Delete 1,000 pumpkins by hand! Please note the seven pumpkins that qualify for this achievement: Fresh Pumpkin, Freshly Picked Pumpkin, Carving Pumpkin, Pumpkin on the Vine, Uncarved Pumpkin, Ready-to-Carve Pumpkin, and Carvable Pumpkin.

is it ever possible to get that many pumpkins?? i was trying to get them but i failed to get them.... will this achievement carry over to next year?

Yeah, you probably can't get them in 1 year of Morostide. You can buy them from user shops if you really want it, but it does carry over and you can work on it next year :)

you can also get pumpkins for the next day or two by fighting the first and fourth opponents in the Morostide events tab of the battle colosseum. Even a fairly new battle pet should be able to battle these guys pretty well...