The Quintessential Seed-Starting Guide
Many in warmer climates around the country are gearing up to start seeds for their gardens. While we're weeks away from seed starting ourselves, it is the perfect time to dream, scheme and plan our gardens anew.
Why not consider creating your own Asparagus and Strawberry beds for a life time of chef-worthy harvests? Or make this the first year for a backyard treasure chest of freshly harvested Melons? Imagine your family's delight over homegrown Cantaloupe, Honeydew, Watermelon and specialties, like our Petit Gris de Rennes Melon, the hard-to-find champagne of Melons. Think ahead to Thanksgiving, and a table laden with your own roasted Brussels Sprouts and Butternut Squash, sautéed buttery Corn, and Pureed Turnip Clouds. Thanksgiving feels and tastes better when you've grown the vegetables yourself. Promise.
You could resolve to make Christmas an old-fashioned, personal one this year. You and your children could make homegrown and homemade gifts, like a three-jar Basil, Spinach and Arugula Pesto extravaganza; a Gourd birdhouse; herb-infused vinegars and olive oils, or sweet Lavender sachets from days of old.
What to Start When?
Certain varieties should be started indoors in advance because their days to mature harvest exceed the amount of time between your spring Frost-Free Date and your first fall frost. By starting them indoors, you gain a four to 14 week jump-start on plant development. Our Essential Seed-Starting Timetable provides a two-part overview of which vegetable, herb and flower seeds should be started indoors (by how many weeks in advance) or direct-sown into the garden after your spring Frost-Free Date.
Read the Seed Packets
Just about everything you need to know is detailed on each seed packet, including when to start seed indoors, proper planting depth, spacing, days to germination, ideal germination temperature and any special needs. Some seeds need a 12-week head start indoors while others shouldn't be started until three weeks before transplant outside. Pay attention to specific instructions about covering or not covering the seeds with soil: for the best germination, some seeds need light, while others crave darkness. Sort your start-indoor seed packets by the number of weeks they require in advance of your spring Frost-Free Date. Start a Seed Calendar. Prior to use, store seed packets in an airtight container, in a dry spot away from direct sunlight at a consistent 65 degrees F to 75 degrees F.
Use a Good Quality Soil-Less Seed Starting Mix
Seeds that are started indoors should be planted in new, sterile, finely textured, soil-less seed-starting mix that contains sphagnum peat, brown coir (ripe coconut husk fiber), fertilizer, perlite and/or vermiculite. Good seed-starting mix helps promote thorough root development and avoid 'damping off': when young seedlings perish from fungal diseases brought on by contaminated old seed-starting mix, cool, moist conditions and/or poor air circulation. Premoisten the seed-starting mix with room temperature water in a sterile plastic container. If you don't do this, the dry soil-less mix will run out of your planted containers and ruin the seed planting depth. Select seed-starting flats, pots or other containers that have good drainage and sterilize them before use. Plastic is better than terra cotta for moisture retention. After planting, water carefully and well with a hand spray bottle and lightly tamp the soil surface to make sure that the seeds are in direct contact with the soil. Label each variety to avoid any confusion later.
Moist for Germination, Then Stay on the Dry Side
When you start your seeds, it's important to keep the soil-less mix consistently moist, particularly in the winter when humidity levels are so very low. We cover our seed-starting flats with a clear dome top or a piece of plastic wrap to prevent moisture evaporation. Check them every day and remove the cover or plastic wrap as soon as the first sprouts emerge. From then on, let the soil surface dry out briefly between waterings to inhibit disease and encourage strong root growth. How often should you water? That depends on the type of container, the growing mix, the air temperature and the size of the plants. When you water, you may use a hand spray bottle to gently water the soil-less mix without dislodging the seeds. Make sure that all of the soil is gently moistened~not just the top layer. You can also water from the bottom up. Pour a 1/2 inch layer of water in a large tray and place your seed-starting flats or containers in the tray. The soil-less mix will wick the water up from below.
Provide Consistent Temperatures
Most seeds germinate best when the soil temperature is 65 degrees F to 75 degrees F. In a cool home or greenhouse, you can put your seed-starting flats on top of seed heat mats (available at your local garden center or online source). Once the baby seedlings are up and growing, they prefer cooler 60 degrees F to 65 degrees F temperatures and good air circulation. Running a small fan on the lowest setting near your seedlings will help keep them cool and discourage disease (not necessary if your home is cool and dry).
Provide 16 Hours of Bright Light Every Day
Starting seeds on a sunny windowsill doesn't work~there is simply not enough strong light~seedlings will be weak, tall and spindly. You need grow lights. They don't have to be expensive or tricky. You can find them at your local garden center or hardware store. Hang the grow lights on chains so you can move them up as your seedlings grow. The grow lights should be just an inch or two above the seedlings at all times for maximum rooting, growth and warmth. If necessary, rotate flat placement for even light exposure. Put the grow lights on a timer so you don't forget to turn the lights on for 16 hours and off for eight. Real warmth-lovers, like Eggplants, Peppers and Tomatoes, like to be coddled with 24-7 grow lights until they become 'toddlers' able to handle the cooler, eight hour dark period. (Maybe you and another gardening friend or two can combine your seed-starting efforts under one set of grow lights.)
Baby Seedlings Need Food and Elbow Room
The embryo inside every seed contains all the nutrition needed for germination. But once the seeds sprout and the young seedlings have put out their first true leaves, they need a consistent supply of nutrients to sustain healthy, vigorous growth. Water your seedlings weekly with a half-strength solution of liquid all-purpose fertilizer, alternating with a dose of seaweed or fish emulsion. Once your seeds have germinated, thin the flats out to the strongest individual seedlings to avoid overcrowding and tangled roots. If you are patient and careful, you may be able to transplant some of the thinned seedlings to other cell packs or pots. The younger they are when you do this, the better they will grow.
Toddler Seedlings Need 'Hardening Off'
Graduating from life indoors as 'toddler' seedlings, to life outside as 'adolescent' plants can be traumatic if it happens too abruptly. So, easy does it. Seven to ten days before you plan to transplant your seedlings, start bringing them outside for daily outings so they can become used to the big outdoors: this is the process of 'hardening off'. Put them on a cart or wagon and wheel them into a spot that's protected from wind and intense afternoon sunlight. Bring them back indoors in mid to late afternoon. Gradually, as you extend their daily sojourns, your seedlings will become more acclimatized to sunlight and temperature fluctuations. To reduce unnecessary stress, plant the seedlings in their new garden home on a more calm, overcast day and don't rush it. Even if it is unseasonably warm, do not plant hardened off seedlings before your customary spring Frost-Free Date. Chilly night temperatures can stunt even the strongest of seedlings and result in failure to thrive. Patience really pays off in the garden.