Would be nice if they offered some kind of key or explanation at all.
I also did a web search and don’t see what these periods are supposed to refer to?
Is it something that one is expected to know in the Americas so they feel no need to explain? I have never heard of it here in the UK and a seasoned orchardist also from the UK who replied to one of my comments also said they had no idea what they meant either.
Ye I was trying to backwards engineer it by looking at apples which which i know the general ripening time, to try and figure out the pattern but there seemed little rhyme or reason!
Also as to accuracy, the post I linked recently where the lady stored her Yellow Transparents for 14 months, which she applauds as one of the best keepers, yet pomiferous state it is only good for 2 months, yet have many others with higher keeping times.
I spent days painstaking going through all the apple varieties on the list the nursury guy gave me using pomiferous as reference for most, lol.
I would like to think there is some kind of accuracy to it. Cross referencing their descriptions with other sites, when there is more than one source available, it did seem generally accurate if perhaps conservative for keeping times which is all the better as when they say an apple stores a long time that must mean it stores a really long time!
I emailed them to ask, I’ll let you know what they say. I wonder if they are early, early mid, mid, mid late, late, and then the last 2 are for ones that hang for the winter and through frosts.
It could be harvesting traditions as well. With Summer cookers the family traditionally harvests them all at once. Then after washed and what not; re-appear again another day to process them. They just do not get a chance to store long.