Hoe zaai je koude kiemers in de volle grond - korte instructies en tips

1. Uitleg van begrippen: Wat zijn koude kiemers?

Koude kiemers, ook wel vorst kiemers genoemd, zijn planten waarvan de zaden door een koude fase moeten voordat ze ontkiemen. Deze planten hebben speciale kiemremmers die alleen worden afgebroken door de invloed van lage temperaturen gedurende meerdere weken. Pas na deze koude stimulans zijn de zaden klaar om te ontkiemen wanneer de temperaturen in de lente stijgen. Deze aanpassing voorkomt dat de zaden te vroeg in de herfst ontkiemen en verloren gaan door vorstschade.

2. De beste tijd om te zaaien

De ideale tijd om koude kiemers te zaaien is laat in de herfst tot vroeg in de winter, meestal tussen november en januari. Tijdens deze periode zijn de temperaturen laag genoeg om de nodige koude prikkels te geven. De zaden hebben dan genoeg tijd om door de koude fase van de winter te gaan, zodat ze optimaal kunnen ontkiemen in de lente wanneer de temperaturen stijgen.

3. Factors to consider when sowing

When sowing seeds that need cold to germinate there are a few key points to consider:

Pots rather than direct sowing: We recommend sowing seeds that need cold to germinate in pots or seed trays. Many plants that need a cold phase also need light to germinate. These are often very tiny seeds that are easily blown or washed away. If they’re sown in pots these problems are easier to manage – and pots are more easily moved around, too.
Substrate and location: Use a free-draining, humus-rich substrate and make sure it’s finely textured, so that your tender seedlings can develop optimally. A semi-shade location is ideal, so that the soil doesn’t dry out but your seeds still get enough light.
Protection from animals: Covering your potted seeds with a fleece, a fine wire mesh or a net will protect them from animals – mice and birds will be delighted to help themselves to your seed in winter. It’s important that this protection should be breathable to prevent moisture build-up and allow the cold to reach your seeds.
Creating the cold phase: When the seeds are first sown they initially need a short period (2-4 weeks) at temperatures between +5 and 15°C – so it might be best to place the pots in a greenhouse or in a cool location like a staircase or landing to start with. After this, though, they should be placed outdoors during the winter so that they go through their natural cold phase. Sowings work even better if the pots are set into the ground in a free space in your garden. All in all what’s needed here is patience: most plants that need a cold phase won’t germinate until spring when the temperatures start to rise again.