How to keep your jack-o’-lantern from turning into moldy, maggoty mush before Halloween : For many Americans, pumpkins mean that fall is here. In anticipation, coffee shops, restaurants and grocery stores start their pumpkin flavor promotions in late August, a month before autumn officially begins. And shoppers start buying fresh decorative winter produce, such as pumpkins and turban squash, in the hot, sultry days of late summer. But these fruits – yes, botanically, pumpkins and squash are fruits – don’t last forever. And they may not even make it to Halloween if you buy and carve them too early.