Probably not!
If you have a bright window, you can probably grow microgreens without a grow light. We designed our reusable grow trays to fit on most windowsills to make it easy to grow microgreens without a grow light.
The amount of light and warmth available on a windowsill varies. The two main factors are exposure (which direction the window is facing) and season.
Variations by exposure:
- South facing windows receive the most direct sunlight
- East facing windows receive direct sunlight in the morning
- West facing windows receive direct sunlight in the afternoon / evening
- North facing windows receive indirect sunlight
Variations by season:
- Shorter days and cooler temperatures will slow growth and lower water requirements
- Longer days and warmer temperatures speed growth and increase water requirements
I've been growing microgreens on windowsills for years using our grow trays and wholeheartedly recommend giving it a try before investing in grow lights. Light from the sun is free and microgreens are a way of turning that free energy into food!