Every fall we get the same two calls. Early September: "Can you do it this weekend?" Late October: "Is it too late to bother?" Both are fair questions, and the answer to both is the same piece of math, so here it is in full.
The equation
A sound, uncarved pumpkin on a shaded porch holds four to eight weeks in our climate (the full care math is here). Our installing season runs 6 September to 23 October, seven weeks, and it stops there on purpose: every porch we do is finished well before Halloween, and a display that goes up on the last day still has the whole of the month it was bought for. So the question is not whether to decorate, it is which week, and every week in that seven is a real trade.
Early September: the longest run
Going up in the first two weeks buys you the most days of pumpkins, and it is genuinely lovely: the light is turning, the crowds have gone, and you get to enjoy the porch through the whole of what is arguably the best month here. The honest caveat is heat. September afternoons on this coast still touch 80°F, and warmth is what ages fruit fastest, so an early install on a full-sun, west-facing step will show its age sooner than the same display in shade. If you want early and long, a covered or shaded porch does most of the work, and the thick-skinned heirlooms do the rest.
Late September to early October: the sweet spot
For most homes, the last week of September or the first days of October is the one to want. Cool nights from the start, which is what pumpkin longevity most wants, and full color through the whole of October: the month the porch actually gets seen, photographed and trick-or-treated. It is also the most requested pair of weeks by a distance, which is the practical reason to book it early rather than think about it.
Mid to late October: the freshest Halloween
An install in the last two weeks misses some of the season but lands in perfect keeping weather and looks its absolute best on the night itself. If it is the 15th and you are wavering: yes, it is still worth it, and the porch will look newer on Halloween than one put up six weeks earlier.
Why the booking happens earlier than the install
Here is the wrinkle from our side of the van: everyone independently does this math, gets the same answer, and wants the same two weeks. We install six porches a week and a week closes on the site once it is full, so the weeks around October 1st go first, and they go to whoever's deposit is in. That is the line, and there isn't another one. Booking holds your week the moment the deposit lands; the pumpkins themselves are bought fresh the week we install, so booking early never means older fruit. (How the deposit works is explained here.)
Frost, and the end of the season
First frost in southern Ocean County typically arrives late October to mid-November, and a light frost on whole, hard-shelled pumpkins is survivable; it is the hard, repeated freezes that end things. Pumpkins are farm produce and they weather, so how long any particular one holds is genuinely weather and luck. When a display finally goes, it goes to compost, or we come and take it away if you added end-of-season removal when you booked.