You can raise solitary hole-nesting bees inside of your greenhouse or high-tunnel and here are our tips to ensure they have what they need to pollinate your crops.

What bees need in your greenhouse or high-tunnel

1. Full Spectrum Sunlight - All bees have a set of 5 eyes which are made of 2 large eyes on the sides of their head and 3 simple eyes on the top of their head. These simple eyes are called ocelli and bees use them to tell the time of day and direction (north, east, south, and west). These simple eyes need the full spectrum of sunlight, otherwise bees can become confused or disoriented while flying. Ensure that your greenhouse or high-tunnel material does not block UV rays.
2. Plenty of Blooms - Each female bee can visit 2,000 or more open flowers per day. Make sure that you are growing enough flowers to feed your bees. If your structure is smaller, you can raise fewer bees to ensure that they are not competing with each other for pollen and nectar.  Each nesting bee needs about 1 square yard/meter of blooming flowers each day.
3. Natural Nest Building Material - Provide moist clayey mud for spring mason bees and set up the mud source about 5-10 feet away from the bee house, this will make it easier for the bees to bring the mud from the ground back to the nest. Make sure that your leafcutter bees have the right kind of leaves that they like to build their protective leafy cocoons - peas, beans, and smooth-leafed strawberry are easy to grow leaf sources.
4. Few openings to outside - Bees prefer open space and will look to escape a greenhouse. Cover vents and holes with fine netting to prevent bees from escaping.

What to buy for your greenhouse

If you are confident you are able to raise hole nesting bees within your green house, consider these suggestions:

1. If trying this for the first time, purchase reeds rather than wood trays. It should be important to see that the bees work for you before purchasing expensive equipment.
2. You don't need a house for nesting holes unless you have overhead sprinklers.  Place the nesting holes above the blossoms, about head height.
3. Moist clayey mud is a requirement for mason bees.  Wet dirt is not a substitute.
4. Tender leaves that leafcutter bees use for their nests is a requirement. 
5. Our invitabee should be part of your "proof of concept" for the first time.
6. Nesting bees each require about 1 square yard/meter of blossoms per day for their nesting needs.

If you are unable to make these changes to your greenhouse, you can simply open the door or vents on days with nice weather.

How do I pollinate greenhouses in the fall or winter?

1. Correct temperatures. The mason bees that we carry need daytime temperatures around 53-80F. Leafcutter bees should have daytime temperatures between 75-100F.
2. Correct amount of stored fats in body. Hibernating adult mason bees start with 100% full "fuel tanks" of body fats. By early spring, the fuel tanks may be less than 25% which tells the bees it may be fine to emerge if temperatures are correct. We know that mason bees with greater than 25% are slow to emerge, and much higher do not emerge at all. (Males that have depleted their fuel tanks will emerge within refrigerators.)
3. Age of bee. We have seen mason bees survive in refrigeration until mid summer, but they tend to be weak when emerged. We have held leafcutter bees in refrigeration through mid-fall and had many emerge after incubation, though they can be weaker.
4. Correct humidity levels. We believe this is more important for developing leafcutter bees than mason bees. Humidity levels during incubation should be between 35-80%.