Starting flowers indoors is an inexpensive way to expand your flower garden varieties. There are different types, colors and sizes available as seeds. Several flower varieties need a head-start on the growing season to blossom in the summer. Starting flowers inside occurs four to 12 weeks before the last spring frost. Start geraniums, pansies and violets in the first couple of weeks of February. Hollyhocks, marigolds and phlox are started in mid-March and cosmos, sweet Williams and zinnias are started in mid-April.
Disinfect the plastic cell plant pots by soaking them in a mixture of 1 part bleach and 9 parts water for 30 minutes. Do not use a large tray because the seedlings' roots will tangle with each other and suffer damage when you separate them for transplanting. Poke holes in the bottom of the cells if there are no drainage holes.
Mix together equal parts of vermiculite and peat moss. Fill the cells with soilless planting mixture and sprinkle the mix with water. Let the mixture settle, then top off with more mixture and water again.
Follow the seed packet directions and plant the seeds at the proper depth. One rule to follow is to plant seeds four times as deep as the seed's width. Cover the seeds with a layer of vermiculite. This lets light in and keeps the moisture in. Spray the seeds with a fine mist of water.
Cover the seeds with several layers of damp newspaper, if the seeds need darkness to germinate. For seeds that need light, cover the plant pots with clear plastic to create a greenhouse effect.
Remove the coverings when the seedlings are tall enough to touch the cover. Keep the seedlings moist by spraying them with lukewarm water. Wait until the last frost has passed to transplant your seedlings outside.