Do you remember your first time?
The teacher handed out Dixie cups and dirt, and we planted our one shiny bean. We put the cups on the sunny windowsill by the guinea pig cage and waited until the day when our beans suddenly sprouted.
I don’t remember if Mrs. Pearce taught us about seed coats and cotyledons. It doesn’t matter. She had me at Jack and the Beanstalk.
Since that first bean, I’ve grown thousands of plants from seed. I do it because it gives me a jump on Minnesota’s short growing season, helps me save money on plants and allows for a wider selection of varieties. But it’s a little more complicated than sticking a bean in a Dixie cup.
Here are some tips to ensure your seed-starting success.
When it comes to vegetables, start with the ones you like to eat. Then ask yourself a few more questions.
When I consider a veggie or an herb, I ask myself, “Who grows it better, the grocery store or me?” With flowers, I ask which varieties might be hard to find in the garden centers and which are likely to command too high a price when purchased as plants.
It takes a seed
To get the best results, buy seeds packaged for the current year. You can use seeds leftover from last year, but germination rates tend to decrease with time. Since packets usually contain more seeds than you need, try sharing with your gardening buddies.
After the long slog through a winter like this one, it’s tempting to get an early start. Don’t. Follow packet directions for when to sow. The general rule of thumb is that cool-season veggies and flowers (broccoli, cabbage, snapdragons, petunias) can be started indoors in early to mid-March, while warm-season plants (tomatoes, peppers, basil, nasturtiums) can be started in early to mid-April.
If you’re growing just a few plants, recycled yogurt cups or clamshell deli containers will work fine. (Be sure to soak any used containers in a diluted bleach solution to kill any residual pathogens, then rinse thoroughly.)
Seed starting kits with cell flats and trays are best if you plan to plant plenty. Most kits include clear humidity domes, which help create the moist, warm environment needed for good germination. And planting a single seed in each cell can make transplanting easier.
The right stuff
Resist the urge to use whatever potting soil you’ve got hanging around. Go out and buy soilless seed-starting mix. These sterile, lightweight mixes encourage root growth while discouraging dreaded “damping off,” a fungal disease that kills tiny seedlings.
Recently, I’ve been using seed-starting kits that include compressed pellets of coconut coir that expand when water is added. For me, it’s made seed starting faster, easier and more eco-friendly than kits using flats of peat, which is less sustainable.
When sowing seeds, follow the directions on the seed packet. Proper planting depth is important. Some seeds, such as lettuces and petunias, need light to germinate. So just press them onto the surface of the soilless mix, then sprinkle a little more mix on top.
When planting in flats, group seeds according to size so that tall seedlings like tomatoes won’t shade smaller ones like alyssum. If seedlings are about the same size, group them according to how quickly they germinate.
Remember to mark your seeds. I use Popsicle sticks from the craft store or leftover plastic knives and write the names with an indelible marker. Otherwise, I’ll forget what I planted.
Go for the light
Despite what I learned in elementary school, a sunny windowsill isn’t the best place to start seeds, especially in Minnesota. Frigid temperatures at night and hot sun shining through the glass during the day can be hard on seedlings, which need moderate, consistent conditions to flourish. And, with only weak spring sunlight, seedlings may grow leggy and weak.
You don’t need to buy an expensive grow-light setup. A combination of natural and cool fluorescent bulbs from the hardware store will do. Hang light fixtures from chains so you can move the lights away from the seedlings as they grow. (Optimally the lights should be only several inches from the top leaves for stocky growth.) Lights should be on for 12 to 16 hours a day. (A timer helps.) Some people use heating mats to speed germination, but I’ve never tried one.
Feed and water
Once you’ve planted your seeds, keep the soil moist — but not wet — for the first couple of weeks. After most of the seeds have germinated, remove the humidity domes. I like to run a fan in the room to improve air circulation and strengthen the stems of developing seedlings.
Wait to fertilize until the first true leaves appear, then use liquid fertilizer diluted to a quarter strength, once a week.
The hardening part
Two weeks before it’s time to plant the seedlings outdoors, you need to toughen them up. The “hardening off” process gradually accustoms vulnerable seedlings to outside conditions. When the weather is mild, bring out your flats and containers and place them in sheltered shade out of the wind for an hour or two. Take them outside every day, gradually increasing the amount of time they spend outdoors and the amount of sun they receive.
After a couple of weeks, choose a cloudy day or mild late afternoon to transplant your seedlings into your garden. Use a small spoon to scoop them out of their cells while holding them by their leaves so as not to break the delicate stems.
Water them in well — and prepare to be amazed.
Rhonda Hayes is a Minneapolis-based garden writer. She blogs at