Common Name | Zinnia |
Genus | Zinnia |
Species | Z. elegans, Z. haageana, Z. peruviana |
Family | Asteraceae |
Life Cycle | Annual |
Tray Size | 210 |
Plug Care | Zinnias are fast growers and will quickly become rootbound in the plug trays if not planted out soon after arrival. |
Netting / Staking | Not absolutely necessary but 1 or 2 layers of support can be helpful. |
Temperature Range | Extremely frost sensitive - zinnias like it hot and sunny, so wait until the threat of frost has passed, the soil has warmed up and temperatures stay consistently above 55F at night. |
Spacing | Minimum 8-12" depending on variety. |
Soil Preference | Well drained, fertile soil. Neutral to slightly acidic pH for best results. |
Day Length | Facultative short day (Zinnias can still flower under long day conditions but are most floriferous when the day length shortens). Plant zinnias in full sun. |
Pinching | One pinch is recommended when the plants are about a foot tall - pinch down to three or four sets of leaves to promote side branching. |
When to Plant | In the spring after all threat of frost has passed and the soil has warmed. |
Harvesting | Expect the first flowers approximately 60-80 days after planting. Harvest flowers when fully open and when the stem is stiff. If the flower wobbles from side to side when the stem is wiggled, it is not fully mature and the vase life will suffer. Zinnias are a cut and come again plant - expect many stems over a long flowering window. |
Post Harvest Care | Place into cool water immediately after cutting. Cut zinnias benefit from a cvbn tablet or a couple drops of bleach in the water to increase vase life. Do not store zinnias in a cooler as they are cold sensitive and the petals will brown (store at or above 50F). |
Diseases / Insects | Zinnias have a reputation for developing powdery mildew and alternaria leaf spot, especially later in the season. Increasing airflow between plants and keeping foliage dry when irrigating can help slow the spread of these diseases. Zinnias have few insect pests. |
Bailey's Notes |
Zinnia plugs may bud early due to becoming rootbound. Deadhead all flowers as they fade to promote continuous flower production. Seed development saps a lot of energy from the plant and productivity will decline. |
Resources |