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Grow Lights for Seed Starting: Everything You Need to Know

starting seed under grow lights

Starting seeds indoors is a popular practice among gardeners, especially in regions with shorter growing seasons. One of the most crucial elements for successful seed starting is providing adequate light. This is where grow lights come into play. But with so many options available, how do you choose the right one? Let's explore the world of grow lights for seed starting.

Why Use Grow Lights for Seed Starting?

Natural sunlight is the best light source for plants. However, during late winter and early spring, the days are shorter, and sunlight can be scarce. Even the sunniest windowsill might not provide enough light for seedlings. Without sufficient light, seedlings can become leggy and weak. Grow lights offer a solution by mimicking the beneficial wavelengths of sunlight, ensuring seedlings get the light they need for robust growth.

Types of Grow Lights

  1. Fluorescent Lights: These are traditional choices for seed starting. They're affordable and effective, especially when using tubes designed for plant growth.

  2. LED Bulbs: LEDs are energy-efficient and have a longer lifespan than fluorescents. They can provide a full spectrum of light, making them ideal for all growth stages.

  3. Incandescent Lamps: Less common and less energy-efficient, these are not typically the first choice for seed starting but can be used in combination with other light sources.

Light Color and Intensity

Plants use different light spectrums at various growth stages. For seedlings, blue and blue-green light is essential, promoting strong roots and compact growth. As plants mature and move towards flowering, red light becomes more critical. Many grow lights offer a balanced light spectrum, suitable for seed starting and growing leafy greens.

Light intensity, measured in PPF (photosynthetic photon flux) or foot-candles, is another crucial factor. Seedlings require high light intensity for optimal growth. Ensure your chosen grow light provides adequate intensity, especially if you're growing in areas with minimal natural light.

Setting Up Your Grow Lights

Position your grow lights directly above the seedlings to prevent them from stretching towards the light. Adjustable setups, where you can raise the lights as plants grow, are ideal. Seedlings typically require 14-16 hours of light daily. Using an outlet timer can help automate the on-off cycle, ensuring consistent light exposure.


  • What type of grow light is best for seed starting? LED bulbs or fluorescent lights designed for plant growth are commonly recommended for seed starting.

  • Should you use a grow light when germinating seeds? While some seeds benefit from light to germinate, most seeds primarily need warmth. Once they sprout, light becomes crucial.

  • How long do you leave grow lights on when starting seeds? Typically, 14-16 hours a day is recommended.

  • What lights are best for seedling stage? Blue and blue-green spectrum lights are best for seedlings.

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