Bees are the best choice for natural pollination in a greenhouse, and yes, you can keep bees in a greenhouse, however your choice of bees will determine how successful you will be at keeping bees in a greenhouse, glasshouse or polytunnel, with bumblebees being the most common choice of commercial greenhouse growers.
Greenhouses are ideal protected, climate-controlled spaces for plants to flourish.
However, because a greenhouse is an artificial environment, it is not going to provide the plants with those industrious insect pollinators that are responsible for doing all of the hard work of getting your flowers fertilized, and ready for the production of their fruits and seeds.
So, besides that you will need to pollinate the plants yourself (artificial pollination) using a Q-Tip and your hands!
If you are wondering the question “Can you keep bees in a greenhouse” this article outlines everything you need to know about the possibilities of using bees, and even housing bees, in a greenhouse.
We are going to outline what’s possible and what’s not with pollinating the plants in your greenhouse using bees.
For a Thriving Greenhouse, You Really Need Bees Onside
According to the US Pollination Handbook, our consumption of food contains one-third of us needing pollination from bees.
So if you want natural pollination in your greenhouse plants there is no getting around bees; you need other insects that pollinate as well.
When it comes to insects, bees are by far the most populous and most active pollinators. Bees are key to the transfer of pollen from male to female parts of flowering species.
Without pollination, plants and crops will not reproduce and produce seed.
Bees Are Pollinating Powerhouses
Indeed, bees have to do this. Pollen serves as a prime source of protein for honey bee colonies and that is what they feed the larval bees within the colony or hive.
Honey bees have evolved to forage flowers and harvest pollen most effectively so that they can take the most pollen back to the hive.
The hairs on their bodies operate in a “velcro-like” fashion to work as an electrostatic charge that allows the pollen grains to stick to their hairs.
Then, with stiff bristle-like hairs on the backs of their legs, they comb and mold the pollen into baskets to maximize the amount of pollen they take back to the nest.
Honey bees also improve their efficiency and efficacy in pollinating when they visit and feed on only one flower species at a time:
- This supports the transfer of pollen among flowers of the same species and at the same time supports the prospect of greater success in cross-pollination, which is more favorable than less viable offspring plants with seeds in more plants.
- Bees are attracted and rewarded with nectar (a sugar solution) that bees utilize for energy as they work.
Unless Your Greenhouse Is in Kew Gardens, Honey Bees Are Unlikely to Thrive in an Enclosed Greenhouse
Honeybees may look like an obvious choice for your greenhouse squashes, grapes, and melons, but they might struggle to adapt to such an unusual environment for several reasons:
- Honeybees struggle with orientation and die at high rates in greenhouses. They do not comprehend that they cannot pass through the greenhouse’s glass panels, and greenhouse owners will frequently lose them to the glass regardless of the size of the opening created.
- Honey bees utilize the sun to orientate themselves to the hive and nectar source, so their initial navigation can be difficult in a greenhouse. Honey bees also need seasonal temperature fluctuations.
- Space is critical to honey bees, and therefore they may be okay in a large commercial glasshouse environment. However, the stress of confinement will be challenging in a small greenhouse, and the count of plants will not be sufficient to sustain a colony.
- Some enthusiastic greenhouse owners can manage a small hive in a greenhouse by providing an exit for bees, or place frosted glass and use pheromones to encourage the bees to re-orient and stabilize the colony. Greenhouse owners supplement the carbohydrates for bees by feeding bees fondant to provide honey bees additional energy. In some cases, greenhouse owners frost the window panes to discourage bees from flying into the glass.
Your Greenhouse Residents Do Not Need to Be Honeybees
Although honey bees are highly regarded pollinators, many other bee species also do labor for pollination.
There may be specific bee species; however, we are focusing on the warm weather suggesting ground-nesting bee species.
Like so many wild bees, they do not have a hive. They nest in the ground or among cracks in masonry, wood, plant stems or tree cavities.
Bumblebees even nest in abandoned rodent nests, customizing their homes with materials they found to forage such as leaf litter, small stones, sap, and mud.
They even make a waxy product that serves as a mortar to create spaces to lay eggs.
Nesting Bee Species Will Appreciate the Year round Warmth and Predator-free Comfort of Your Greenhouse
For some species of bees, autumn and early winter are spent in search of a warm dry space for hibernation. Your greenhouse could be a dream come true!
A greenhouse has the warmth bees need to prevent freezing to death, as well as being protected from predators.
Queen bees that are entering hibernation rely on fat reserves to sustain them, this means they could be dormant for as long as 9 months in the year!
Good to Know: Only bumble bee queens survive winter and with a greenhouse as a residence, they easily have a pleasant, helpful retirement
Bumblebees Are Widely Used in Commercial Greenhouse Production
Bumblebees are housed in greenhouses by commercial growers that require pollinators throughout the growing season.
Research suggests using bumblebees as natural pollinators can provide a higher fruit yield and better overall crop quality.
- Bumblebees demonstrate remarkable efficiency as pollinators and outperform greenhouse workers engaging in artificial pollination of flowers. This allows growers to save labour time and costs.
- Growers can acquire hives of Bombus impatiens bumblebees from commercial bumble bee producers. They purposely rear bumble bees for pollination under glass.
- Prior to introducing bumblebees to a growing environment, make sure to cease using any insecticides to prevent pollinator poisoning. Most growers introduce new hives every week from their last previous hive as bumblebee colonies live between 5 and 12 weeks for consistent pollinations.
Using Bombus Impatiens as a Greenhouse Pollinator
Bumblebee colonies are a great way to pollinate many vegetable and fruit crops.
They are utilized to pollinate many commercially grown crops such as:
- Tomatoes
- Peppers
- Strawberries
- Cherries
To illustrate how many bumblebees you will be getting in one hive (growing on the scale of a commercial greenhouse), is that there are 60+ bees in each hive that can cover an area of 5,000 square feet. These bees gather pollen in their hairy hind legs and abdomens.
Bee supply companies will send you a complete hive that includes a colony with pubae, eggs and larvae and will ship the hive via courier.
Once you receive the hive, it is sent with a sugar solution to feed the bees during transport and during the transition to the greenhouse.
When it is time to release the bumblebees, growers can position the hive to be released from a height of 1-3 feet from the ground and should not place a hive filled with bumblebees close to greenery.
When releasing the bumblebee hive, they should be allowed to calm down for a period of time, such as 1 hour or more.
Once they appear calm, the tubes on the side of the hive can be opened to allow the bumblebees to forage.
Remember: Every evening the V vents should be closed to prevent bumblebee loss.
You Have Lots of Options for Wild Bee Species That You Could Attract to Your Greenhouse
Smaller greenhouse owners can host wild types of bee species that may want to set up residence inside the greenhouse.
There are over 270 species of bee in the United Kingdom alone, and 20,000 species worldwide that do not form colonies or hives. These ‘solitary’ bees are incredibly effective pollinators.
According to the Wildlife Trusts, solitary bees do most of the pollination in Britain.
Diversity in solitary bees suggests that there are probably some neighbouring solitary bee species that will adapt to the greenhouse conditions and collect pollen in a wide range of sources, even sources that honey bees wouldn’t be able to use.
Here are a few potential solitary bee visitors to your greenhouse:
- Mining bees are a modest and neutral solitary bee species that make their nests in the soil and collect pollen on their hind legs.
- Mason bees make their nests in the gaps or cracks in masonry. They regularly forage mud to build their nests, which they use to mortar the gaps together. Their tubular nests are the place that they lay their eggs, creating individual cells with mud. While mason bees use mud in their nests, they also collect pollen to take back to their nests.
- Flower bees, very similar to bumble bees, have very long tongues for probing flowers, drinking nectar, and collecting their pollen supplies on their hind legs. They are always looking for the best nesting places to make a colony.
- Sweat bees collect their pollen on the underside of their bellies, and/or keep it in their crop for when they return to the nest to regurgitate. Sweat bees will live in the soil and are variable solitary bee species or social. Consulting trustworthy sources however, can mix the two together.
Attracting Bees to Your Greenhouse
If you don’t have a hive inside your greenhouse, you need to make it an attractive one to entice the pollinators you need to stop by.
Here are some top tips on how to attract bees to your greenhouse or polytunnel:
- Your first task will be to ensure that there is sufficient access for visiting bees to come in and out of the greenhouse while preventing other pests from having free reign.
- Open the roof ventilation windows of the greenhouse so the bees can let themselves in and out.
- The bees will be able to fly into the greenhouse using airflow from the open ventilation widows.
- Make a visit to your greenhouse an attraction by including longer flowering plants that have nectar, fragrance and colour.
- Flowers that will attract pollinators are:
- Lavender
- Mint
- Lemonbalm
- Calendula
- Dill
- Fennel
- Borage
- Note: These flowers should be planted in and outside of the greenhouse to attract them in.
- Flowers that are blue will be attractive to pollinators and also yellow.
- Grow flowers that will flower and mature at different times. In this way, you can ensure that nearby and visiting bees have a constant supply of pollen and will develop the habit of visiting the greenhouse regularly.
- Avoid growing the same plant in a single area, since pollinaors will lose interest after it has stopped flowering.
- Do not allow it to get too hot in the greenhouse since excessive heat can kill the bees.
- Consider that you might provide a water source for the bees.
- You might also add a bee hotel for solitary bees.
For more on bee hotels see our article “What Is A Bee Hotel? A Beginners Guide To Garden Bees.” Hotels”.
As Winter Rolls in, Make Your Greenhouse the Place Where Bees Can Overwinter
Solitary bees and bumblebees appreciate a crevice or gap in which to build a nest.
You might consider creating a bee hotel out of a solid brick with ventilation holes or a piece of wood with holes drilled into it to provide for them.
Remember to leave some leaf litter or debris in the greenhouse for the opportunistic bees to use to furnish their nests.
Solitary bees will utilize exposed soil, too.
Rounding Up
Undoubtedly bees are the best bet for pollination in your greenhouse, but it can sometimes be hard to get a beehive to thrive.
But you can surely identity ways to make your greenhouse appealing to wild solitary bees and bumblebees, who will more than likely make a success of adapting to this unusual environment.