It’s easy to buy seedlings, and there are many good reasons why you may wish to start your own plants. By starting your own seeds, you have a much greater selection of flowers, vegetables and herbs to choose from. For example, old favorites like hollyhocks and less common varieties of herbs and perennials as well as heirloom vegetables might not be available as plants, or stocks may be limited. Plants with fine seeds should also be started indoors because they can easily wash away in the rain and they may have a difficult time competing with weeds. Starting your own seeds can also help you extend the growing season so you can enjoy a longer, more productive harvest. So why not get started today?
Containers for Starting Seeds
Traditionally, seeds are started in flats or peat pots. There are various sizes of plastic trays, peat pots and the popular Jiffy-7, a flat, peat-moss wafer, available. When moistened, the Jiffy-7 expands to form a small, self-contained pot of soil into which a seed is sown directly. This is an excellent choice when sowing seed of plants that do not like their roots disturbed during transplanting. You might also use folded newspaper to start your seeds. If you reuse containers, wash them with absolution of 9 parts water to 1 part bleach to prevent transfer of diseases to your seedlings.
It is best to use a light, soilless, seed-starting mix when starting seeds. These mixes are sterile, meaning young seeds do not have any weed seeds to compete with, and there are no harmful bacteria, insects or other pests in the soil right away. Good seed mixes also contain adequate nutrients to carry seedlings through until transplanting. Do not use garden soil, as seeds will not germinate well in the heavy soil, and a fungus disease called damping off is common.
Temperatures for Seeds
Most seeds, like tomatoes or peppers, require warm soil in order to germinate. You can heat the soil of the seedling flats with a heat mat. Seed trays can also be placed on top the refrigerator or hot water heater. Do not put seed-starting trays on a windowsill; nighttime temperatures are too cool to allow for good germination. Seeds need consistent warm temperatures of 75 degrees or warmer for optimum germination. Once seeds have germinated, remove the heat source to prevent plants from growing too quickly and becoming “leggy.”
Seeds need to be kept constantly moist (not soggy) in order to germinate.
Be sure to label your containers with plastic or wood plant stakes and write the plant name and the date sowed. Set trays in a warm spot and check daily to keep evenly moist.
Seeds should be sown 2-10 weeks before the last spring frost date. Your seed packet will provide this information as sowing dates can vary for different plant varieties or even cultivars of the same plants. Fill your containers almost to the top with moist growing mix. Tamp it down gently and smooth it out. Gently press the seeds into the mix, covering the seed at a depth of more than 2 times the size of the seed. Cover the container loosely with plastic wrap or a clear dome, which will help preserve moisture and warmth. As soon as any seeds in the tray begin to germinate, remove the plastic wrap and begin watering. Continue to keep soil throughly moist until most seeds in the tray have germinated.
Once seedlings have grown a half-inch or so, you should water less frequently, but begin fertilizing. Let the soil dry slightly between watering, which will help the seedlings develop a strong root system. Since many good seed-starting mixes do not contain adequate nutrients to carry seedlings through until transplanting, it is important to use a diluted (1/3 strength) organic fertilizer, like Neptune’s Harvest, when watering. Begin fertilizing two weeks after seeds have sprouted.
Seedlings will also need light and the best method is to use the traditional fluorescent fixtures or the new energy-saving LEDs. Suspend lights just an inch or two away from the plants. Lights must be on at least 14-16 hours a day, but off at night since seedlings also need a chance to rest. As your seedlings grow, raise the lights accordingly so they do not bump into the lighting fixture. If your seedlings do not get enough light, they will become weak and spindly. Gently rubbing your seedlings a few times a day with clean hands or a wooden dowel will also help strengthen stems. Thin seedlings if they become overcrowded, choosing the healthiest, strongest seedlings to save, and cutting the ones you are thinning with scissors. Pulling roots to thin can damage the roots of the remaining seedlings.
Hardening Off and Planting Out
When the weather is warm, move your seed trays outside gradually over a 5-7 day period. Start by putting them out just for a few hours during the late morning to mid-afternoon, and then gradually increase until they are left out all day and night. Keep them in a lightly shaded, protected spot during the day to prevent sunburn. After a week or two of this transition, gently transplant seedlings into the garden. Try not to handle the root ball too much, as they are quite fragile. Water thoroughly after transplanting and again every day for about a week. Newly set out plants will look sparse at first, but they will grow and fill in quickly, leading to bumper crops and a lush, delicious harvest!
Come by our Garden Center to check out all of our seed-starting supplies. Learn more helpful information. And lastly, don’t miss our upcoming Garden School Series class on Saturday, April 27, on seed starting warm weather crops.