Primula product range of Schoneveld Breeding

There are several types of primula available in today’s garden centers. Primarily known as a cool season plant, primula is versatile for indoor and outdoor use. With longer shelf life, improved uniformity and a whole range of colors, it is a wonderful addition to a program.

Schoneveld Breeding is focused on developing and producing quality primula seeds of acaulis, polyanthus, and obconica types. Features such as genetically superior plant structure, uniformity, aesthetically appealing blooms and colors as well as sustainability are key components.

Here are the main attributes of each type of primula to decide which series is best for you.

*This article is based on the North American situation

Primula acaulis – environmentally friendly to cultivate

Primula acaulis Paradiso is a series which is environmentally friendly to cultivate. With this series, the amount of growth regulators is reduced. Less growth regulator is better for the environment and saves money. Furthermore, the grower has greater control of the crop.

Primula acaulis Paradiso is available in 4 types:

  • Paradiso Early: suitable for early season. Requires little to no cool treatment.
  • Paradiso Mini: compact growing Primula acaulis. Great for 3” pots.
  • Paradiso Mid: can be grown with less growth regulator and is less susceptible to leaf yellowing. Suitable for early to mid season shipping. Requires minimal cooling.
  • Paradiso Late: These varieties have a good shelf life and uniform blooms. Great for late and extended season programs for spring. This series does require cool treatment to flower.

Primula obconica – Primin Free

Primula obconica Touch Me (Primin Free) is a true spring plant with beautiful firm, bright green leaves and cheerful flowers. It comes in both soft tints and truly vibrant colors to give you a really glorious touch of spring. Together with the new flowers which are lighter in color this creates a very special effect.

The Touch Me is also ideal for use in 3”-6”/gallon pots.

  • Touch Me Mini: genetically small compact plant, suitable for pot size 3-4”.
  • Touch Me Midi: firm flower stems, cheerful colours and a long flower life.
  • Touch Me Large: a strong plant with a genetically compact structure.
  • Pricanto: Primula Pricanto has magnificent vintage coloured flowers with a nostalgic edge.

Original: this is the only Primula obconica from Schoneveld that does contain Primin, giving the plant natural resistance to insects.

Primula polyanthus – longer shelf life than acaulis

Primula Perola is a polyanthus type. This long-stemmed Primula is characterized by its exceptionally strong stems which prolong the flower life. Primula Perola (polyanthus) has a longer shelf life than the standard Primula acaulis. It has a more open structure and higher production of flower stems (compared to acaulis) making Perola less sensitive to botrytis.

All of these series are developed with both the grower and consumer in mind for success.

About Kathy McKay

Kathy McKay is the area manager for North America with Schoneveld Breeding. She can be reached at  kathymckay@schoneveld.nl.

ACAULIS GROWING RECOMMENDATIONS

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.

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