Sow Cold Germinators in Autumn
Cold germinators are still referred to as frost germinators, although is isn't quite correct, because they need a period of low temperature to break dormancy.
The sowing of cold germinators must be kept warm (about +18 to 22°C) (about 64 to 72°F) and moist for the first 2-4 weeks. After this period the sowing must be kept at a cold temperature (between -4 and +4°C) (between 25 and 39°F) for another 4-6 weeks. It is not so important if the temperature is higher of lower during the cooling period, but the cooling period has to be prolonged because the synthesis of the germination inducer, homonlike acid, slows down or comes to a standstill.
It is beneficial to cover the sowing with snow during the cooling period. After this cooling period the sowing may not be immediately exposed to high temperatures. The most effective temperatures are between +5 to 12°C (41 to 54°F), even if germination has started. The best location for this sowing, even in March, April and May, is open field, the cold frame or a cold greenhouse.
In the nineteen seventies Klaus R. Jelitto developed a new procedure for systematically eliminating the natural seed dormancy for cold germinators. JELITTO GOLD NUGGET SEED® make it possible for cold germinators to germinate quickly and uniformly without cold treatment as described above. Please have a look at Storage and Sowing directions of GOLD NUGGET SEED® or our JELITTO GOLD NUGGET SEED®-webpage.
More on Cold Germinators"You can't hurry love; You just have to wait" - The Supremes
Sometimes the expected warm/cold period does not produce the anticipated results. Some perennials will need a longer time until germination begins. Sometimes, an additional cold period concluding the following Spring is necessary. Do not hastily discard seed trays too early. Gentiana verna is a good example.
This can be avoided by choosing JELITTO GOLD NUGGET SEED® for faster germination on a growing number of species which have proved slow-to-germinate by standard means.