Q: Last year I sowed polyanthus and winter-flowering pansies. The pansies germinated well but the polyanthus were a disaster. I treated both in exactly the same way – what was the problem?
A: That is probably where you went wrong, because although both are grown in virtually identical conditions, there is one big difference.
Sowing seed for next spring’s polyanthus and winter-flowering pansies is normally done in June. Both need a reasonable, moist compost and a small amount of heat to help them to germinate – 60deg F should do fine. But whereas the seeds of the pansies need darkness to encourage them into life, those of the polyanthus do not.
So, cover the seeds of the pansies with compost but simply sprinkle the very fine seeds of the polyanthus on the surface of the compost because they need light to help them germinate. They also take quite a while to grow until they flower. Once the seeds have been sown in their trays or pots, cover the containers with cling film. When the seedlings appear, wait until they are large enough to handle before potting them up until it’s time to plant outdoors, in autumn, where you want them to eventually flower.
So, keep pansy seed in the dark, but with the polyanthus – let there be light. Hopefully, spring 2017 will then be a lot more colourful.