When I first started growing my own transplants, I did it without supplemental lighting. That first spring, I moved flats of seedlings around our apartment to catch the intense rays of sunlight that beat through our high, wide southwest-facing windows. Even without knowing that the windows were tinted with something that blocked supposedly detrimental rays, you know that this is a ridiculous way to grow plants! Despite my time-consuming efforts to keep the seedlings in a ray of sunshine, the intensity and length of light always kept the little things reaching for more and, while they were, eventually, transplanted into the container garden on the balconey, they never did come to much because of their initial rough start in life.
The next spring wasn’t much better. Although I did use supplemental lighting, it was one of those little incandescent-like bulbs marketed as a grow light. I screwed it into a decorative lamp with a shade, clustered my flats around it, and was once again rewarded with spindly, anemic seedlings reaching for light that was too far above their heads.
By the third spring, I’d learned my lesson. Unwilling to shell out +$500 for a seed starting shelving unit with ‘growlights’, I did my research and found out that most people had success with a simple and fairly inexpensive shoplight fitted with one warm flourescent bulb and one cool flourescent bulb. So, choosing the brightest, warmest room in the house (we’d purchased a home by that point), which was my office, I had my husband construct some durable floating shelves to which he secured two shoplights. Each shoplight got a cool bulb and a warm bulb, and each shoplight was plugged into a timer set to stay on for 17 hours a day. Once the seeds germinated, the plastic used to keep the soil from drying out was whisked off, and the trays were nestled under the lights.
No more spindly, anemic seedlings reaching for the light. The warm and cool bulbs mimicked closely enough the color range of real sunlight to result in bright green leaves. Keeping the bulbs only a couple of inches above the plants meant they could bask in light, not stretch to seek it out. By the time the transplants were ready to go into the garden, they were bushy, stocky, robust specimens that grew and produced abundantly, and I’ve never done it any differently since then.
This year, though, after selling all my seed starting equipment before we moved back to Canada, I needed to re-stock. As you can read here, I decided on a free-standing shelving unit because we rent and I wanted to limit the amount of holes we’d have to patch when we move. But I chose the shelving for a couple of other reasons: the shelves are adjustable so I can set them fairly high and have plenty of space to adjust the shoplight heights in order to keep them only a couple of inches from the seedlings at all times; and the shelves are metal mesh, allowing me to slip an S-hook through and attach the lights using a chain, adjusting the height of the lights by slipping the chain link up or down on the S-hook. (It is important to me to be able to easily remove the shoplights from the shelving because, during the off-season, the shelving will be used for other things besides growing plant starts.)
I have attached two 4 foot long shoplights to the shelf – hopefully, that will be enough to cover all the plants – and have outfitted each light with a warm bulb and a cool bulb. However, due to the fact that I only bought one light fixture the first time and when I went back to buy a second fixture, they were sold out and I had to go to another place to buy the second fixture, my shoplights hold different sized bulbs – T12 in one, a supposedly cheaper but less efficient bulb than the T8 I have in the other light fixture. (For an excellent explanation of bulb choice, I suggest going to The Far North blog and reading her post about lighting.)
The shoplights are plugged into a single timer that stays on for a little over 16 hours. Supplemental lights need to stay on longer than the sun would shine because they don’t emit the same quality of light as sunshine – think of it as the same thing as eating a complete diet of vitamin tablets versus eating whole foods.
So that’s the lighting set-up – about $40 in materials, a nominal sum for electricity, and no more light-deprived seedlings.