How to start seeds at home if you’ve never tried it before
"Growing Together" columnist Don Kinzler says it's easy to do if you follow the right steps.
FARGO — Starting your own plants from seed isn’t just about getting plants on the cheap. Watching seeds sprout indoors kick-starts spring long before planting season arrives outdoors.
Growing your own vegetable or flower transplants isn’t difficult, and if I can do it, anyone can. Even if you’ve never tried or had mixed results, with a little hands-on experience, you’ll be successful in no time.
The overall plan is to sow the seeds, coax them to germinate, grow them in the seed tray until they’re large enough to handle and then transplant each seedling into individual pots, cups or cell packs. Seeds can be purchased at garden centers or from mail-order seed companies. Seed-starting equipment can be repurposed from many materials.
Some vegetable and flower types are easier to grow than others because they sprout quickly and don’t need as much indoor growing time, including marigold, zinnia, alyssum, cleome, cosmos, four o’clock and nasturtium. Types that are slightly more difficult and require more weeks to develop, but can be accomplished easily with experience, include petunia, moss rose, salvia and snapdragon.
Easy-to-start vegetable transplants include tomato, pepper, cabbage, cauliflower, broccoli, melons, cucumber and squash.
It’s best not to start too early, because plants easily become overgrown indoors. Suggested seeding dates are:
- March 1: Impatiens, petunia, snapdragon and lobelia.
- March 15: Alyssum, dianthus, salvia, broccoli, cabbage, pepper and eggplant.
- April 1: Tomato, cleome, marigold and lettuce.
- April 15: Cosmos, calendula, nasturtium, four o’clock and zinnia.
- May 1: Squash, melons and cucumber.
Use a mix that’s labeled for starting seeds. The tray in which seeds are started can be one designed for that purpose purchased from a garden center, or you can repurpose a container that’s at least 2 inches deep.
Punch or drill holes in the bottom for drainage. Clear plastic containers from the grocery store bakery or deli work well, and with a lid included create a miniature seed-starting greenhouse.
Steps to follow
- Moisten the seeding mix the day before using by adding water to the bag and mixing well. If the mix isn’t pre-moistened, it’s difficult to wet after seeding and seeds might float to the surface.
- Fill the container to the top with mix. It will settle slightly after seeding and watering.
- Use a separate container for each different seed type, because they germinate at different rates.
- Broadcast seeds over the surface or plant in rows.
- Small seeds the size of a poppy seed should be sprinkled on the surface without covering with mix. Cover larger seeds to a depth about twice the seed’s diameter.
- Label with the seed name, type and date.
- Water gently with a fine mist or sprinkling can. Use warm water to stimulate faster germination.
- Cover the container with clear plastic wrap or a clear lid. If watered well after the seeds are sown, additional sprinkling might not be needed until seedlings appear, unless the surface appears dry. Consistent moisture is important.
- Place seed trays in a warm location between 70 and 78 degrees. Electric seeding mats, available at garden centers, are a great investment.
- Seedlings need light immediately upon germinating, or they’ll stretch and become spindly. I prefer to locate the seed trays under lights, either fluorescent or LED, immediately after seeding, with a timer set for 16 hours of light. If lights aren’t available, place the seed tray in a window that receives direct sunshine as soon as seeds sprout.
- Most seed types take seven to 10 days to germinate. When most of the seeds have sprouted, remove the container’s clear cover and remove from the heat mat, if used.
- The best temperature range for growing the newly emerged seedlings is 65 to 70 degrees. Let the surface of the mix dry between gentle waterings.
- When seedlings are just large enough to handle easily, transplant from the seed tray into individual cell packs or small pots or cups for continued growth in a quality potting mix.
- If germination is poor or slow, the temperature is most likely too low. If seedlings become stretched and spindly, light levels are too low, or the seed tray wasn’t placed in sufficient light soon enough upon germination.
With a little experience, starting our own seeds yields transplants that rival those sold at garden centers.
Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at email@example.com.