There are a few reasons a gardener may choose to start plants from seeds. It is less expensive if you plan to grow a large number of plants, there is often more variety when shopping for seeds than seedlings, and it enables you to get a headstart on the growing season.
Starting your own plants from seeds is not difficult but it does require special care. Seedlings are delicate and it is important to notice and address problems quickly if you want them to pull through. With a little experience, you will soon be confident starting your own plants.
It is easy to underestimate the amount of light your seedlings need to thrive. They may germinate and even grow in low light situations, but without sufficient sun, they will be weak and leggy.
Most homes will not have sufficient natural light to start seeds. Instead, use a grow light or other fluorescent bulb to provide your seedlings with the light they need. If you opt for a fluorescent bulb not specifically designed for plants, place the seeds under one cool and one warm bulb for the best results.
Provide at least 12 hours of light each day and up to 16 for healthy seedlings.
Take your time when planting your seeds. Each plant will have different directions for how deep the seed should be planted. Plant too deep and the seed may not emerge from the soil. Plant too shallow, and the plant won't develop a sturdy root system. The exception to this is plants that require light to germinate. If your seed packet mentions this, sprinkle the seeds lightly across the surface of the soil and press gently.
Sufficient light and proper moisture are the two most important ingredients to healthy seedlings. Too much water and your seedlings will rot or develop fungus. Not enough moisture and they will shrivel and die.
Keep the soil damp, not wet. You can water from the bottom to make it easier to maintain proper moisture levels. Place seedling containers into a larger tray of water. Leave them to soak up water through the drainage holes in the bottom of their containers. After 30 minutes, remove the seedling containers from the tray. Check the soil daily and repeat as needed to keep the soil damp.
Once your seedlings are ready to transplant outside, you don't want to keep them waiting too long. Left inside, they will start to get leggy and not be as hearty when transplanted. Determine when you will be transferring the seedlings outside; start your seeds at least 4 weeks, but no more than 6 weeks, prior to that date.
Seedlings grow best when kept at room temperature, between 65 and 75 degrees F. If the area where you plan to keep your seedlings doesn't stay this warm, purchase a warming mat designed to keep the seedlings at the correct temperature.
The top of the refrigerator is a popular spot to start seedlings, as it is generally warm, draft-free, and out of the way.
Seedlings are fragile, and recognizing signs of stress early allows you to adjust their environment quickly. Seeds that don't germinate at all may be old. Seedlings that sprout and seem to be doing well, then die suddenly may have dampening-off disease. This fungus is typically the result of too much moisture in the soil.
If your seedlings grow tall and spindly, with tiny leaves, they probably need more light. Yellow streaks on the leaves are a sign of insufficient nutrition, as are leaves that turn purple. Once your seedlings develop their first set of leaves, you can add fertilizer to the watering solution, following the instructions on the packaging carefully.
Seeds are inexpensive, so it is easy to plant more than you need. As long as you are aggressive about thinning the plants once they develop two sets of leaves, it makes sense to start more seeds than you plan to transplant. Not all of the seeds will germinate, and you should plan on some seedlings dying off or looking unhealthy, even with the best of care. Planting more than you need allows you to select only the healthiest for transplant.
Once the seedlings develop two sets of leaves, it is time to thin the plants, removing the ones that have not grown as well or look sickly. Thinning allows the strongest seedlings to develop and prevents overcrowding, which can lead to disease.
Clip seedlings that you want to thin at the soil level. Don't thin by pulling, as you can easily disturb the delicate roots of the other plants.
Seed-starting mix is sterile and helps protect your seedlings from disease.
Fresh seeds have a higher germination rate than older ones, so buying from a trusted gardening source is important.
Use pots specifically designed for seed starting. They allow you to start many seeds at once and will have ample drainage holes, making it easier to maintain proper moisture levels.
Hardening off is the process of moving your seedlings outside. Doing this gradually is important, as the shock of moving directly outdoors can stress and even kill the seedlings. Start by placing your seedlings outside for an hour, gradually increasing the amount of time they are outside each day. After a week to 10 days, you can transplant them into your garden.