Give seedlings a head start with good lighting

Starting seeds indoors is an excellent way to get a head start on the spring garden. But even with ample south-facing windows, it can be difficult to give seedlings the sunlight they need for quick, robust growth. And without sufficient light, seedlings will grow tall and spindly, with weak stems. These are not good candidates for transplanting into the garden.

An easy, practical alternative is to provide artificial light, using either a combination of cool and warm fluorescent bulbs or full-spectrum fluorescent bulbs. One advantage to fluorescents is that they provide cool light; incandescent bulbs give off too much heat, quickly drying the soil and air around the plants. Another advantage to fluorescents is that the light they emit includes the blue portion of the spectrum. Blue light is essential for low, stocky growth. Incandescent bulbs produce red light, which makes plants leggy.

As the distance from a fluorescent bulb increases, the intensity of the light the bulb emits diffuses rapidly. Seedlings require high light intensity, so it is important to place the lights close to the emerging plants — no more than three inches away from the leaves. Some experts recommend positioning the bulbs so that they are just not touching the plants.

Light is critically important to the seedlings but, like water and fertilizer, it’s possible to overdo it. Humans and other animals may be able to sleep with the lights on, but there are important functions that plants need to perform and can only perform in the absence of light. Give seedlings at least 12 hours of light a day, and up to 16 hours, but give them dark conditions for at least eight hours a day.

Do you need special plant lights? The experts say, “No.” Cool-white fluorescents are perfectly suitable and are less expensive than plant lights. Some reports indicate that the best light source is a combination of cool-white and warm-white fluorescents.

Since the light is weaker toward the ends of fluorescent bulbs, get the longest tubes you have space for, and cluster your plants toward the center. Also, keep the bulbs dust-free to get the most possible light.

You can buy plant stands or carts, or you can make your own. Here’s one idea. At stores like Home Depot, you can purchase metal shelf strips that attach to the wall and adjustable brackets that fit into slots on the wall strips. A system like this is easy on the pocketbook and easy to install. All you need is some free wall space that is at least five feet wide and tall enough to accommodate as many shelves and lights as you know you’ll need.

The shelf brackets come in different sizes; a larger size will give you more options for the depth of the shelves. Before purchasing, decide if you want to mount a single or a double fluorescent light fixture. A 12-inch bracket will just barely accommodate two light fixtures with some overlap. These cast enough light to illuminate a seed tray that is 10 inches deep.

Pre-laminated shelving is available and has some advantages, e.g., it’s impervious to water and it looks more attractive than old boards you may have on hand in the basement or garage.

When you’re not using the shelves for seedlings, you can use them for anything else you might need them for. Just remember that you’ll need to find another place for the books and knick-knacks when spring comes around again.

Pam Baxter is an avid organic vegetable gardener who lives in Kimberton. Direct e-mail to pamelacbaxter@gmail. com, or send mail to P.O. Box 80, Kimberton, PA 19442. Pam’s nature-themed books for children and families are available on Amazon, at Amazon.com/author/ pamelabaxter.