So they must be given a head start indoors. Growing plants from seed is not difficult, although it does require a fair bit of time and space. Try to provide as much light as possible for the young seedlings by placing the trays close to a south facing window. Warm the soil by placing the seedling tray on a heat register or on a heating cable. As soon as the seedlings emerge, they should be removed from the heat but remain in a bright, sunlit area.
Plants vary greatly in their intervals from seeding to maturity.
As a general rule, the smaller the seeds, the longer the plants take to grow, and the more difficult the seed is to handle. Always read the instruction on the seed packet prior to sowing. High quality seed usually comes complete with germination information. This information is critical to the success of many species, particularly perennials. With perennials, keep in mind the length of time before the plant will bloom.