The best food on Long Island in September is not in a supermarket. It is on a folding table at the end of a driveway, in a barn doorway on Sound Avenue, at a stand that might be open today and might not, depending on the weather, the picking and whether the honor box needs refilling. Finding it has always been the hard part. A new app built on the North Fork is trying to fix exactly that, and half of the team that built it is 12 years old.

A mother, a son and a map

FarmScout is the work of Heather Spinelli of Cutchogue and her son Luca, who started building the prototype when he was 11. The idea is simple to describe and was clearly not simple to build: one map, searchable by what you want or what you want to do, that shows the farms, farm stands, farmers markets, vineyards, orchards, u-picks and agricultural events around you, sorted by distance.

The family lives in the middle of the densest farm country in New York State, and it shows in how the app thinks. You can search for a thing: tomatoes, honey, eggs, flowers, pumpkins, apples, and later in the year, Christmas trees. Or you can search for a day out: u-pick fields, tastings, tours, live music, farm dinners, festivals, even farm stays and glamping. Results open into listings with what the business offers, what is on for the season and how to reach the farm directly.

The timestamp is the smart part

Anyone who has driven 40 minutes to a farm stand that turned out to be closed knows the real problem with farm shopping: the information goes stale faster than the corn. Stands sell out. Fields close after rain. A u-pick that was open Saturday is picked out by Tuesday.

FarmScout's answer is to date-stamp its information. Listings carry an observed date or timestamp showing how recently they were updated, so you can tell the difference between a stand that reported fresh stock this morning and one nobody has checked on in a month. Farmers and sellers can submit their own updates, and the app also gathers from public sources through the day.

That one design decision is worth more than any glossy directory, because it is honest about the thing directories always hide: freshness of information, at a farm stand, is the whole product.

Born on the North Fork, now well past it

The app started as a local project and outgrew the zip code quickly. The catalog has passed 11,000 farm and farm-related listings nationwide, according to the family, which means it works as well for a Catskills weekend or a Vermont leaf-peeping drive as it does for a Saturday run down Route 25. The North Fork roots still show: this is an app designed by people who actually make the Sound Avenue circuit, not by a startup guessing at what a farm stand is.

For Long Islanders the timing could hardly be better. Apple picking is under way on the East End, pumpkin season opens within weeks, and the stretch from now through Thanksgiving is when the Island's farm stands, cideries and u-pick fields do the work they wait all year for.

What it costs and where to get it

FarmScout is on the iOS App Store now, listed as Farm Scout Local, and the download is free. The family has said full access stays free through September 15, after which the app costs $14.99 a year, which comes to about a dollar and a quarter a month. An Android version is in development, a decision the family has attributed to the volume of requests from Android users.

For farms, the pitch runs the other direction: growers, stands, nurseries and vineyards can claim a profile, keep their stock and hours current and post their events, which puts the smallest operations on the same map as the big destination farms.

What it means for your weekend

Long Island loses a little more farmland every year, and the farms that remain live on direct sales: the stand, the u-pick, the fall festival, the CSA box. Anything that moves a family from the supermarket to the stand on a Saturday is worth having, and a tool built by a Cutchogue kid who grew up around those stands is a fitting one. Download it before the pumpkins come in, and check the timestamp before you drive.