christyh said:Yes. Commercial seed mix. So, dry seeds are not correct? Should I have soaked them first?
Correct. For the chilling to break seed dormancy effectively the seeds need to have been re-hydrated to some extent. You can do this by various methods, soaking them for a day and then putting them on kitchen paper towels in a container in the fridge; just putting them in a baggie or container with a damp kitchen paper towel (or the pads some are using) and letting the seeds extract the moisture from the towel while in the fridge; or, my preferred method, putting the dry seeds into damp vermiculite, or damp sand, or damp perlite in either a baggie or other container in the fridge.
Leave them in the fridge for around four weeks and then take them out to room temperature to germinate, either still in the baggie/container or plant them in your starting medium.
Alternatively, before refrigerating you could plant them as you ordinarily would in damp medium of some kind, enclose that with a lid or baggie, and put the whole thing in the fridge. Then all you have to do is take them out after a month and set them somewhere at room temperature to germinate.
The purpose of damp chilling is to make them "think" they've been through a winter (fridge) and that it's now spring (room temperature) and therefore safe to germinate. If they're too dry through the fridge "winter" they can't respond to the cold temperature.
This damp chilling is called stratification, and once removed to room temperature the seeds should all germinate more or less together, usually within a few days. By a month after removal from the fridge they can be quite well grown.
Here are a couple of pics. The first one shows the test seedlings that were stratified in different types of media for comparison. They were one month in the fridge in the dampened media and this picture is taken a month after they came out to room temp. They were in the fridge in the little food containers. Once they started germinating at room temp I removed the lids. Left to right damp sand, damp perlite, damp vermiculite, damp coffee filter.
On the same day that I planted the above, I also set up two control experiments. The group on the left were planted in damp vermiculite at room temperature, never refrigerated. The ones on the right were refrigerated dry on a coffee filter for one month, then removed to room temperature and moistened. This picture was taken eight weeks after the start of the experiment. As you can see, far fewer seeds have germinated and they're way behind the damp chilled ones in growth.
I should add that the top ones are very crowded because this was just a numbers experiment and germination of the stratified seeds was in the 97% range. If being grown on to keep they would need to be separated and replanted, or have been sown more thinly. It's very easy to separate them if they're started in these types of medium. No fertilizer was used during the experiment and no seeds germinated while still in the fridge.
