"Here Comes The Sun!"

I've had the subject of light in mind for the last few days.  Maybe because we just turned the clocks back, maybe because having the sun out on these fall mornings is particularly magnificent.  So many uses of the word light! One can see it - like an epiphany - or let it shine, turn it on, measure it, hide it. But we all need it to thrive. Which brings me to indoor gardening. What kind of light for our indoor gardens?  And where do we find it?


Home Depot has AISLES of halogen lumen daylight compact fluorescent incandescent T12 watts LED HID lights.  HUNDREDS of lights.  I'll resist making the pun and shed some on the subject of indoor growing.  

The first picture shows the full spectrum of color in sunlight.  The second shows what plants need for proper growth and development.

Most grow lights are either "full-spectrum" or "daylight" with a broad spectrum range like real sunlight.  Other lights have more blue frequencies ("cool") or more red frequencies ("warm"). 

Plants use either blue or red light at different stages of their development.  Seedlings and leafy parts use the blue and violet range, while flowering or fruiting stages use more red/orange light. 




Depending on what we are growing, we'll use either existing sunlight, lights that emulate the sun (like fluorescent full-spectrum lights), or additional blues/reds in more intensive lighting if the plants we're growing need more of that color. 

I think it's interesting that the seasons have different kinds of light too.  Springtime has bluer light, which corresponds to beginning growth and vegetative growth.  By the end of summer there's alot more of the oranges and reds in sunlight, which corresponds to the ripening, flowering and fruiting that takes place.

The combination of all of the colors in light at any given moment will give off a certain color temperature, measured in Kelvins (K).

Lumens refer to the amount of light the human eye can see.  It isn't the best way to measure light for growing plants because plants use light for photosynthesis, using more color in the red and blue ranges.  (We see the yellow and green ranges). 

So on most lights in the store you'll see measurements in lumens, Kelvin and color temperature (cool or warm, or daylight for example).  The package will indicate if it's fluorescent (with it's different sizes like T8 or T12 or Compact).  Then there's HID (High Intensity Discharge - extremely bright) and LED (Light Emitting Diodes).  That's some serious growing.

What is the best? For general growing purposes, fluorescent full-spectrum lights - either the tube shape or compact like a bulb are used.  These lights will help you grow cool weather vegetables like the spinach, lettuce and greens that we're starting out with.  Certain fixtures are needed for these. Both are relatively inexpensive and will get you growing right away.  Depending on the light available, one or two T8 fluorescent grow lights will be adequate for these purposes.  Other stronger grow lights will be needed for fruiting or flowering vegetables.  More specifics to come...

Take a look at these other handouts before we get into planting....and growing!  Until then, think green...and dream. 

                                              

              
                   Live in rooms full of light. ~Cornelius Celsus