Zinnias are popular flowering annuals because they are easy to grow and maintain. A packet of zinnia seeds will provide months of colorful blooms from spring till frost. You can choose from numerous colors and flower types of zinnias to fill in the blank spaces of your garden or to use in containers.
Sow zinnia seeds outdoors after the predicted date of the last frost. Choose an area in full sun with rich, well-drained soil. Sow zinnia seeds indoors 4 to 6 weeks before the predicted date of the last frost. Fill small pots with fine textured potting soil.
Use a pencil to make holes ¼ deep for small seeds. Space the planting holes according to the directions on the seed packet.
Put three seeds in each hole and cover lightly with soil. Water thoroughly with a water hose or a watering can. If planting indoors, set the pots in a bright warm location. Zinnias germinate in 5 to 7 days.
When the seedlings are 6 inches tall, remove the two weakest plants from each group of three. You can also cut off the two weakest plants at ground level with gardening snips.
Set the potted seedlings outside in the shade for a few days after the predicted date of the last frost to harden off.
Transplant the seedlings into an area with well-drained rich soil in full sun. Use a trowel to dig a hole deep and wide enough to hold the roots of a plant without breaking or squeezing them. Space the planting holes according to the directions on the packet for the variety of seeds you are using.
Set the plant in the hole and push the soil back into the hole with your hand. Lightly tamp the soil around the plant, but do not mound the dirt up around the stem of the plant. Water thoroughly with a water hose or watering can.