When it comes to growing your own food, there’s only one thing more satisfying than seeing your plants go from wily seedling to ripe, juicy fruit, and that’s seeing your plants go from a miniscule seed to ripe, juicy fruit. Details below.
Sure, starting plants from seed requires perseverance and dedication, but the payoff of watching those wee shoots sprout forth from the soil is huge. Insurmountable, even. (OK, maybe biting into the resulting fruit or veggie is a bigger deal—but not by much.) There are a few things to consider when starting seeds indoors, including which varieties of seeds to buy (check out the Seed Selecting 101 for tips), the needs of each seed variety, the amount of time and germinating conditions of each variety, and a commitment from you to see them through. And patience. You’ll need patience.
FINDING A LOCATION
When thinking about where to situate your indoor seed garden, keep in mind factors including pets, children, a source of natural light, and appropriate ambient temperature. You’ll need an area with a south-facing window, an average room temp between 65 and 70 degrees Fahrenheit, and a power source for artificial light.
Choose clean, appropriately sized containers with holes in the bottom for proper drainage—and remember that some seed varieties, like pumpkins, require more room than others, like onions. You can purchase readymade containers like the one in the photo at right, or you can make like HOMEGROWN member Andrea and repurpose yogurt cups and salad bar boxes into fully functioning seed flats. Fun!
PLANTING (AND TRANSPLANTING)
There’s dirt and then there’s dirt. Unfortunately, when it comes to starting seeds, you can’t scoop shovelfuls straight from the yard: The microorganisms in backyard soil can harm germinating seeds. Sticking with a premixed professional soil is safe—or check out Kristin’s directions for making your own potting mix using coir (or peat moss), vermiculite, and perlite.
When sowing your seeds, fight the feeling that more is better: Stick to just a few seeds per cell. You ultimately want one or two seedlings that are strong and healthy rather than a mess of weak sprouts vying to survive. Follow the individual seed packets’ instructions for number of seeds per cell and planting depth. As seedlings grow, you’ll eventually transfer them to larger containers—which makes labeling each cell vitally important. You have to know what’s what if you want to give your pups what they need!
En route to germination, most seeds need moderate light, rather than direct sunlight, for about eight to ten hours a day; refer to the seed packet for specific directions. Some seeds like a south-facing window; some require partial or full darkness; others need extra artificial light.
For most varieties, you’ll need to maintain a soil temperature of 80 to 85 degrees—a challenge in some parts of the country during winter or very early spring. Placing your containers on heating mats, under heat lamps, atop a refrigerator or another appliance, or covering your seed trays can help keep the soil warm.
Once your seeds have germinated and you’ve got sprouts poking above the soil, you’ll need to supplement ambient light with artificial help: Emerging seedlings require about 14 to 16 hours of light per day. Low-hanging fluorescent lights, often called grow lights, usually work. For ideas, check out Melissa’s DIY shop-light setup and Jaccqueline’s floor lamp outfitted with full-spectrum fluorescent bulbs.
Germinating seeds don’t require a lot of water. A daily mist should keep seed trays from drying out, and covering the seeds with a propagation dome—a.k.a. a clear plastic lid, like the one in the photo at right—will help hold in moisture. Just remember to remove the dome once your sprouts have emerged.
When your seedlings are strong and nearly ready for transplanting into the garden, it’s time to harden them off—basically, a process by which you introduce them to the outdoors gradually, for a few hours at a time. Incremental exposure to the elements—sun, wind, rain, your neighbor’s curious cat—will allow them to adjust to their environment and, ultimately, to thrive and survive climactic conditions. Start by moving your seedlings outside for three hours a day, then five, then eight to ten, and then overnight.
MORE SEED-STARTING RESOURCES
• HOMEGROWN member Janine shares info on—and great photos of—her home-built seed-starting shelf with adjustable grow lights, a setup that lets her raise the lights to accommodate the seedlings as they increase in height. Smart, right?
• Mother Earth News offers a thorough primer, including info on when to sow seeds indoors, outdoors, and when to transplant.
• This chart from Johnny’s gives specifics on when to start specific types of seeds outdoors and when to move them outside.
• Plug your zip code into this tool from the Old Farmer's Almanac to find the best planting dates by phase of the moon. (If the site doesn't automatically register your zip, scroll midway down the page to “Location”).
• You Grow Girl shares a downloadable spreadsheet that will help you calculate seed-starting dates from year to year.
• The Weekend Gardener features a week-by-week growing guide.
• Here on HOMEGROWN, High Mowing Organic Seeds shares valuable tips on storing seeds to plant next year and a quick germination test to determine whether your saved seeds will thrive next season. For more from HMOS, check out their website.
• Download HOMEGROWN how-to cards on creating a self-watering container and on saving tomato seeds.
A few more seeds to plant in your brain: Get tips on selecting seeds, find out how to save them, learn how to make your own envelopes for storing them, and start planning your garden for next year. Got a question? A tip to share? Post it below and keep the conversation alive and growing! Then troll for more things to plant, grow, cook, preserve, make, and craft in the HOMEGROWN 101 library.
PHOTOS, FROM TOP: (CLOSE-UP) PETE AND IZZY'S MOM; (TOP VIEW OF SEED TRAY) MICHAEL; (TRAYS ON TABLE) PETE AND IZZY'S MOM; (SEEDLINGS UNDER GROW LIGHT) JULIE; (COVERED SEEDS UNDER GROW LIGHT) CARRIE SEAL-STAHL
Here's a tip for those of us who want to put our starts out a little early:
Cut off the bottom from a "sport top" drink bottle and place it over tender seedlings. The bottle protects the seedlings from wind and critters, and the top serves as a release for excess heat. A mini greenhouse born from the recycling bin! Thanks to Julie for sharing this! Her full blog post about using sport top bottles can be found here.
Fluorescent lighting (particularly the new T-5 bulbs which triple the light output of normal fluorescent bulb without increasing the wattage) fulfills only part of the equation. In cold environments, like a chilly basement in a home situated above the frost line, it would be a good idea to place a heating pad underneath your seedling tray. Many gardening supply houses sell heating mats just for this purpose. Many plants, particularly warm weather veggies, accelerate their growth when the soil around their roots is warm.
Chris: Thanks for the ace tip. And presumably one can put the heating pad on a timer, too, so one (ahem, me) wouldn't go off and forget about it? Or am I living in the 1970s and thinking of a totally different type of heating pad?
Jennifer: You're welcome! Yes, I do mean a regular ol' fashioned heating pad, just like what drugstores have been selling for sore muscles since the 1970's. Despite the warning on the box (put there mainly so the company can avoid frivilous lawsuits) leaving it 24/7 isn't a problem for a lot of people. If it bothers you, then you can use a cheap hardwaare store timer.
A quick search using keywords "gardening heating pad germinating seeds" came up with a page from Chow Hound in which one person says he has "...used bottom heat for seed germination and early growing for some years for plants that like warm soil for germination" and that "if you use bottom heat for germination, cover your starting trays with clear plastic to hold in moisture and heat until the seeds come up." Another person there posted a handy chart that shows percentage and time for germination at various temperatures.
Good stuff. :)
Chris: Good stuff, indeed. Thanks for finding it and passing it along.