Grow lights: Creating an artificial spring

As I look outside this morning all I see is white. We just had a light snowstorm, and it looks like we are back to winter.

However in my basement it’s a different story. I’m starting to clean up the two seedling grow beds, and I’ll be powering up the lights in about a week. That’s the first real sign of spring for me — planting the first seeds (probably broccoli).

I’ve been growing seedlings indoors under grow lights for over 20 years, starting out with the technology that was common at the time — T12 fluorescent bulbs in a 4-bulb, 4-foor-long bank. It’s basically the same lighting that you see in industrial buildings and offices. It’s cheap and it works OK, especially if you buy the slightly more expensive full spectrum bulbs that are intended for seedlings.

Nowadays, the technology of grow lights is vastly improved and getting better every year. The lighting options are so expansive it’s become confusing to figure out what works best. Also, the price range is just as expansive — from $20 up into the $1,000s.

I’ve settled on 2 different lighting sources that seem to work pretty well.

T8 Fluorescents

I have 2 seedling beds. One of them, which is about 10 square feet, uses T8 fluorescent bulbs. This system is readily available and fairly inexpensive. You can buy the bulbs and the fixture at hardware stores or big box stores like Home Depot.

These bulbs are slightly smaller than T12s, but they put out a lot more useful light, and I think a slight amount of heat. That’s important for my situation, as I’m growing in a dark and unfinished 250-year-old basement where the natural temperature hovers in the mid 50s.

I need to generate heat in order to get to the 65 to 70 germination range, so I have 2 ways to do that — I have enclosed the seedling bed in glass and wood and insulated it, and I use a heat mat to get the seedlings going. I’ve found it’s vital to remove the mat once the seedlings have sprouted. I’m able to get the temperature up to a steady 65 to 70.

One other reason why I have a sealed seedling bed is mice. In my first year of growing in the basement, I was chagrined to discover that my seedlings were the basis of the resident mice diet. They are very hard to keep out of the seedlings, but after a lot of work I think I’ve managed to seal the beds.

A couple of other things I do — I have a small fan inside the seedling bed that’s on a timer. It blows onto the seedlings for about 12 hours a day. I move it around every few days to change the direction of the “wind.” I’ve found that this greatly strengthens the seedling stems. I also have the lights on a timer, keeping them on for about 18 hours a day. It’s important to give the plants a few hours of “sleep” time.

I’ve had incredibly good experience with these lights and my overall setup. Seedlings sprout in half the time (and sometimes less) than the norm.

LED lighting

LEDs are a more sophisticated way to light your seedling bed. They come in a dizzying variety of brands, sizes, price ranges, and capabilities. I bought 2 different lights, both in the 40 watt range which I’ve since discovered is a little too low. They tend to effectively light about 4 to 6 square feet apiece, which is not quite adequate for this seedling bed. It’s about 15 square feet.

One of the LED lights is better than the other, so I think I’ll either augment the 2 existing lights with a higher wattage light, or replace the inferior light.

There are dozens of videos on YouTube reviewing grow lights. I’ve watched quite a few of them and the consensus is, there is no consensus. I think each situation is unique, and so you have to hunt around and experiment to find the best lighting source for your peculiar situation..

I’d say that overall, the LED lights are inferior to the performance of T8 fluorescents. They are able to maintain a slow growth of the seedlings that I started under the T8 lights, but they just don’t quite get the job done.

John Macone owns and operates Farmer John’s Organic Farmstand, a neighborhood farmstand in Amesbury, Mass.

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