Mimicking the Sun – Indoor Grow Lights
When the summer is at its hottest or the winter it’s coldest, growing in a basement, garage, or barn may mean you have much more specific control of the temperature. You also may choose to grow indoors for ease of system access, security or lack of other space. When growing inside, you are playing mother and father nature and that goes for sunlight as well. Here’s what you need to know about the relationship between plants and the sun so you can choose and use the proper lighting for growing indoors. For a thorough run-down on all things lighting, please see our Grow Light FAQ.
Get Growing – plants grow most significantly when they can photosynthesize, meaning they need light to eat, drink and get bigger. Plants that don’t have enough light will be weak, thin and leggy, or short, squat and stunted.
Lighting Tip – Purchase the right lights for the plants that you are growing. Install your lights at the right height and spacing to provide adequate coverage to all your plants. Consider a light mover to help provide even coverage with fewer lights.
Sun Seasons – Summer solstice is the longest day of the year and Winter solstice
is the shortest, with day length varying by latitude. The spring and fall equinox are equal length day and night and often have similar temperature patterns.
Lighting Tip – Give your plants plenty of light. All plants that are vegetating, like leafy greens, the tops of root vegetables, and the first 30-60 days of growth, plants can consume 12-20 hours of light. Get a timer so you can easily and accurately manage your light schedule even when you are away from your system. Flowering and fruiting crops need 10-16 hours depending on the variety to complete their lifecycle.
Handling Heat – Plants determine the season by day length (photoperiod), light spectrum and temperature. When plants are too cold or too hot, they can go into “thermal dormancy” and won’t germinate properly or may not grow well. Some need to be completely dark to germinate, others need to see the light.
Lighting Tip – Some types of lights like Metal Halide or High Pressure Sodium can produce a significant amount of heat, and not all plants can tolerate the higher temperatures. If your plants are getting heat stressed, showing burning or crispy leaves, then it is time to move the light higher, remove heat with proper venting and air exchange and encourage air movement with circulation fans.
Sun Color – The sun has a broad spectrum of color
that varies throughout the day (think of sunrise/sunset, cloudy days and high noon). Light varies throughout the
year, think of the warming light of spring, bright white light in the middle of summer, rosy glow in the autumn and crisp to grey light of winter.
Lighting Tip – Choose the right light fixture and bulbs for the plants that you want to grow. Vegetative plants like the blue spectrum of light and flowering/fruiting crops like the red spectrum. Full spectrum light bulbs offer a broad range of light color. Some of the newest and well designed LED lights like the BlackDog LEDs offer a great color and light intensity for exceptional plant growth.
Light Intensity – 
Sunlight is not always the same level, sometimes it’s bright, sometime cloudy, low in the sky or high above head. The point is that sunlight varies.
Lighting Tip – Unfortunately light bulbs are on or off (most grow lights won’t work with dimmers). Grow lights diminish in light value over time, except LEDs. Even if you can see the light, the light quality can be reduced enough, that the plants can no longer absorb it, and therefore the lights are consuming electricity without providing much photosynthetic value to the plant. Replace light bulbs when the number of light hours has elapsed (based on the number of days they are shining X the number of hours they are on). You can also use a PAR meter to measure light value and compare that to the needs of the plant that you are growing.
The sun isn’t free when you consider all the factors discussed above (temperature, photoperiod, daylength, etc). Grow lights allow you to grow year round and increase growth production. It is valuable to know the initial purchase cost, energy consumption, bulb replacement cost, venting and other factors when determining the best light options for your growing conditions. Indoor lighting is a science all its own. The more that you can do to mimic the sun while extending your growing capabilities, the better your plants will respond.
