Patience is a must when working with plants, but sometimes you just need a quick splash of color -- especially if you are a beginning gardener or if you are helping a child learn how to plant and grow seeds. In such cases, reach for fast-growing flower seeds to sow and reap your rewards quickly.
About Growth Rates
Defining a plant's rate of growth can be tricky, because some define growth as the time it takes for a plant to reach maturity, while others might define it as how much new growth is produced in a year. When it comes to seeds, growth is usually defined as the time from germination to flowering. Some flowers, such as zinnias (Zinnia spp.), which are annuals, germinate quickly, but take a long time to flower. Others take a long time to germinate but flower shortly after that. Plants with seeds that germinate quickly and flower a short time after that are considered fast growing.
Short and Sweet
Coleus plants (Coleus spp.) are not often grown from seed, but they do germinate easily and quickly -- in about eight days, and they bloom around 45 days after that. An annual plant that reaches a maximum height of about 3 feet, coleus are prized for their colorful foliage over their flowers, which shows up even sooner than the flowers do. Another fast-growing plant, phlox (Phlox spp.) is best known for its star-shaped flowers. Hardy in U.S. Department of Agriculture plant hardiness zones 2 through 9, the plant reseeds itself readily, germinates in five to 10 days and blooms as soon as 50 days after germination.
When it comes to fast-growing flowers that sprout easily from seed, you can't overlook -- literally -- the majestic sunflower (Helianthus spp.) In general, annual sunflowers germinate in one or two weeks and bloom around 50 days later. Dwarf varieties tend to bloom a bit earlier than other varieties. Sunflowers need full sun and well-drained soil to thrive. Scarlet runner beans (Phaseolus coccineus) tower in a different way -- they climb quickly and easily up a trellis or fence to heights of 12 feet or more. These annuals are prized for their bright flowers and edible seedpods. Scarlet runner beans germinate quickly -- in four to seven days -- and are ready to harvest as early as 45 days later.
Annual marigolds (Calendula officinalis) grow quickly and grow from large, easy-to-handle seeds. They germinate in between four and seven days and bloom around 50 days later. The wide range of colors and sizes makes it easy to find one to suit any garden, and annual marigolds grow in any USDA zone. They grow best in well-drained soil and in full sun. Nasturtiums (Tropaeolum spp.) are often the go-to choice for teachers who want to show their students how quickly flowers can grow and bloom from seed. They germinate within two weeks and bloom about 55 days later. Another flower that has large seeds, nasturtiums are annual plants and will even grow in poor or dry soil, although they prefer well-drained soil and sunny conditions.