Primula plants need light and air to germinate. Sow on the surface of the compost and do not cover with soil. Seeds that 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 with a fine rose Place a seed tray (perforated) of the same size over your seeds (to protect the seed when left outside) and weigh it down with a rock.
Leave the plot in a shady place outside. Inspect regularly and water as needed. Do not let the compost dry out. As soon as the seeds sprout, remove the cover. Protect against snails. Polyanthus and primrose germinate within three weeks. Auriculas is slower and Sieboldii can take six weeks. Most of the species need natural freezing and thawing to get them going so it is important that as early as possible.
Keep the seeds cool and moistHigh temperatures inhibit germination. Dehydration – especially at the moment of germination – is usually fatal. Do not plant your seeds under glass, as the temperature rises too high on sunny days, – even in winter!! Ideal germination temperature is between 12 and 15 degrees Celsius. Lower temperatures do no harm, but anything above 18 degrees is fatal. NEVER use a heated propagator.