Maryland Grows

It’s February, so really time to think about starting plants from seed, if not necessarily time to actually start them. (If you are itching to get going, I wrote a post a while back about which seeds to sow in February. Hint: not tomatoes.) Let’s continue with the guide, which I hope you’re finding a practical help to this complicated subject. (Parts One and Two also available.)

Choosing Seeds

If you have not already impulsively ordered a bunch of seeds without concern for whether they’re the easiest ones to grow (in which case you are a person after my own heart), now is a good time to go shopping. In most cases these days that means shopping online. You can certainly buy seeds at garden centers and even supermarkets, though they may not be on display this early, but you get a much better selection by visiting the full catalog of a seed company website.

I’ve written a post about choosing a seed catalog to order from, so won’t repeat that information here. If you are confused by the jargon used in seed catalogs, Jon Traunfeld explains it in this post.

But which plants are best for novice seed-starters to grow from seed? First of all, you shouldn’t always let ease dictate what you choose to grow. If you like a vegetable (or a flower) and want to grow it, you may be willing to take on the challenges involved. Some seeds are more cooperative than others, however. Of the many veggies that are best started indoors, here are a few I recommend for beginners:

• Tomatoes. The favorite of many gardeners, they need to be started indoors (because there isn’t time for them to mature and fruit plentifully if started outdoors). They grow with alarming ease.
• Peppers. Not quite as easy as tomatoes, but that’s mostly about providing enough heat to make them germinate. More on that further down.
• Brassicas, especially kale, collards, broccoli, kohlrabi, and mustard. Of these, only broccoli really needs to be started indoors, but the others can benefit from a little head start before transplanting. I don’t advise starting your seed-starting journey with cauliflower or brussels sprouts, but that’s more about the difficulties faced growing them to maturity in the garden; they germinate and grow indoors just as easily as the rest of the brassica clan.

Many vegetables can and should be started directly in the ground outside, including all root crops, the cucurbits (squash, cucumbers, watermelons, etc.), beans and peas, and quick-growing greens like lettuce and spinach. You can start the last two indoors, and I sometimes start cucurbits that way, but if your space is limited there’s little point.

When to Plant Them

Picking the right week to put your seeds in the soil, whether indoors or out, can be confusing. We have all the information you need on the HGIC website. Basically, you should refer to the numbers on your seed packet (or in the catalog) to determine how many weeks before average last frost date to start the seeds, and do some counting backwards. My additional advice: err on the side of starting later rather than earlier, at least with heat-loving plants. This sounds contrary in the days of global warming, but our weather is getting increasingly wacky, not just warm. It isn’t merely that summer starts early, it’s that spring temperatures fluctuate, rain can be heavy, and frosts come out of nowhere. Seedlings planted into consistently warm and calmer weather (late May or later) will catch up fast, as compared to those that were planted out when the weather was iffy or held indoors under lights when they were bursting out of their pots. On the other hand, you might want to get your spring plants growing outdoors during our weird March heat waves, in preparation for an April chill. Honestly, we’re still trying to figure this out.

Germination Requirements

You’ve got the seeds; let’s make them grow! Here’s what seeds need to germinate:

• Warmth. Temperature needs vary for seeds to get going, but none of them like it cold. Spring plants, like lettuce and brassicas, don’t require more than a warmish room. Summer plants, however, are meant to germinate and grow in heat. If your seed-starting room doesn’t make you sweat, it may not be warm enough for tomato and pepper seeds. And what they really need is warm soil, anyway, not warm air. A seedling heat mat can make the difference. It fits under the tray, should be plugged in 24/7 (not on the light timer), and will warm up the soil (a.k.a. seed-starting mix). You can also get thermostats to control the temperature more exactly, if you are that sort of person. (Charts of optimal germination temperatures for different seeds can be found online.) After the plants start growing, they don’t need to be quite as warm, so take away the heat mat or lower the thermostat.

• Moisture. Once you’ve put a seed in soil and watered it, do not allow the soil to dry out, or the germination process will stall and probably fail. One way to help the soil stay moist is to cover the tray or container with a clear plastic dome. You can buy these to fit trays, or improvise your own for smaller containers out of recycled clamshells. Or you can put plastic wrap over the surface of the soil. Once the plants are growing, it’s better to remove the covers or else the soil may start sprouting mold.

• Light (or not). Some seeds require light to germinate and some prefer darkness (which can be found underground). Follow the instructions on the seed packet about how deep to plant the seed. If it says “sow on surface” don’t put soil over the tiny seeds!

Some seeds need more than this, but if you decide to grow (for example) okra or nasturtiums, you might want to look up scarification, and if you are hankering to grow yourself some native plants from seed (yay!) you will probably need to investigate cold stratification. Neither is difficult, just another step to follow. But for most vegetables and annual flowers, the basics will do.

Then a Miracle Happens

I always feel that way, anyhow! Tiny little plants sprout, unfurl their seed leaves, and then start creating tiny true leaves and getting taller by the day.

Watering

As your plant grows, gradually lengthen the time between waterings. For germination: soil continually moist. Little bitty seedlings: pretty much the same. Larger plants: let the soil surface dry out between waterings and make sure the roots are staying moist but not sopping wet.

A sprayer is great for the early stages, especially if the seeds are small and you don’t want to wash them all to one side. I find a small watering can with a narrow spout handy for later stages. Watering from the bottom (putting the water in the tray) is an excellent strategy, but tricky early on, because the tiny roots are going to be near the top of the pot. I usually start with top watering and then switch to bottom watering when the plants are a couple inches tall, more or less. Don’t let water sit in the tray and rot the roots; make sure it’s all sucked up or dump it out.

Labeling

I don’t care how you label your plants; just do it! You can stick labels (wooden, plastic, made out of whatever you have around) into pots or flats, or write on the outside of a container. But make sure you do. You will not remember what you planted where, and many seedlings look alike. Broccoli is exactly the same as cabbage well into the process; you can’t tell a hot pepper from a sweet one or a yellow tomato from a red one until they fruit, which is too late. If you’ve labeled a row in a cell tray, make sure that when you transplant into larger pots you label each individual plant. Otherwise, at some point they will get mixed up. (Yes, I have planted “unknown cucurbit” in my garden. Does it need a trellis to climb on? Who knows!?)

And then…

• Remember to keep the tops of the plants about two inches from the lights. Raise the lights or take away the pile of whatever you used to lift the trays higher.
• Keep an eye on your seedlings to spot any signs of trouble. Watch out for damping-off.
• If you’re using a potting soil with fertilizer included, you shouldn’t need to add any in these early stages. Make sure you’re watering regularly so the plants can take up the nutrients they need.
• You can find out how to transplant seedlings into larger containers on our “care of vegetable seedlings” page here.
• Plants can benefit from the simulation of breezes, either keeping a fan on low or periodically brushing the leaves with your hands. This, along with having the lights close to their tops, helps make the seedlings strong and stocky (instead of weak and leggy).

That’s it! Well, that’s not it, because we never stop finding new things to learn about, but it’s enough to begin with. Good luck to you in your seed-starting endeavors!

By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.