42-Watt Barrina 4′ LED Grow Light (6-pack)
Insufficient light is the number one reason that people fail at starting plants from seeds. They buy fresh seeds, use the correct seed starting medium, provide sufficient water, and before you know it, the seeds have germinated and they think they’re off to the races. After only a few days, their plants start to become leggy as they try to reach toward whatever light source is available. Eventually the fledgling seedlings fall over into the soil as they continue their unbalanced growth and eventually die. Those that don’t die at this stage will die when you transplant them, as they haven’t developed a strong root structure.
As most amateur gardeners don’t have a greenhouse, many rely on a sunny window or kitchen counter to grow out their new seedlings. While these locations are fine for mature houseplants, they simply cannot provide the minimum 14 hours of high quality light that new seedlings need to get them where they need to be by the time it’s ready to set them out in the garden.
Enter the game-changing world of LED lighting, specifically the Barrina 42W LED grow light. I purchased 12 of these my first year to start plants for my new market garden business and have bought a couple more sets since. I clipped them to the shelves (two lights per 4′ shelf) of a rolling wire utility rack using S-hooks and a light-duty linked chain from Lowe’s.
Your lights should be no further than about three to four inches above the trays for both germination and once your seedlings have emerged. I see lots of pictures and videos online of people with their grow lights that are not close enough. If your seedlings start to get leggy or spindly, it’s a sign that they aren’t getting enough light. Apart from tomatoes, which can be buried deeply and send out new roots, most vegetables never recover from this. You end up with weak and stressed transplants that can’t support themselves in the garden and will be much more susceptible to disease.
I keep my Barrina lights on continuously until the seedlings get their first set of true leaves. At that point, I keep them on a 18-hour-on, 6-hour-off cycle until I am ready to harden them off by setting them outside in a location protected from sunlight and wind for a couple of hours per day.
You could easily fit three on a standard width wire rack shelf and probably get slightly faster and more vigorous growth, but I consider two per shelf more than adequate provided the distance from the seed tray to the lights is appropriate.
These lights deliver only the wavelengths that the plants can actually use, so your plants are receiving an intense bath of light and still only using 42 watts per hour per unit. Unlike fluorescent tube lights, these should easily last over 15,000 hours.
My favorite thing about these lights other than the ridiculously low price per watt is the ability to daisy chain them together. I zip-tied a 12-outlet electrical outlet strip to one of the rear vertical tubes of my rolling shelving unit and plugged each light directly into this. Even with two lights per shelf with four shelves, I still have four outlets open for my seedling heat mats (insert link here).