Starting flowers from seed both extends your gardening activities and provides a wider variety of plants than can usually be obtained from your local nurseries. Whether you choose to start seeds indoors or outdoors, starting seeds requires only light, water and soil, along with a little patient care. Expand your blooming season and garden repetoire by starting flowers from seed.
Starting flower seeds indoors
Select seed varieties you know will grow in your climate. Although almost any seeds can be started indoors, the test of their vitality is moving outdoors for the growing season. Specialize among tested varieties: fiery red marigolds, zinnias in only creamy shades, the tallest cosmos. Look for out-of-fashion biennials and perennials as your skill grows: delphiniums, hollyhocks and foxglove varieties that once graced local gardens.
Determine the last frost date in your area and plan to start seeds four to six weeks ahead. This ensures that seedlings will be strong enough to move to the garden.
Provide strong natural light or rig a grow light to provide a minimum of six hours of daylight to seeds. A sunny window under a covered radiator is ideal, providing both light and additional warmth to seeds. Ordinary indoor heating usually provides adequate warmth for seed growth; in a particularly chilly room, you may wish to explore electrical heating mats for seedlings.
Plant seeds in seed-starter mix or potting soil, usually 1/4 inch deep (unless seed package directions specify otherwise). Place two or three seeds in each pot or compartment. These light soil mixes promote healthy root development when starting seeds indoors.
Water seeds consistently. Soil should be kept moist, not wet. Tiny emerging seedlings can be watered with a teaspoon, to avoid damaging delicate roots and stems. Placing seed-starter pots on waterproof trays will both protect indoor surfaces and permit excess water to drain from soil.
Thin emerging seedlings, leaving the strongest in each pot or compartment. The small amount of soil in each pot or compartment of a seed tray will provide adequate nourishment usually for single plant.
Provide a transition period to move seedlings from indoors to outdoors. Move seedlings to a sheltered outdoor spot for a week before transplanting them into the ground. This period, called hardening-off, strengthens seedlings for seasonal growth.
Starting flower seeds outdoors
Prepare ground for outdoor seed-planting once your final frost-date has passed. Dig your flower bed to a depth of at least 6 inches, removing rocks and roots and breaking up large clods of soil. Rake ground smooth, and enhance its seed-growing potential by adding a 2- to 3-inch layer of potting soil. Dig 3-inch-deep drainage trenches between rows for seeds. If you prefer to broadcast your seeds (scatter them without making rows), dig a similar drainage trench around your seed bed.
Plant seeds per package directions, usually 1/4 inch deep in the soil. Cover with soil and tamp down gently but firmly (to lessen the chance that birds will make a meal of your seeds).
Water seeds consistently. As with indoor seeds, soil needs to be moist but not wet. In case of a very rainy spring or if you notice water pooling in your seed bed, increase the depth of your drainage furrows by an inch or two. Remember that the top layer of your bed dries first, so water as needed.
Thin seedlings once they have reached a height of 2 to 3 inches and have developed several leaves. This will promote the growth of your strongest plants. Remove less viable seedlings gently, to avoid damaging the roots of still-fragile stronger plants. Tamp down soil around remaining seedlings.