California Giant, Zinnia Seeds

California Giant Zinnia Seed

Five-inch dahlia-style flowers crown sturdy three-to-four-foot plants
Bouquet-ready California Giant brightens sunny borders
Deadhead California Giant regularly for more flowers
Warm-weather California Giant grows quickly from seed

See product details

Key Attributes

Botanical Name

Zinnia elegans

Days to maturity

80 Days

Sun

Full Sun

Packet

100 Seeds

About California Giant, Zinnia Seed, Zinnia Seed

California Giant Zinnias are a classic heirloom flower variety developed for their impressive size and vibrant color range, including red, pink, orange, yellow, white, and purple blooms. These zinnias produce large, dahlia-like flowers up to 5 inches across on sturdy stems that can reach 3–4 feet tall, making them a standout in garden beds and floral arrangements. Easy to grow and highly productive, they thrive in full sun and well-drained soil, and should be sown directly after the last frost or started indoors 4–6 weeks earlier.

Growing details

Planting

Sow Depth

1/4"

Days to Germination

3–7 days

Germination Type

A - No Pretreatment

In-row plant spacing

9-18"

Plant profile

Life Cycle

Annual

Plant Height

48 inches

Growth Habits

Upright

Seed & variety

Seeds Per Ounce

4,250

Color

Multicolor

Seed Type

Heirloom

Before Planting

For Zinnia, select a full-sun site with well-drained soil and good air circulation. Remove perennial weeds, loosen compacted ground, and incorporate modest compost without making the bed overly rich. Prepare a fine, firm seedbed. No seed pretreatment is normally required; use fresh seed and follow the sowing conditions in the Planting guidance.

Planting

Direct sow zinnias after frost danger has passed and the soil has warmed, or start them indoors only 3–4 weeks earlier. Maintain about 70–75°F and even moisture until germination, then provide strong light and airflow. Harden seedlings gradually and transplant without excessive root disturbance. Space dwarf zinnias about 6–9 inches apart and tall branching types 12–18 inches apart.

Watering

Zinnia needs consistent moisture during establishment but tolerates moderate dryness afterward. Water deeply during prolonged drought, allowing the upper soil to dry between applications.

Fertilizer

Zinnia needs only moderate feeding. Use diluted balanced fertilizer during active growth, following label rates and limiting nitrogen so plants remain compact and flower freely.

Harvesting

Harvest zinnia as buds begin opening or when blooms reach full color, depending on intended use. Cut above a branching point, place stems in water promptly, and remove spent flowers regularly.

Tips

Pinch young zinnias above several leaf pairs to encourage branching and longer stems. Deadhead regularly, support tall varieties, and maintain generous airflow to reduce foliar problems.

Pests & Diseases

Powdery mildew, Alternaria and bacterial leaf spots, Botrytis, and white mold affect zinnias. Choose resistant varieties, space plants generously, and water at soil level. Remove spotted lower leaves and entire plants with cottony stem growth or black sclerotia. Do not save seed from diseased flower heads.

Monitor zinnia for aphids, thrips, mites, beetles, slugs, and chewing caterpillars. Remove badly infested growth, use physical controls first, and apply labeled treatments outside pollinator-active hours.