Grower Facts

Coreopsis Grandiflora (Coreopsis grandiflora)

Germination：Use a well-drained, disease-free, soilless medium with a pH of 5.8 to 6.2 and a medium initial nutrient charge (EC) of 0.50 to 0.75 mmhos/cm (1:2 extraction). Cover the seed with a light layer of coarse grade vermiculite. This helps in keeping the seed moist during germination. Light is required for germination. Allow 4 to 6 days for germination.

Plug Production

Plug Tray Size
- Early Sunrise, Rising Sun, and Sunfire coreopsis plugs are best produced in 392-cell plug trays.
- The average plug production time is 5 weeks.
Media：Use a well-drained, disease-free, soilless medium with a pH of 5.8 to 6.2 and a medium initial nutrient charge (EC) of 0.50 to 0.75 mmhos/cm (1:2 extraction).
Sowing：Cover the seed with a light layer of coarse grade vermiculite. This helps in keeping the seed moist during germination. Light is required for germination. Allow 4 to 6 days for germination.

Temperature

Germination: 68 to 72°F (20 to 22°C)
After Germination: Plugs can be grown in the greenhouse at 70 to 75°F (21 to 24°C) days and 60 to 65°F (15 to 18°C) nights until transplant.
Light
Stage 1: Light is required for germination
After germination: 2,500 to 3,000 f.c. (25,000 to 30,000 Lux)
Seedling maturity: Up to 5,000 f.c. (50,000 Lux)
Humidity：Maintain 95 to 97% relative humidity during germination.
Soil Moisture：Keep soil moisture high at radicle emergence, then reduce moisture levels after cotyledon development. Do not allow seedlings to wilt.
Fertilizer：When cotyledons fully expand, start fertilizing with 50 ppm N twice a week. As the true leaves develop, increase the fertilizer rate to 100 ppm N. Maintain the plug media EC at 0.75 to 1.0 mmhos/cm and pH at 5.8 to 6.2.
Plant Growth Regulators：Not required.

Growing On to Finish

Container Size：4-in. (9-cm.) or 6-in. (15-cm.) pots
Media：Use a well-drained, disease-free, soilless medium with a pH of 5.8 to 6.2 and medium initial nutrient charge.
Temperature：Night: 55 to 60°F (13 to 15°C)，Day: 60 to 70°F (15 to 21°C)
Maintain these temperatures until bud initiation.
Light：Coreopsis flowers earlier under long days. Provide night interruption lighting (10 p.m. to 2 a.m.) when grown under short days.
Irrigation：Maintain even moisture. Avoid excessive wetness.
Fertilizer：After transplant, fertilize the crop with a well-balanced fertilizer supplying 150 to 200 ppm N. Maintain the media EC at 1.50 to 2.00 mmhos/cm and pH at 5.8 to 6.5.

Plant Growth Regulators：Growth Regulators can be applied for container production. Foliar sprays of B-Nine at 5,000 ppm applied twice after transplant work well. First application can be done 2 weeks after transplant followed by a second application 2 weeks later. In regard to the plant height at flowering during pack/ container production, Rising Sun flowers more compact, Sunfire flowers slightly taller than Rising Sun, and Early Sunrise flowers the tallest of all the three. Hence, Rising Sun & Sunfire needs less PGR applications compared to Early Sunrise.

Crop Scheduling

Sow to transplant (392- cell plug): 5 weeks
Transplant to finish in a 4-in. (9-cm.) pot: 8 to 10 weeks
Transplant to finish in a 6-in. (15-cm.) pot: 9 to 10 weeks
Total crop time from sow to finished container: 13 to 15 weeks
The timing is dependent on the temperature and light provided. Sunfire flowers at the same time as Rising Sun and both flower a week to 10 days earlier than Early Sunrise.

Common Problems