Growing Zinnias from seed
Zinnias are one of the easiest and most rewarding flowers to grow, offering a burst of color and charm to any garden. Whether you’re planting them in beds, containers, or for cut flowers, zinnias thrive with minimal effort and deliver vibrant blooms all season long. Follow this guide to sow, grow, and enjoy these delightful flowers.
Sowing Zinnia Seeds
Zinnias should not be sown too early. Typically, sowing at the beginning of April is sufficient, or adjust the sowing time so that transplanting into the ground coincides with the end of night frosts. It takes about 9 weeks from sowing to blooming.
Sow zinnia seeds directly into pots or seed trays using soil suitable for sowing. Cover the seeds lightly with a thin layer of soil or vermiculite. To speed up germination, cover the seeds with a light plastic lid or plastic wrap with air holes to prevent them from drying out. The optimal germination temperature is 20–22°C. Once the first leaves appear, remove the plastic cover to avoid the harmful effects of condensation, which can damage the young leaves.
After germination, the soil should be kept evenly moist but not overly wet. It is recommended to water the plants from below to maintain soil moisture without harming the seeds. Excess moisture is one of zinnia's weaknesses, as it can lead to seed rot or other diseases, which can quickly damage the young plants.
When the seedlings develop more leaves, transplant them into larger containers or pots with quality soil. At night, lower the temperature to about 15°C, and place the seedlings in a well-lit location to prevent them from becoming leggy. If the seedlings cannot be kept in a greenhouse or on a veranda, consider additional lighting. Continue watering from below, and after a few weeks, you can start using a mild fertilizer.
To encourage bushier growth, it is recommended to pinch back the tops of the zinnia seedlings. This promotes branching and creates more flower stems. Before planting them in the ground, harden off the seedlings by gradually exposing them to outdoor conditions. A week before planting, place them outdoors in a shaded area during the day and bring them back indoors at night. Initially, cover the seedlings with horticultural fleece to protect them from wind and temperature fluctuations.
Zinnias are very sensitive to frost and thrive best in sunny, warm, and wind-protected locations. If you are growing zinnias in pots, they can easily be moved to sheltered areas if temperatures drop unexpectedly during summer.
With proper care, zinnias will delight you with abundant and long-lasting blooms throughout the season!
Direct Sowing in the Ground
Zinnias can also be sown directly into the ground once the soil is sufficiently warm. This is especially suitable for southern regions of Latvia, where direct sowing can be done earlier. Choose a sunny spot with well-prepared, loose, and weed-free soil. Direct sowing is an excellent alternative if you want to avoid the process of transplanting seedlings.
