Greenhouses capture natural sunlight, but natural light isn’t always enough. In winter, short days (8–10 hours of weak light) mean fruiting crops like tomatoes and peppers simply can’t produce. Seedlings stretch and weaken. Even hardy greens slow their growth dramatically. Supplemental LED grow lights bridge the gap, providing the additional photons and extended photoperiod your plants need during the darkest months.
You’ll benefit most from grow lights if you’re starting seeds in late winter, growing fruiting crops through winter, cultivating herbs year-round, or propagating cuttings. If you only grow cold-hardy greens and your greenhouse gets 6+ hours of winter sun, you may not need supplemental lighting at all.
An outstanding entry point into quality grow lighting. Samsung LM301B diodes are the industry standard for efficiency and longevity. The fanless design means silent operation—important if your greenhouse is near living areas. Dimmable output lets you match light intensity to plant stage. Covers a single bench or seed-starting area perfectly.
The bar-style form factor distributes light more evenly than square panels, which matters in a greenhouse where you’re supplementing natural light rather than replacing it entirely. The enhanced red spectrum supports flowering and fruiting. At 300W, it covers a significant greenhouse bench area. Well-proven and well-reviewed.
The budget-friendly approach to greenhouse supplemental lighting. These T5-style LED strips link together in a daisy chain, letting you run a continuous light bar across your bench. The 6500K daylight spectrum is ideal for seedlings and leafy greens. Mount 6–12 inches above seed trays for optimal results.
The premium option for growers who want precise control and maximum efficiency. The IONFRAME EVO4 delivers uniform coverage across a full 4×4-foot area with smart app control for scheduling and dimming. UV and IR supplementation support plant development beyond the visible spectrum. Moisture-resistant driver coating is a thoughtful touch for greenhouse environments.
The simplest possible supplemental lighting solution. Screw it into any standard lamp socket and point it at your plants. The full-spectrum white light works well for seed starting and maintaining herbs through winter. Won’t replace a dedicated grow light for serious production, but it’s an excellent low-commitment starting point.
Full spectrum (white light) is the standard for modern LED grow lights. It includes the blue, green, and red wavelengths that plants use for photosynthesis, plus additional wavelengths that support overall plant health. This is what you want for greenhouse supplementation.
Enhanced red models add extra output in the 620–660nm range, which promotes flowering and fruiting. Useful if you’re growing tomatoes, peppers, or strawberries through winter.
UV and far-red supplementation is available on premium models. UV can enhance flavoring compounds and essential oils in herbs, while far-red promotes stem elongation and can trigger flowering responses in certain species.
In a greenhouse, grow lights supplement natural sunlight rather than replacing it. Mount lights 12–24 inches above plant canopy (higher for more powerful fixtures, lower for T5 strips). Run lights to extend the total photoperiod to 14–16 hours for fruiting crops, or 12–14 hours for greens and herbs. A simple outlet timer or smart plug handles scheduling automatically.