Growing Indoor Zinnias: Caring For Zinnias As Houseplants

Small Potted Yellow Zinnias
(Image credit: Mark R Coons)

Zinnias are bright, cheery members of the daisy family, closely related to the sunflower. Zinnias are popular with gardeners because they’re so easy to get along with, even in climates with long, hot summers. Like many summer-blooming flowers, zinnias are annuals, meaning they germinate, bloom, set seed, and die in a single year. They typically aren’t well-suited for the indoor environment, and the idea of zinnias as houseplants may not be realistic.

However, if you’re interested in trying your hand at indoor zinnias, go ahead and give it a shot. Potted zinnia flowers may live a few months indoors, but don’t expect zinnias as houseplants to survive indefinitely. Here are some tips for indoor zinnia care.

Indoor Zinnia Care

Although you can grow zinnias from seed, it’s easiest to start with small bedding plants from a garden center or nursery. Look for dwarf zinnias, as regular varieties can become top-heavy and may tip over.

Plant in a container filled with good quality potting mix. Add a generous handful of sand to improve drainage. Be sure the container has at least one drainage hole in the bottom, as the plants won’t last long in soggy growing conditions.

Outdoor zinnias get plenty of bright, natural sunlight, and even your brightest window may not provide enough light. You’ll probably need a high-intensity grow light, or a regular two-tube fluorescent fixture with one cool tube and one warm tube.

Water indoor zinnias whenever the top inch (2.5 cm.) of soil feels dry to the touch. Be careful not to overwater, and never let the pot stand in water. Fertilize potted flowers every other week, using a dilute solution of a water-soluble fertilizer.

Zinnias as houseplants will last longer if you deadhead blooms as soon as they wilt. Use shears or clippers, or just pinch the blooms with your fingernails.

Mary H. Dyer

A Credentialed Garden Writer, Mary H. Dyer was with Gardening Know How in the very beginning, publishing articles as early as 2007.