Primula product range of Schoneveld Breeding

GERMINATION

Sow seeds in plug trays filled with a fine textured peat mix with an EC between 0.7-0.9. It is not necessary to cover with vermiculite unless maintaining moisture is a concern. During germination, maintain moderate moisture levels, being careful to not allow seeds to dry out or become saturated.

Temperatures of 59-64°F (15-17°C) are suggested during germination to improve uniformity. Starting in a germination chamber can be useful during this period and increase germination rate. Seeds should germinate in 7-10 days.

Once germinated, temperatures can be increased to 61-65°F (16-18°C) and soil moisture can dry slightly between watering.

Once true leaves are present fertilization can be applied at 75-to 100- ppm nitrogen every third watering or 50 ppm of a well balanced water soluble each watering is recommended.

pH should be maintained at 5.5-6.2.

Primula are sensitive to high light levels. To prevent burning, provide 30-50% shade when natural light levels exceed 3,000 f.c.

The plants are ready for transplant when they have at least 4 developed leaves. Plugs should be ready to transplant app 6-7 weeks after sowing.

TRANSPLANT

Fill the pots to the rim with well aerated potting compost enriched with lime and fertilizer, pH 5.8 – 6.0 and EC 0.8 – 1.0 mS/cm. Make sure that the plugs are sufficiently moist and planted even with the medium. Planting too deep can result in crown rot.

CLIMATE

Temperature: During the first 10 weeks maintain the temperature at 50-57ºF (10-14ºCº), then gradually lower the temperature to no less than 37ºF (3°C). The plants need a cool temperature for proper finishing. This is especially relevant for the late series of Paradiso.

It is suggested to maintain your relative humidity at 60 – 80%. In all circumstances, ensure there is an active climate via ventilation by using fans or setting the heating pipe to a minimum temperature.

Lighting: The first 2-3 weeks after transplant, set the light levels to 450 – 500 W/m² (40 – 44 Klux). As soon as the roots are visible at the edge of the pot, gradually increase the light levels to 500 – 650 W/m² (44 – 61 Klux). You may need to use a movable screen, net or chalk the greenhouse roof depending on your conditions.

WATERING

After transplant, water the plants from above for the first few weeks (moisture level 3 – 4) to encourage good growth and a good microclimate. It is a good idea to water in the mornings so that the crop is dry before nightfall.

As soon as the first roots are visible at the edge of the pot, the plants can be grown under dryer conditions (moisture level 3).

As well, when first buds are visible, it is preferable to water from below.

FERTILIZATION

During the first 6 – 8 weeks use an NPK fertilizer including trace elements with an N:K ratio of 1:2, add calcium and iron (EDDHA) to the fertilizer regularly. Depending on the growth, adjust the N:K ratio to 1:3 or 1:4.

Aim for an EC of 0.5 – 0.7 mS/cm in the pot.

Also, monitor your nutritional status in the pot by taking soil samples once every 4 to 6 weeks.

GROWTH REGULATION:

Growth can be regulated by timely fertilization with additional potassium (more K). As well,  keeping the plants a little dryer or by applying a temperature drop are a couple other methods of maintaining plant size.

If necessary, chemical growth regulators Dazide and Propiconazole may be used.

CROP PROTECTION

Here are a few pests and diseases that may damage your Primula acaulis crop:

• Botrytis
• Bacteria pseudomonas or acidovorax
• Ramularia primulae (leaf spot disease)
• Thielaviopsosbasicola
• Mycocentrospora
• Whitefly
• Leaf miner
• Caterpillars
• Fungus gnats (Sciara)
• Thrips
• Mites

Apply preventive measures regularly.

Note: All information provided in these growing recommendations has been carefully compiled from our own observations and internal trials in Northern Europe. For culture information for the primula polyanthus, primula obconica or other Schoneveld genetics please contact Kathy McKay.