Why Start Early?
It's fun to experience the whole growing cycle as you watch baby seedlings grow into sturdy plants that bear delicious fruit and beautiful flowers. We often need to give plants a critical head start by germinating and growing seedlings indoors in early spring. Then when it warms up outdoors in late spring, we can plant sturdy, well-established seedlings to flower and bear fruit before cold weather sets in. Favorites like tomatoes, peppers and eggplant all need a long, warm growing period to set and ripen a good crop. Flowers like Dahlias, Echinacea, Rudbeckia, Salpiglossis, Penstemon, and perennial herbs like Lavender, Rosemary and Thyme will grow faster and flower earlier given a head start indoors. Except in the most tropical areas, all US summers are too short for them to complete their flowering and fruiting cycles if started directly in the ground.
When to Sow Seed Indoors
Generally, the time to start your seeds is about 6-8 weeks before the last expected frost date in your area, planting the seedlings outdoors about 2 weeks after that date. Another way is to plan to set out sturdy seedlings when night temperatures stay in the 50-55°F (10-13°C) range. Count back and sow seeds 6 to 8 weeks before that date normally arrives. If you don't feel confident about timing, consult an experienced gardening friend, ask at an independent garden center or seek the advice of your local Master Gardener program (usually available through the University Co-op Extension Service in your area.)
Getting Started
An easy-to-use seed starting kit can make growing your own plants fun and successful, and we have the perfect setup! The Sunkit Seed Starting System includes a high-quality heat mat that allows heat lovers like tomatoes, peppers, eggplants, and all heat loving flowers and herbs to germinate reliably and grow well. A 72-cell seedling tray and waterproof tray to go underneath will hold enough seedlings for bountiful crops. A 2-inch humidity dome with adjustable vents holds in moisture and warmth while seedlings are germinating. This kit has everything you need to start your own vigorous, well-grown seedlings. We also have the Sunpack Grow Light System and Seedling Heat Mat available individually that will work with any type of seedling container.
We really love the Sili-Seedlings Silicone Seed Starting Trays. They are made of heavy duty 100% BPA free, food-grade silicone. They are flexible, durable, sterilizable after every use and dishwasher safe! Rooted seedlings slip easily out of each pliable, tapered cell with their roots intact, so transplanting is less messy and there is minimal transplant shock. You may also choose to use your own recycled containers. Your planting containers should be at least 2-3 inches deep, with small holes for drainage. You can use plastic yogurt or cottage cheese containers, 3 or 4 inch wide plastic plant pots or 6 packs, or half-gallon milk cartons cut lengthwise, all with drainage holes punched in the bottoms. Just make sure your recycled containers are cleaned well before using!
A good quality seed starting mix is imperative! (Ordinary garden soil is not a good choice, as it often contains weed seeds and fungus organisms, and it compacts far too easily.) After rigorous trials, the mix we had the best success with is available online, Fort Vee Seed Starting Mix. This well-balanced, complete germinating mix is good for both indoor and outdoor use and will increase the mineral and antioxidant levels of your seedlings and provide good moisture retention at a crucial stage in their development.
Before you fill your containers and sow seeds, be sure to wet your seed starting mix, add water slowly and combine well, so moisture level is uniform. Your moistened mix should have the consistency of a wrung-out sponge. Fill each container with mix, leaving enough of a reservoir so that when watering, it won’t spill over the top. Tap it lightly on the tabletop to settle the mix. Use a plastic or wooden plant label with the variety name and sowing date and slide it into the container. Make a seed furrow or holes about 1/4 inch deep and carefully drop in individual seeds about an inch apart. Sift some more starting mix between your hands to fill the furrows and firm gently to be sure the seeds have good contact. Keep a watering can handy to water seedlings regularly. We recommend the Haws 2 Pint Heritage Watering Can, we’ve found that it’s the ideal size and spray pattern for gently watering delicate seedlings (and we tested several cans!).
Pricking Out and Potting Up
When seedlings are 2 to 3 inches tall and have several sets of true leaves, they can be transplanted into deeper containers or individual pots, so they have room to grow. Always use fresh, new potting soil. Lift the seedlings gently from your germinating container, a butter knife is very helpful for this. Try to get all the roots and disturb them as little as possible. Make a planting hole in the new container and nestle the seedling a little deeper than it was originally. For tomato plants spindly with long stems, you can bury them up to the topmost leaves, and new roots will grow along them. Gently press the mix around the transplanted seedlings and water gently to settle the soil. Now, plants can be fed with half strength fertilizer every 10 days to give them an extra boost. Use a good, high nitrogen liquid fertilizer like our favorite Neptune’s fish emulsion diluted to half normal recommended strength. Continue to give your rapidly growing seedlings as much light as possible and rotate them regularly so they grow evenly and do not lean in one direction.
Planting Seedlings in the Garden
When the weather outdoors has warmed into the 50-55°F (10-13°C) range at night, it's time to harden off or gradually acclimate your seedlings to outdoor conditions. Put them outside in a protected spot for a half day at first, then 2 or 3 full days. A spot with morning sun and afternoon shade is ideal. Then gradually move them into full sun, starting with mornings then all day long. Plan to transplant into the garden in the late afternoon or on a hazy or cloudy day to minimize stress. Proper garden bed preparation is important for healthy, vigorous plants. First weed the garden bed very well. Then add a few inches of compost and some dry organic fertilizer and thoroughly incorporate them into the soil with a shovel or digging fork, there are a few that we highly recommend. Down To Earth All-Purpose 4-6-2 organic fertilizer is our go-to choice of fertilizer for plants that flower or fruit. Also, Down To Earth Bio Fish 7-7-2 Organic Fertilizer for success with all Brassica family members including broccoli, cauliflower, Brussels sprouts, cabbage, kale, pak choi, and all types of greens. We also use Bio Fish fertilizer to boost heavy feeders like rapidly developing corn, tomatoes and cucumbers both early and midseason.
After carefully transplanting your seedlings, water well to settle the soil and help with transplant shock. Keep your young plants moist but not soggy, making sure they don’t dry out while they are establishing in their new spot. They can be mulched with organic materials like straw or wood chips after planting. This will provide the even moisture balance needed for healthy, disease-free growth and early big fruit sets, and will also discourage weeds.