Ready to get into the swing of spring but chilly, damp weather has you stuck indoors? Satisfy that urge to grow by setting up your own seedling nursery. It's fun, fulfilling, and saves you money. Here's how to get started.
Choose a potting mix specifically formulated for seed sowing, such as Miracle-Gro® Seed Starter Potting Mix. You don't want disease pathogens that could damage young plants. A good potting mix will hold moisture and drain well, and have a fine texture that allows young leaves to emerge easily.
Look for small trays or shallow containers 2-3 inches deep and something like plastic wrap or glass to cover them to retain humidity and warmth. Even the clam-shell containers from strawberries and cherry tomatoes from the grocery store work fine. The seedlings won't be in these containers long so they don't need to hold much soil mix.
Lettuce, beets, and spinach seeds germinate easily at room temperature. Warm-season plants, such as tomatoes and peppers, require a boost of heat to encourage sprouting. A sunny windowsill or the top of the refrigerator are commonly used to start seed. Small propagation mats that keep soil in the 68-70 degree range are available at major garden centers.
Fresh seed is vital for good germination. Look for the "packed for" date on the seed pack. You'll also see the seeds' germination requirements - soil temperature, whether the seeds need dark or light to germinate, and how many weeks before the last frost to plant.
Don't get too far ahead of Mother Nature. It's always better to set out stocky, healthy seedlings into the garden rather than ones that are weak and leggy from growing indoors too long. Start seeds of cool-season plants like lettuce, beets, kale, and spinach indoors 3-4 weeks before planting out. Grow heat-loving plants like peppers and tomatoes indoors 4-6 weeks before the last frost date in your area.
Moisten soil mix to the consistency of a wrung-out sponge
Fill container with mix and tamp it down lightly
Sow seeds on soil surface taking care to space them from 1/8 to ¼ inch apart depending on the size of the seed
Cover seeds with a thin layer of soil mix and press lightly
Soak seed tray in a shallow container of warm water until soil mix is thoroughly moistened but not saturated
Remove from water and allow to drain
Cover seed tray and place in warm area to germinate
Look at your seed container daily to check for signs of germination. As soon as the first leaves break through the soil, move them to a place with at least 6 hours of bright light and good ventilation. Then, remove the cover.
Too much water encourages fungal growth. Yet, too little water dries out delicate roots, making your seedling wither. Test to see if your container is ready for water by weighing it. Lift it. If it feels light, it's time to water. If it's heavy, wait another day or two. Use a spray bottle to water them or set them in a shallow tray of water to soak for a few minutes.
The first 2 leaves that emerge from the seed are called seed leaves or cotyledons. The third leaf to emerge is the plant's first true leaf. When the plants have 2 true leaves, it's time to transplant them from the seed tray into small pots of their own.