets to collect some of the pollen (fig.2).
- This grasping of the tomato flower by the bee leaves a mark on the flower (fig.3) and can be used by growers to see if bumble bees are visiting their tomato flowers.
- Studies have shown that just 1-2 visits by bumblebees to tomato flowers will result in greater than 80% fruit set vs no visits which result in approximately 30% fruit set.
The bottom line is that tomato pollination is a delicate balance between the correct temperatures and having enough flower vibration to ensure good pollen drop. If you are getting only 15-16 lbs/plant or less in your HT tomatoes you may want to examine how well your plants are being pollinated and just what your fruit set is like. or : Problems with Pollination in High Tunnel Tomatoes
Do you need 2 plants to pollinate?
Cross-pollination not needed – Most self-pollinating varieties will bear fruit perfectly without any pollen from other varieties: their own pollen is enough.
Sweet orange, ‘Temple’, ‘Lee’ and ‘Fallglo’ orange varieties and many other citrus self-pollinating apple, pear and other varieties Vanilla (an orchid actually) is self-pollinating
For some plants, the fruit appears even if the flower isn’t pollinated or fertilized. This is called parthenocarpy.
strawberry plant seedless watermelon seedless grape Ananas comosus
Of course, cross-pollination isn’t needed for all plants not grown for fruit or seed:
leaf vegetables and root vegetables flowers for the garden and flower shrubs (check if you want berries from them though) fragrant vines and indoor plants
Do indoor plants have to be pollinated?
Bees do so much for us, including pollination, but does that extend to your indoor plants as well? Even if, let’s say, your houseplants did need pollination, it’s not like there are any bees in your home to do it. What would you even do to get pollen? Do indoor plants need pollination? While most indoor plants do not need pollination, a few that do need pollination include: cucumbers, peppers, squash, tomatoes, & more.
How can we pollinate without bees?
Right now, millions of bees are hard at work on farms around the world, pollinating many of our favorite foods. Some say it’s as much as 7 out of 10 crops, Others say it’s one-third of all the food we eat. But the fact is, bees love all the same vegetables people do; they just happen to get to them a little earlier.
All bees want is some pollen and, in return, we get increased yields on billions of dollars of crops every year.While many plants benefit from honeybee pollination, few require it. The starchy staple crops that make up most of the calories humans eat – corn, wheat, rice, soybeans and sorghum – can all self-pollinate, so bees tend to leave them alone.
Bananas and plantains take things a step further by reproducing without any pollination at all. Pollination by bees and other insects–known as entomophily–is predominant in plants because it diversifies their gene pool, protecting them against disease.
But there are a few other ways plants can pollinate: by wind, water, rain and self-pollination, where a plant transfers pollen between its flowers on its own. Because plants have so many ways to reproduce, it varies how much each species “needs” bees. We know that honeybee pollination is essential for at least nine plants.
If honeybees were unable to pollinate farmers’ fields, these plants would be off store shelves – or much more expensive – within a year: – Kiwifruit – All melons, including cantaloupe – Squash – Pumpkin – Gourd – Zucchini – Macadamia – Rowanberry Honeybee pollination is considered “greatly important” for dozens of major crops, but a few popular ones include: – Cashew – Cilantro – Cucumber – Apple – Mango – Avocado – Blueberry (See the full chart here.) As you can tell, reports of humanity’s death have been greatly exaggerated.
Is hand pollination effective?
Hand pollination achieves nearly 100% fruit set, producing larger fruit containing more seeds (Patterson, 1989).
Can a flower self-pollinate itself?
Types of self-pollinating flowers – Both hermaphrodite and monoecious species have the potential for self-pollination leading to self-fertilization unless there is a mechanism to avoid it.80% of all flowering plants are hermaphroditic, meaning they contain both sexes in the same flower, while 5 percent of plant species are monoecious.
How do strawberries reproduce naturally?
Runners and daughter plants –
Strawberry plants reproduce through stolons or “runners.” Runners extend out several inches from the crown, take root in the soil, and produce new plants called “daughter plants.” In June-bearing strawberries, runners and daughter plants are necessary for the plants to spread and fill out the rows, but they are removed from between the rows. Runners are not needed in day-neutral strawberries, so they should be removed throughout the season.
Managing Strawberry Runners (Video: 00:01:29)
How do strawberries reproduce naturally?
Runners and daughter plants –
Strawberry plants reproduce through stolons or “runners.” Runners extend out several inches from the crown, take root in the soil, and produce new plants called “daughter plants.” In June-bearing strawberries, runners and daughter plants are necessary for the plants to spread and fill out the rows, but they are removed from between the rows. Runners are not needed in day-neutral strawberries, so they should be removed throughout the season.
Managing Strawberry Runners (Video: 00:01:29)
Do garden strawberries reproduce asexually?
Strawberries can reproduce both sexually and asexually. Sexual reproduction in plants involves the exchange of genetic information via pollination, seeds, and fruit. Asexual reproduction is when the plant reproduces vegetatively, essentially creating a clone of itself.
Are there hybrid strawberries?
The Strawberry: A Multiple Fruit When we think of fruits and vegetables, we’re pretty sure about which is which. We tend to lump sweet or sour-tasting plants together as fruits, and those plants that are not sugary we consider vegetables. To be more accurate, however, we must consider which part of the plant we are eating.
- While vegetables are defined as plants cultivated for their edible parts, the botanical term “fruit” is more specific.
- It is a mature, thickened ovary or ovaries of a seed-bearing plant, together with accessory parts such as fleshy layers of tissue or “pulp.” Thus, many of the foods we think of casually as fruits, such as rhubarb (of which we eat the leaf stalks), are not fruits at all, and many of our favorite “vegetables” actually fit the definition of fruit, such as the tomato.
As a subcategory of fruits, berries are yet another story. A berry is an indehiscent (not splitting apart at maturity) fruit derived from a single ovary and having the whole wall fleshy. Berries are not all tiny, and they’re not all sweet. Surprisingly, eggplants, tomatoes and avocados are botanically classified as berries.
- And the popular strawberry is not a berry at all.
- Botanists call the strawberry a “false fruit,” a pseudocarp.
- A strawberry is actually a multiple fruit which consists of many tiny individual fruits embedded in a fleshy receptacle.
- The brownish or whitish specks, which are commonly considered seeds, are the true fruits, called achenes, and each of them surrounds a tiny seed.
These achenes also make strawberries relatively high in fiber. According to the Wellness Encyclopedia of Food and Nutrition, one-half cup of strawberries supplies more fiber than a slice of whole wheat bread, and more than 70 percent of the recommended daily allowance of vitamin C.
The cultivated strawberry is a hybrid of two different parent species. Because they are hybrids, cultivated strawberries are often able to adapt to extreme weather conditions and environments. While California and Florida are the largest producers, strawberries are grown in all 50 states. Strawberries are a significant crop in Pennsylvania, but they have a relatively short season.
According to Carolyn Beinlich of Triple B Farms, a local pick-your-own berry farm in Monongahela, Pennsylvania’s ideal strawberry season lasts three and one-half weeks. The plants form their fruit buds in the fall, so adequate moisture at that time is vital.
- Since October 1996 was a rainy month, Beinlich is looking forward to a bountiful strawberry crop this season.
- The recipe shown here is among Beinlich’s favorites for celebrating the strawberry season.
- For more information about Triple B Farms, call 258-3557.
- Lynn Parrucci is program coordinator, and Amy Eubanks is a research assistant, at the Science Center’s Kitchen Theater.
Botanist Sue Thompson of Carnegie Museum of Natural History, also contributed to this article. *** Visit the Kitchen Theater at Carnegie Science Center to learn more about the science of cooking, and get a taste of what we’re cooking and a recipe to take home.
1 quart strawberries, washed and drained well, stems removed 3_4 cup white sugar 11_2 Tablespoons cornstarch 1 1/2 cups water 1 3-ounce package strawberry gelatin 1 9-inch baked pie shell
Boil sugar, cornstarch and water until clear (about 10 minutes). Mix well with strawberries and spoon into pie shell. Refrigerate three hours. Top with whipped cream if desired, and serve. Carolyn Beinlich of Triple B Farms will present a cooking demonstration on strawberries at the Science Center’s Kitchen Theater Sunday, June 1, at 1:30 and 3:30 p.m.