Primula seedlings need light and air to germinate. Sow on the surface of the compost and do not cover with soil. Seeds which are slower to germinate ( double primroses, hose-in-hose, jack-in-the-green, auriculas and most of the species can be sown on a layer of vermiculite or very fine gravel over the compost. Water them in with a fine rose. Place a seed tray (perforated) of the same size over your sowings (to protect the seed when left outdoors) and weigh it down with a stone
Sowing: Sow seeds in late spring/early summer or late summer/autumn.
Primula seeds need a period of cold and damp to enable them to germinate. Sow from June onwards on a surface of seed compost, cover with grit and keep in a shaded cold-frame or cool glasshouse.
Sow seed 2.5cm (1in) apart in trays or cells containing seed compost. Sow the seeds on the surface of the compost, (Do not cover – they need light to germinate) and place in a light position at a regular temperature of around 16°C (60°F) Germination should take place between 21 and 40 days.
Primula seeds can also be sown during warmer times of the year, but it would be necessary to artificially simulate “winter” using the following method of “stratification”:
Place the seeds between two pieces of damp filter paper or folded kitchen roll then put into a polythene bag and place this into the fridge at 4°C (39°F) which is the temperature that most fridges are set at. Inspect the seeds after two weeks and remove as the seedlings appear, returning the ungerminated seeds to the fridge.