Plant Starting Light System


Like a lot of gardeners I start some of my seeds inside. This allows me to set plants outside once the weather is warm enough.   I grow a lot of different varieties of some of my vegetables and many of the varieties I want to plant are difficult to find and expensive.  Since I only plant relatively few seeds out of each packet, I save the excess for future years. (Seed Storage)

The key to starting seeds indoors is to have enough light. If you have too little light the plants will be tall and spindly.  For a number of years I used 40” fluorescent shop light fixtures, a common solution for gardeners.  I used two fixtures each holding two 40 watt tubes.  Last year I got one of those devices you can use for measuring how much power electronic devices are using.  Naturally I had to take a look at how much my lights were costing me to run.  I found the fixtures were using about 130 watts each. Only 80 watts were used by a set of bulbs, so the rest was being wasted by the ballast.

My lights were about 20 years old, and newer ones are almost certainly more efficient, but I decided to try another method. I decided to use compact fluorescent lights (CFL).  A local hardware store was having a sale, which influenced my decision. They had rebates on CFL bulbs, so they only cost me $1 each.

Six 100W equivalent bulbs seemed like a good number for my seed starting area that holds 4 standard size flats.   I get a lot more light than before and use less electricity than before. It costs about 2 cents/day to run.

To start, I put a board down the center of the plant starting shelf I built when I moved to this house.  Electrical junction boxes were mounted on the boards, and light sockets  to them.  The picture shows 3 light fixtures. Three more light bulbs are on the other side of the board. 

They were wired up on two separate circuits. The three CFLs (two front, one rear) on the right are on one circuit and the three on the left are on the other.  This lets me only light up half of the lights.  Although my shelf can handle four flats, I often only have one or two going at the start and end of the time I have the plants indoors.  I don’t need to run all the lights for one or two flats like I did with the shop lights.  I use a time clock to turn the lights on and off each day. The seedlings get about 14 hours per day.

Plant lights

CFL plant starting light system

One problem is that the CFL’s don’t have reflectors like the shop lights do. I put aluminum foil above the lights to reflect light back down. White paper covers the back wall and the sides of the shelf to reflect more light. There is also a piece of white cardboard that clips on the front. Besides reflecting light back in towards the plants, the front and side panels  help keep the plants a bit warmer as well as keeping curious cats away from the plants.

Based on energy cost calculations I think my new light system paid for itself in the first year.  Part of that was reduced energy consumption along with the CFL rebates and being able to turn off half the lights for part of the 2 ½ - 3 months  of the year the lights are used.

I was concerned about not having the proper mix of light wave lengths with the CFL bulbs.  I used two cool light bulbs along with the regular ones.  The  cool light bulbs have a bit of a blue tint compared to the regular ones. Plants need blue and red light.  Green light is reflected off the plants (that’s why they look green) and is of no benefit.  

I have been augmenting part of the area with LEDs based on some LED experimention I have been doing.  I added some LED lighting with red and blue LEDs.  These are used with the CFL lights. If I turn off the CFL  lights the plants have a strange purple coloration.  I think that the LEDs helped. The tomato plants seemed less leggy than in the past.  I need to build on to the system, but it probably won't happen this season. 

New LED bulbs are available for reasonable prices. As the CFL bulbs get dim or burn out I have been replacing them with LED bulbs. I doubt I will  have to replace them again.

Overall, I am very pleased with this set up. The plants are doing better than the old system and it is saving money on the electricity bill.


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