RESUTLS RE: A STUDY USING WATER AS A MEDIUM TO COLD STRATIFY ROSE ACHENE (SEED): 8 WEEKS OF COLD STRATIFICATION IN A GLASS OF WATER OF 73 OP ICEBERG ACHENES.
Nine seedlings germinated out of 69 sowed (ie ~13% germination). The fist germination happened just past the three week mark from sowing, then there was a peak and then a drop off to the germination rate.
To summarise, these achenes were cold stratified in tap water in a sealed glass jar in the fridge continuously for 8 weeks, then 69 of these were sown in soil in a pot, outdoors in our spring. This spring turned out to be wetter than normal, but there have not been any unusual heat waves, which sometimes occur here this time of the year. The weather has fast approached summery conditions now, which is why I am calling it an end to the study now, in the belief that it is highly unlikely there will be more germinations as it is very warm now, some days are getting very hot.
I watered these achenes and the newly sprouted seedlings with a 10% NPK soluble fertilizer solution once every single day, from day 1 of sowing.
These 9 seedlings are doing ok, one has a partial photosynthesis defect, but seems to be “growing out of that”, (could it be virused, who knows??).
The weather this spring has been a rose hybridizer’s nightmare, totally unpredictable rainfall, dumping rain for some days in a row here and there, and overall very damp and humid. There has been a great deal of powdery mildew and blackspot everywhere.
I am happy enough to continue soaking rose achenes in refrigerated tap water in a jar, as my cold stratification system, I just can’t be bothered messing with baggies, moldy paper towling, peat etc etc.
I have no idea whether this method compares favorably or not to other more conventional methods of rose achene cold stratification, as I have never used any other cold stratification method to compare it with.