Cultural Information for: Pageant, Danova, Bicolor, Delight, Daniella & Rosanna Annual
Common Name: Primrose
Botanical Name: Primula acaulis
Seed Count: 33,000 /ounce 1,150 /gram
Optimum Germination Temperature: 59-65°F / 15-18°C
Optimum Growing Temperature: 50-59°F / 11-15°C
Plug Culture – 8 weeks (288 12 x 24 tray)
Stage 1 (days 1-14) Select a sterile substrate containing
a high amount of organic matter and a pH between 5.5 – 5.8
and EC <0.6 mmhos (1:2 slurry). Primula seed requires
light for germination but a light cover of vermiculite is
recommended to maintain sufficient moisture. Optimum
germination temperature is 59-65ºF/15-18ºC. Temperatures
above 68ºF/20ºC reduce total emergence. Maintain high
humidity levels and if needed place the flats in a
germination chamber or shaded greenhouse to provide cool
Stage 2 (days 15-29) When the cotyledons are fully
expanded, target 65ºF/18ºC and lower the humidity level,
but do not allow the seedlings to dry out. A light mist 2-3
times per day is beneficial. Primula plants are very
sensitive and the leaves can easily burn in strong light
(>3,000 foot candles/32,000 lux). A light shade is
recommended to protect the plugs from intense sunshine.
During periods of high temperatures the plants grow very
slowly. Fertilize with 50-75 ppm N to strengthen the pl
Select a well-balanced calcium nitrate based fertilizer to
produce strong and healthy growth.
Stage 3 (days 30-48) The first true leaves have formed.
For high quality plugs it is necessary to maintain cool
temperatures and sufficient humidity. Fertilize the plants
with 100 ppm N as needed to maintain EC levels around 1.0
mmhos (1:2 slurry).
Stage 4 (days 49-56) The plants have 3-4 true leaves
and are now ready for transplanting. Applying 200 ppm N a
week before transplanting helps the plants make the
transition from the plug tray to the final container.
Transplant to Flowering – 84 (Pageant) to 112 (Daniella & Rosanna) days.
Pots: Transplant Pageant, Danova, Delight, Bicolor, Daniella and Rosanna plugs into 4-inch/10 cm pots using a well-drained sterile media. Optimum pH is between 5.5 -5.8.
Light Level: A maximum light level of 3,000 foot candles /
32,000 lux is recommended for Primula production.
Fertilizer: A well-balanced calcium nitrate based
Temperature: When the plants have 6-10 leaves and a
well-established, a frost free cultivation with temperatures
below 50ºF/10ºC is recommended to initiate flower buds.
Depending on the series, maintain this temperature for 4-9
weeks as prescribed below in the chart. When flower buds
are visible (but not before) the temperature can be
increased to 53-57ºF/12-14ºC to force flowering.
Schedule in Weeks Plug: 59ºF 15ºC Vegetative: 59ºF 15ºC Vernalization: 39 – 45ºF 4 – 7ºC Flowering: 53 – 57ºF 12-14ºC
Pageant* 8 4 5 3
Danova, Delight, Bicolor 8 4 7 3
Daniella, Rosanna 8 4 9 3
*For Pageant bicolors follow Danova schedule.
Production Points: In general, Primula is not attractive to insects, but aphids, thrips, white fly and cut worms are the major concerns. Problems with fungus gnats or shore flies are common during the germination and plug stage. Primula requires cool conditions and high humidity to
produce high quality plants which favors the development of
botrytis. Good sanitation, watering early in the day and good air movement helps control and prevent this disease.
Growth Regulation: In general, Primula growth is controlled with cool temperatures. If necessary, the following chemical growth regulators are effective. Do not apply below 41ºF/5ºC. To avoid over-regulation, multiple
applications at lower rates is best. Do not apply after flower bud set.
B-Nine (daminozide) 2,500 ppm/0.25% foliar spray
Bonzi (paclobutrazol) 5-10 ppm foliar spray
Bonzi (paclobutrazol) 0.5–1.0 ppm drench
Tilt (propiconazole)* 15-40 cc/100 liters foliar spray
Apply at 5 liters/100 m2
* apply as needed, but no more than 2 times per week.
“Information copied from the breeder.
Muller will not accept any liability for failure and/or damage as a consequence of incorrect and/or inexpert cultivation by or on behalf of the Buyer.”