As I sit here in bed (where I do about 98% of my writing) looking out the window at the winter wonderland, it’s hard to believe that spring will ever come. I’m not in a rush (yet), and I’m not complaining; this area has been in a serious drought for years. We’ve been praying for snow all season and we keep praying for it even as we have an additional 4-7 inches in the forecast over the next 36 hours. But I’ve got at least 18” of the white stuff covering my back yard and my 42” retaining wall has completely disappeared. Right now I’m not too confident about seeing the soil before April 1. My time might actually be better spent planning the garden than starting the seeds.
Still, I can’t help myself. Especially as the produce prices continue to shoot through the roof. I have to make sure that my garden is as productive as possible. The first step is calculating when exactly to start seeds, as was covered in December. Then after sowing the seeds, the next step is making sure they don’t get leggy.
I thought I was pretty well versed in what caused legginess and how to prevent it, but I decided to watch a YouTube on the topic anyway, and I learned about two more causes of legginess that I’d been unaware of. And I thought the whole topic would be a good one to cover.
Leggy seedlings—those tall, spindly little sprouts—are stressed seedlings. Seedlings become leggy for a number of reasons.
The most common one involves lighting. Seedlings should receive at least 12 hours of light per day. Sixteen hours is better, especially when using artificial light and growing indoors. Keep in mind that even a really bright, south-facing window may not yield adequate light. This is because so many of the modern windows in our energy-efficient homes are manufactured to prevent some heat and light from passing through. Even though we think we’re getting plenty of light through those windows, the seedlings say otherwise when they stretch to reach the light.
Artificial lighting usually yields better results—stronger seedlings—than what we can get growing in a sunny window. But even artificial lights aren’t fool-proof. You’ve got to use the right kind of light. Compact fluorescent (CFL) and LED lights are best. There should be a minimum of 2000 lumens per fixture of blue spectrum light—daylight white—in around the 6500K range. In addition, the lights should be turned on before the seeds germinate, and they need to be the right distance above the seeds. Most of the less expensive fluorescent lights need to be 2-3” above the seedlings—close enough that the seedlings don’t stretch to reach the light, and far enough away that the lights don’t burn the seedlings. Also keep in mind that fluorescent lights need to be replaced every few years, even if they haven’t burned out.
Next, (and this is one that was totally new to me), don’t use a heating mat too long. Once the seeds have germinated, it’s time to remove the heating mat. While many seeds germinate best at higher temperatures, they grow best at lower temperatures, like around 65-70°F.
In addition, don’t let the soil dry out, as this also contributes to legginess.
Another reason seedlings become leggy is that they are overcrowded. If seedlings are competing for nutrients as well as light and water, they will grow taller in order to get that most important nutrient of all, Vitamin Sun.
And finally, seedlings become leggy because they lack the wind to help them build strong stems. The easiest way to mimic the wind is to place a fan so that it blows across the tops of the seedlings. If a fan can’t be arranged, then brushing the tops of the plants with the hands several times each day will also work very well.
What if, despite take all these precautions, you still end up with some leggy plants? Most of the time it’s going to be better to just start over with new seed. If, however, seed is precious and can’t be easily replaced, there are some plants that will do well enough in the garden.
Tomatoes have adventitious roots—all those little hairs poking out from the tomato stem will become roots if planted in soil and given water. While peppers and eggplants do not have adventitious roots, they can still grow and produce pretty well if planted deeper in the soil. Broccoli and cabbage may also yield well.
Watering from below and that fan are also good for preventing damping off.
ReplyDeleteI try to plant only two seeds per soil block as far apart as I can so if they are both successful, I can carefully split the block to replant.
Timing of the heating pad is something I'd not thought of thanks Jennfer.
Do you have a suggestion to a good value heating pad?
Michael,
DeleteI'm sorry to be so slow responding. Life has been crazy this week--nothing horrendous, but 2/3 of the people living here, and actually two of the kids who don't live at home currently, will be pretty cranky if this week gets repeated any time soon. Becky is wondering what she did to offend the karma gods.
Anyway, I don't have any suggestions for a heat mat. I've been thinking of getting one for the first time. But I'm also thinking I might just try starting the peppers on the mantle. I think it will be warm enough up there, and I've never had any problem with tomatoes.
I also always try to separate the block if I get more than one seed to germinate. I try to tell myself that it's not like I'm killing kittens when I thin out seedlings, but I'm rarely successful.