Can I Plant Zinnias in Pots?

Choosing the Right Container

• Annual plants grow, flower and produce seed in a single season before dying back with the first frosts. Zinnias are annuals so there is is no need to overwinter them indoors. Plant zinnias in the spring in large patio pots or in window boxes. A half-barrel planter works well or get creative with painted buckets, coffee cans or simple terracotta planters. The only thing required of a good planter is that is has drainage holes in the bottom. A planter should have multiple holes 1/2 to 1 inch around or one larger hole in the center. The holes in the bottom allow water to drain through keeping the roots moist but not too wet during the growing season.

Potting Soil Mix

• Growing zinnias successfully in containers requires the right potting mix. Purchase a soil-less potting mix from a home and garden center if you are only potting up a few small planters. For larger projects, save money by making your own soil-less potting mix. Combine equal parts sphagnum peat moss or coconut coir, perlite or vermiculite and coarse clean sand. Fill the zinnia planters with the soil-less planting mix. Garden soil is not well suited for growing zinnias in containers as it tends to drain poorly and contain microbes that cause root rot.

Spacing and Planting

• Plant zinnias in large outdoor containers in spring after the last frosts pass. In smaller indoor containers, plant zinnias any time in late winter or spring. Zinnia starts or seedlings show up at garden centers and markets in spring, commonly in cell packs or 2-inch containers. Plant small varieties that grow 8 to 12 inches tall 4 to 6 inches apart. Space larger varieties 8 to 10 inches apart. Place zinnia containers in a bright sunny spot. Fill and plant large planters in their permanent location. Once full of soil mix and flowers, planters get heavy fast.

Container Care

• Container care differs somewhat from garden bed care. Planters dry out faster than garden soil and some planters dry out faster than others depending on the material. Terra cotta pots and wood pots dry out faster than metal and plastic so check them often. Water zinnias when the top 1/2 inch of the soil dries out to keep the pots evenly damp throughout the growing season. Check the pots frequently during hot, dry weather. Fertilize zinnias once a month using a water soluble flower food fertilizer.