As we have discussed in Parts 1 and 2 of Seed Starting 101, providing the right amount of light for your seeds can be a daunting task. The number of footcandles on an average summer day outside is around 25000 whereas the number of footcandles in a well-lit office drops dramatically to 125. In case you aren’t aware, footcandle is a way to measure light intensity. So what type of lighting should you use to get your seeds off to the best start?
It all depends on what you want from your seed starting adventure. If you are interested in just getting them large enough to put in a cold frame, a set or two of fluorescent shop lights will serve you well. If you want to move up the sophistication chain, consider LED (light emitting diode)lighting. LED lights are very energy efficient and last forever. OK, not forever but it will seem that way in comparison. These are the same lights that the new stoplights are composed of. They will provide ample light for your seeds; the only drawback is that they are more expensive initially. You can pick up a set of shop lights for around $25 whereas a small LED light will cost a couple of hundred dollars. You can probably find a better price by shopping around online but even still, it won’t be $25.
The grandaddy of all the lighting systems is the metal halide light. But again, the cost of the lighting is prohibitive to the average gardener. Costing upwards of $500 each, I won’t bother to expand more on this lighting. If you choose to go with flourescent shop lights, what can you do to get the most light out of them for your seedlings?
- Replace your light bulbs each year. The light quality diminishes each year and for a $10 investment, you can ensure that your seedlings are off to the best start.
- Use warm and cool bulbs in your fixtures. Plants need a combination of wave lengths to do their best and that’s what your aiming for.
- Keep your lights within inches of your seedlings…not 12″ or 8″; hang them 1″-2″ above the tallest seedlings and adjust them upwards as the seedlings grow.
- Leave your lights on for 16 hours each day. Mine are actually programmed for 17 hours right now and the plants will be fine. What you don’t want to do is leave them on 24/7. Plants need to sleep too (this is when the process of respiration takes place).
- Aluminum foil. This may sound like a bizarre solution but it works. It helps immensely for those poor little seedlings on the outside edge of the flats. They are the ones that lean in to try to reach the light in the center. By draping aluminum foil over the lights so that it touches the table on both sides, it creates a more reflective environment and also keeps the heat in. I leave the ends open so that air can still circulate.
I’d love to hear the creative ideas that other Mid-Atlantic Gardening readers have for increasing the light that your seeds receive. Leave me a comment below or e-mail me at firstname.lastname@example.org. Click here for Part 4 of Seed Starting 101. Happy gardening!