While you may be tempted to purchase grown annual plants for your Massachusetts garden this spring, the least expensive seasonal color comes from those you start from seed at home. A tray will with potting soil and a warm, bright indoor window allows you to start seeds four weeks before the last spring frost date and then transplant them outside to fill the garden beds. Seeds also may be directly sown outdoors in successive plantings so continual new bloom occurs in waves over summer.
A wide array of zinnia (Zinnia spp.) hybrids exists, offering you a broad choice of flower colors, shapes and mature plant heights. With large seeds that quickly germinate, be assured you can grow lots of plants with a few inexpensive seed packets. The bushy species with the widest selection of varieties is Zinnia elegans. Choose from tall-growing types like those in the California Giants series, or short, petite types suitable for containers or the front of the bed like the Thumbelina or Dreamland series.
If you love butterflies and boldly colored flowers, choose the cosmos (Cosmos spp.) to grow easily from seed. White, pink, burgundy and crimson flowers grow upon selections of species Cosmos bipinnatus, while hot reds, oranges and yellows comprise the species Cosmos sulphureus. All cosmos relish sunshine and heat, so plant seeds every two weeks so plants continually flower across the season.
Annual sunflowers (Helianthus annuus) grow both above your head, while smaller varieties that mature to waist height. Big seeds make sowing easy and their fast growth draws excitement. Use shorter varieties if you live in a windy location and if you don't want to stake plants.
Clothe a vertical post or fence by planting morning glory vines (Ipomoea purpurea). Nick the seed coats and soak in water overnight before sowing them in warm soil. Enjoy their morning-opening trumpet-like flowers all summer long in shades of purple, indigo, blue, pink or white.
Marigolds (Tagetes spp.) release a pungent scent from the leaves, often discouraging animals and insect pests from the flower border. Easily grown from seed, which looks like a tiny beige and black plume, taller growing types are usually called French marigolds while compact, small plants named African marigolds. Most are hybrids, but offer flowers in color ranges from nearly white to yellow, gold, orange and rusty red, and multicolored combinations.