Planting From Seed 101By George Wiegel, Pennsylvania Certified Horticulturist (PCH)
How to successfuly start growing plants from seeds
Why grow plants from seed? "So you can see the roots grow like spider webs,” said 7-year-old Jimmy. "So you can watch one baby leaf turn into a whole baby plant”, said Jimmy’s classmate Lauren. "So you can plant a seed, then grow the plant, then eat the tomato, then spit out the seeds to grow more plants and eat more tomatoes and spit out more seeds…” said Daniel, a Master Gardener in the making.
The wonder of seed starting and the promise of warmer weather make seed catalogs and displays a joy. Keep these tips in mind while gleefully gazing at the colors and bounty of summer.
Let the garden centers grow the basic beefsteak and cherry tomatoes. Start seeds of unique varieties, such as heirlooms or internationals.
Check the backs of seed packets for the ideal planting time and place. Beans and peas, for instance, resent having their roots disturbed, so plant these seeds directly in the ground after the last frost. Heat loving plants such as tomatoes and peppers need a head start. Start these indoors six to eight weeks before the last frost.
Three keys to successful seed starting are light, soil-less planting mix, and water. A south-facing window is perfect for light. There is no need to purchase elaborate grow lights; fluorescents will work as long as they give the seedlings 8 hours of light and do not burn them. Purchase bags of seed starting mix at local garden centers or a favorite supermarket. Pour it into a big bowl and moisten it before putting it into containers. Or use Jiffy Pellets, with a biodegradable netting over a soil-less mix. Put them in water and they puff up into mini pots complete with a hole for your seeds.
Here are some seed starting tips:
Moisten the seed starting mix and scoop it into seed-starting flats or containers. Don't press too hard — seeds will have a harder time germinating in compacted soil.
Determine the planting depth of the seed from the instructions on the seed-starting packet.
Make a hole in the seed starting mix with a small tool such as a screwdriver or a chopstick and plant larger seeds with your fingers. Smaller seeds (such as petunias) are hard to sow in small numbers, so plant a few in each pot and thin the seedlings as they germinate and start crowding each other.
Cover the flat with a clear plastic cover or plastic wrap until the seeds germinate. This will help conserve moisture and prevent evaporation. It is vital that you keep the seeds moist, but not wet, or they will not germinate properly.
Water, or lack of water, causes the most cases of Sudden Seed and Seedling Death Syndrome. Windowsill seed starting trays — with humidity domes — can help lessen seedling death by allowing the gardener to control the humidity in the tray and keep out drafts from windows. Water from the bottom of the tray, which encourages the roots to grow down, or use a nozzle-and-bulb or other gentle source, to avoid washing out the seeds.
If the seeds don't sprout, it could be because the soil was too wet, too dry or too cool. Use a heat mat, or place the seed trays on top of the refrigerator to keep germinating seedlings warm. Once the seeds have sprouted, remove the plastic wrap or domes, and remove the heat mat or take them off the refrigerator. Keep the seedlings slightly moist, but not wet at all times.
Tall, floppy seedlings are an indication that your plants aren't getting enough light. Move them to a brighter location if they start to get long and leggy. If you are using grow lights, lower them so the bulbs are just a few inches above the tops of your plants.
Young seedlings that rot at the base and die are the victims of a soil-borne virus. This is called damping off. Use a sterile germinating mix and keep the seedlings from getting too wet. Water them from the bottom, letting water soak up into the soil instead of down. It also helps to water in the morning so the seedlings have time to dry off before nightfall.
Seedlings need to be "hardened off” before planting them out into the garden. It sounds harsh, but this extra step will save many plants from a quick death in your garden. When all danger of frost is past, set the plants outdoors in a sheltered location for a few hours a day. Increase the time spent outdoors each day, and gradually move them from full shade to partial sunlight. Be sure to water them daily, as the warmth and wind will dry them out more quickly than indoors. During the final three or four nights before being transplanted, they should be spending all day and night outdoors.
Transplant the seedlings on an overcast day, or late in the afternoon, so that they aren't immediately faced with hours and hours of direct sun. Water them faithfully, mulch and enjoy.