late potatoes

as I have some seed potatoes leftover  I've been told if I plant them the first of July I would get late scrapers around September much the same as digging early potatoes now is that correct 

because I'm a bit reluctant to through the seed away

I would give them a chance. With the terribly wet weather we had in May a lot of people were late planting any potatoes outside i would definitely have a go rather than waste the seed if it works good enough in your area then happy days.