Seeds are perfectly packaged plants just waiting for the right conditions to grow. Seeds need warmth, air and water to sprout, or germinate. Some are so simple to grow that you can just scatter them on top of soil and they'll germinate. Others need a bit more coaxing. Starting them on a bed of cotton balls will get them off to the best start. Cotton wool may be used instead of cotton balls.
Ready, Set, Germinate
Fill the bottom of a seed tray with a layer of cotton balls. Pull the cotton fibers apart a bit to make a soft, loose bed.
Mist the cotton with water until it is evenly moist but not soggy. Use a spray bottle for that task.
Place seeds on the cotton, spacing the seeds about 1 to 2 inches apart, depending on their type. Small seeds should be at least 1 inch apart. Seeds of carrot plants (Daucus carota) are examples of small seeds. Carrots grow as perennial plants in U.S. Department of Agriculture plant hardiness zones 4 through 10 but usually are grown as annual plants.
Cover the entire seed tray with a clear, plastic bag, and seal the bag's top. Ensure no part of the plastic bag touches the surface of the cotton balls. At least 1 inch of space should be between the top of the seed tray and the top of the plastic bag. That distance will ensure the seeds stay evenly moist and warm.
Set the seed tray in a location where the daytime temperatures stay between 68 and 75 degrees Fahrenheit. Indirect sunlight is best for many kinds of plants' seeds to germinate, but some plants' seeds need darkness in order to sprout. So expose your seed tray to dark as well as light. Read the seed packet to determine the light conditions your particular seeds need to germinate.
Check your seeds every other day to ensure they are not too moist, which will lead to rot, or too warm. Germination should occur within a few days, depending on the seeds. Some take up to 20 days to sprout, but most sprout within five to 10 days.
Remove the plastic bag after the seeds sprout. Keep the cotton moist, not soggy, and give the young plants, or seedlings, indirect sunlight.
Move your seedlings to a new, more permanent home when they have roots, stems and their first true leaves, which form above the first leaves, called the seed leaves. True leaves are a pair of leaves that look like the adult plant's leaves, whereas seed leaves are usually smaller and shaped differently.
Plant each seedling in its own 3-inch-diameter pot, plant several seedlings together in a larger pot or plant the seedlings directly in the ground outdoors. Plant each seedling with its cotton, covering the plant with soil only to the top of the cotton. If you use pots, ensure each pot has bottom drainage holes, and use potting soil as the growing medium in the pots.