Artificially lit crops pollination advice

As bumblebees rely on sufficient daylight, artificial lighting can be used to ensure good pollination conditions. As bumblebee may face orientation problems when insufficient daylight occurs (particularly 4 to 10 weeks before or after the shortest day, depending on latitude and environment) rapid decline in colonies could occur. In the ever-evolving world of agriculture, the utilization of artificial lighting has revolutionized crop cultivation by extending daylight hours and enabling year-round production. However, with this technological advancement comes the critical challenge of ensuring efficient pollination in indoor settings.

While outdoor pollination is often facilitated by natural agents like wind and insects, artificially lit crops necessitate careful consideration and deliberate interventions to achieve optimal pollination rates. In this article, we will delve into the unique aspects of pollination in indoor environments and provide valuable advice on how to overcome potential obstacles. From understanding the role of various pollination methods to implementing smart strategies for attracting pollinators, we aim to equip you with the knowledge and insights essential for successful pollination in your artificially lit crops.

Tips for pollination in artifically lit crops

Introducing the Wireless Beehome-System (WBH)

To counteract daylight-related issues we advise the installation of our Wireless Beehome-System (WBH). With the WBH-system, growers can enable bumblebees to fly during periods of adequate daylight. On average, bumblebees are allowed to fly between 10:00 a.m. and 2:00 p.m. (4 weeks before/after the shortest day), with an additional half-hour per week. For optimal pollination duration, you can connect the WBH-system to your climate computer to measure actual light intensity.

Placement advice in artificially lit crops

For best results, consider the following placement advice in greenhouses with artificial lighting:

  • In regions with higher latitudes (Scandinavia - Northern Europe), place bumblebee hives high in or above the crops starting from week 40 (+4) until week 10 (-4).
  • Position the colonies to receive direct and early daylight
  • Provide shade for colonies during intense sunlight between 11:00 a.m. and 3:00 p.m., especially during autumn and early spring
  • Ensure early daylight is not obstructed by side screens, polycarbonate side walls, or other filters.
  • Between week 6-10, switch back to normal bumblebee hive allocation based on latitude.

Snow during pollination

How to pollinate during snow? During snowfall, orientation is seriously disturbed as snow reflects 90% of UV-light. When snow covers the greenhouse, it acts as an effective UV filter, affecting pollination. Monitor pollination and consider introducing extra bumblebee hives or carrying out temporary hand pollination when natural pollination is insufficient. Remove snow from the greenhouse roof when possible.

Energy screens and grow lights

The use of energy screens in artificially lit greenhouses can lead to reduced light levels, affecting bumblebee navigation. To counter this, synchronize the opening of bumblebee hives with the energy screen and daylight cycle, allowing the bees to fly only when there is sufficient daylight (e.g., between 10:00 a.m. and 3:00 p.m.). If the energy screen remains closed for a full day, it's better to close the hives as well. Bumblebees can fly and forage under artificial lighting but may struggle to orient themselves and return to the hives in an environment solely illuminated by artificial lights.

Grow light impact on pollination

Using grow lights, especially during winter to extend daytime for plants, can lead to issues for bumblebees. Grow lights emit the light spectrum relevant for plant growth and development (400-700nm) but lack the UV spectrum necessary for bumblebee orientation. Moreover, the heat from the lamps can damage bumblebee wings while flying to the lights, and multiple light sources can cause confusion in their orientation.

To prevent bumblebees from flying aimlessly in the crop, it is advised to turn off grow lights well before sunset to encourage their return to the hive.

LED lights and pollination

Based on experiences with LED lights in Dutch greenhouses since 2008, no problems comparable to regular artificial lighting have been observed. Therefore, using red and blue LED lights doesn't require the Wireless Bee Home (WBH).