Everything You Need to Know About Seed Starting
If you've never started growing anything from seed, it's easy to write the whole idea off as mysterious, difficult, or labor-intensive, but that couldn't be further from the truth. Seeds, dormant until they're placed in soil and given water, hold incredible potential for life once given the right conditions and a little love.
There are countless reasons to grow from seed. First, it's important to know that starting veggies, herbs, or flowers from seed is more cost-effective when compared to buying young seedlings. If saving money isn't enough incentive for you, know that starting from seed also gives you the opportunity to choose from far more variety than what's in stock at the local nursery. Ogling seed catalogues and drooling over rare varieties might just become your new favorite pastime. And usually, so long as you can commit to keeping the seedbed (the area where you've planted your seeds) moist until the seeds germinate, there's quite a high likelihood you'll find success. You'll have complete control over the quality of raising your plant baby, especially pertinent if you're committed to organic practices. If you live in a region with oppressive winters, seed starting indoors can help you get a serious jumpstart on the gardening season, giving your green thumb an outlet during darker days.
And we'll let you in on a little secret—seed packets usually contain every bit of information you need to grow that crop, from planting date and depth, to maintenance and care for the plant. Be sure to keep your seed packets handy as you embark on your new seed starting adventure.
Seed Starting 101
Thinking about starting vegetable or flower seeds in your own home? Our step-by-step video walks you through the entire process.
Purchase high-quality seeds packed for the current year—the year is always marked somewhere on the packet. If you've got old ones, you can test their viability by pre-sprouting them in a wet paper towel kept inside a plastic baggie and stored somewhere warm. Most seeds sprout between 2 and 14 days. If you have extra seeds from what you buy this year, store them in a cool, dark, airtight place, like a resealable plastic bag placed in the freezer.
Any container is fair game for starting seeds so long as it has drainage. It's perfectly fine to choose based on what you've got on hand or your preferred design aesthetic. Thoroughly clean terra-cotta or plastic pots before reusing them for seed starting. Large clay or plastic pots with drainage holes, also known as community pots work great a group of seedlings. Peat pots, cell packs, and pellets are naturally sterile, and because they can be directly planted outdoors, they are ideal for plants with delicate roots that might not like to be transplanted.
While potting soil usually works just fine, you can go above and beyond to ensure success by using a sterile soilless mix that's about one part milled peat moss to one part vermiculite with some perlite. You can either mix your own—all ingredients are readily available at nurseries—or you can buy a pre-made one. Most commercial seed-starting mixes also have enough fertilizer for about two weeks. Never use a mix containing topsoil or compost as these can impede drainage and rot your seeds.
Planting Trays and Covers
Overhead watering with a can is totally permissible, but you might find more even moisture by practicing something called, "bottom watering"—using plant trays under pots and filling them with water. Retain moisture and heat with by topping seeds with a clear cover. Clear plastic wrap can also be used to cover germinating seeds.
There's nothing worse than not remembering what's what after you've gone to the trouble of starting your own seeds. For that reason, always label seeds with the variety and date sown.
Seeds need light and warmth. Usually a sunny windowsill in a warm room will do the trick. Grow lights are not a requirement for starting seeds unless you live in an extremely light-deprived setting. If so, choose full-spectrum fluorescent lights that can be positioned directly above seeds and raised as seedlings grow. Grow lights not only provide the light required for healthy development, but they also warm the soil, speeding germination.
Before starting seeds indoors, find out the last frost date in your area by checking online. Read the seed packets to learn how many weeks before this date they should be started and when the seeds should be planted outdoors. Calculate your sowing date accordingly. Did you know that poppy seeds can be scattered directly on the winter ground—even on patches of snow? The seeds need weeks of cold to germinate, and plants will begin to emerge in spring. Again, a seed packet is a handy place to look for information.
Step 1: Hydrate Your Mix
In a large bucket or tub, gradually add tepid water to sterile soilless mix until it is evenly moist but not wet. "Like a rung-out sponge" is the texture you're after.
Step 2: Prep the Soil Bed
Cover the drainage holes of clay or plastic pots with a small piece of newspaper, and fill containers to the top with moistened mix. Tamp down mix so surface is firm and level, about 1/2 inch from the top.
Step 3: Make the Holes
Using your finger or pencil, make holes in mix. A handy rule is to bury seeds about twice as deep as they are thick. When in doubt, depth and distance will be listed on the seed packet.
Step 4: Remember to Label
Label pots with the type of seed and the date sown. Bottom-water containers by setting them in trays filled with an inch of tepid water.
Step 5: Finish Up
Cover containers with a clear plastic cover or clear plastic wrap. Place them in a warm, sunny spot. If you're using grow lights, place them two to three inches below the light source. For seeds that require darkness to germinate (noted on seed packet), use an opaque cover, and set them in a warm spot, such as the top of a refrigerator.
Check Containers Daily
Once you've sown seeds indoors, check containers daily for new shoots. Keep the seed-starting mix moist—but not soggy—until germination is complete and the emergence of new seedlings slows markedly or stops. At this point, remove covers. If you're using grow lights, leave them on 14 to 16 hours a day. Continue to bottom-water.
Fertilize and Pot Up Your Seedlings
As soon as seedlings produce their first true leaves, begin watering with a balanced fertilizer or fish emulsion diluted to one-quarter strength. Prick out seedlings planted in community pots, and transplant them to individual pots or cell packs filled with moist soilless mix. Lift seedlings by their leaves rather than by their delicate stems.
Raise Grow Lights
When soilless mix dries, water transplanted seedlings using a water breaker or mister that produces a gentle spray. As seedlings grow, raise grow lights, keeping them two to four inches above the plants.
Transplant If Necessary
If necessary, transplant seedling to a larger pot as it grows. Before planting outdoors, gradually harden off seedlings to prevent transplant shock: Two weeks before transplanting, place seedlings outdoors for a few hours at a time, gradually increasing their time outside until they are acclimated.
Martha's Seed Starting Tips
Martha and her head gardener Ryan McCallister get ready for spring in the Bedford Farm greenhouse—and show you all you need to know about indoor seed starting.