Best Grow Lights for Indoor Plants
Even the sunniest windowsill supplies only a fraction of the light plants receive outdoors. Supplemental grow lights help houseplants stay compact and healthy during winter and allow you to grow light‑loving varieties in darker rooms, according to the University of Minnesota Extension’s lighting guide. Understanding bulb types, light quality and placement will ensure your plants thrive.
Grow light types
| Bulb type | Pros | Cons | Suitable for |
|---|---|---|---|
| LED (light‑emitting diode) | Energy efficient, long‑lasting, broad spectrum and cool running | Higher upfront cost; very bright light can be distracting | All houseplants; ideal for multi‑tier shelves |
| Fluorescent | Moderately energy efficient, lower initial cost, available in full‑spectrum options | Shorter lifespan and higher energy use than LEDs | Seedlings, leafy greens and low‑light plants |
| Incandescent | Low purchase price | Inefficient, produce heat, short lifespan and high far‑red light causing stretch | Supplemental accent lighting only |
| High‑pressure sodium/metal halide | Emit strong light over a wide area | Best suited to commercial setups; heavy, produce heat, older technology | Greenhouse use and large collections |
Choosing the right light
- Spectrum: Plants use primarily red and blue wavelengths for photosynthesis. Blue or mixed bulbs support leaf growth, while red or mixed bulbs encourage flowering. Full‑spectrum or white LED fixtures cover the needs of most houseplants.
- Intensity: Maintain appropriate distance between bulbs and foliage to avoid heat damage. As a rule of thumb, keep LED or fluorescent lights 12–24 inches above foliage plants and 6–12 inches above flowering plants.
- Duration: Houseplants benefit from 12–14 hours of light per day; flowering varieties may need up to 16 hours. Use a timer to ensure consistent photoperiods.
- Colour temperature (CCT) and CRI: For seed starting and foliage growth, select bulbs with a CCT around 6,500 K and a Colour Rendering Index above 85, indicating a balanced spectrum similar to daylight.
The pros, cons and placement guidelines summarised above are drawn from the University of Minnesota Extension’s lighting for indoor plants and starting seeds guide, which offers a comprehensive overview of bulb types and light requirements for common houseplants.
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