don’t skimp on light when starting seeds
STARTING SEEDS is not hard…unless you skimp on light, or your timing is off. Sorry, friends, but your windowsills just won’t do, and over-eager “headstarts” usually result in past-their-prime seedlings.
For the timing, consult my Seed-Starting Calculator, customizable to your own location according to final frost date. But first…
I recommend investing in a reflective hood that houses high-output fluorescent tubes called T5’s, or T5 HO’s. I can’t wait until LEDs for seed-starting get a little farther along in development, and the prices come way down, since LEDs will put out even more light with less heat. (But good news there: It’s progressing fast, and there are even LED tubes engineered to fit into our T5 hoods, so only the bulbs will need replacing.) Meantime, T5’s are a big step up from old-style fluorescents, which I have stopped using–providing up to eight times the light (more energy efficiently, too).
How many flats will you have under lights at any one time? Remember: No need for supplemental light before seeds sprout, and once weather begins to stabilize, you can carry seedlings out by day to enjoy natural light, as I do. That produces stronger plants; the illustration (with data from plant physiologist Dr. Thomas Bjorkman of Cornell) shows why, since no artificial lights can match nature, even on a cloudy spring day. It also saves lighted space indoors.
My biggest gridlock is late April, when my cool-season crops (like some Brassicas) are in their last week or two inside, and my warm-season ones (like tomatoes) have just sprouted, needing light as well. Nevertheless, I get by with lights to accommodate about three flats at any time—again, because I move things outside to a sheltered bright spot on stable weather days. Standard commercial seedling flats are 21×11 inches, if that helps the calculation of how much hood you need; many home garden seed-starting “kits” have a slightly smaller footprint.
Rather than one big hood, I have two smaller ones–one suspending a 4-bulbs T5 reflective hood that holds a single flat (above), and another for two flats. The modular arrangement allows me to economize on energy use when I only have one flat going.
Important note: Many hoods do not come with a “stand”–or with height-adjusting hardware, to keep lights close to growing plants. Use chain and S-hooks, for example, or special pulley-like hardware made for the purpose and used in hydroponics; some carpentry skills required. Examples of hoods for one to four flats, requiring a little carpentry and not, are featured at this link.
more help with seed-starting
- All my seed-starting gear
- 18 confidence-building tips for seed-starting
- Why seedlings stretch and get spindly
- My seed-starting calculator for vegetables, flowers, herbs
(Disclosure: Purchases from Amazon affiliate links yield a small commission.)