About the Produce Seasonality Finder
Every “what’s in season” chart you have seen is national, and a national chart is wrong for almost everyone. Sweet corn is ready about seventy days after the last spring frost — which is early July in Iowa and late May in Georgia. Asparagus and rhubarb start before the last frost; parsnips and Brussels sprouts are not worth eating until after the first fall frost, because the cold converts their starch to sugar.
So this tool does not use a calendar. It looks up your local frost dates and growing-season length from thirty years of station records, then shifts every crop’s harvest window to match. Warm-season crops are anchored to the last spring frost, cold-sweetened crops to the first fall frost, and citrus and tropical fruit are left on fixed windows because they are imported and your weather is irrelevant to them.
The second thing it does is tell you the truth about frozen. Out-of-season fresh produce is picked underripe and shipped for days; produce grown for freezing is picked ripe and blanched within hours. For peas, sweet corn, spinach and blueberries, frozen genuinely beats out-of-season fresh. For tomatoes and lettuce it does not, and the tool says so rather than pretending every vegetable is equal. Harvest windows are a bundled reference calibrated to your frost dates — a strong guide, not a substitute for what your actual farmers’ market has on the table this week.
Coming into peak within six weeks. If a recipe can wait, it is worth waiting.
Produce grown for freezing is picked ripe and blanched within hours; out-of-season fresh is picked underripe and shipped for days. For some crops that makes frozen the better buy.
Solid blocks are peak weeks; lighter blocks are in season. The red outline marks the current month. Every window is shifted to your own frost dates.
The best week to buy in bulk for preserving is the middle of the peak window, when quality is highest and price lowest. Dates are for your location.
How to Use the Produce Seasonality Finder
Check the location is right — everything below is computed from it — then read the peak list first. That is the short list worth acting on, because peak means a crop is being harvested locally at full ripeness right now, which is when it tastes best and usually costs least. The in-season list is broader and includes things that are available but past or before their best. The waiting list is the one that changes how you shop: if strawberries hit peak in three weeks, the ones in the shop today are not the ones you want.
Why Frost Dates, Not the Calendar
Crops do not follow months; they follow temperature. The two dates that organise the whole growing year are the last spring frost and the first fall frost, and almost every harvest window can be pinned to one of them:
- Warm-season crops — tomatoes, sweet corn, peppers, melons, beans — cannot go in the ground until after the last frost, and die at the first one. Sweet corn arrives roughly 70 days after last frost, tomatoes around 75, peppers nearer 80.
- Cool-season spring crops — asparagus, rhubarb, peas, spinach, radishes — run before and through the last frost and finish when summer heat makes them bolt. Their windows are short and easy to miss entirely.
- Frost-sweetened fall crops — parsnips, Brussels sprouts, kale, collards — are genuinely better after the first hard frost. The plant converts stored starch to sugar as an antifreeze, and you can taste it. Buying these in September is a mistake.
- Tree fruit is driven more by accumulated summer heat and the previous winter’s chill hours, so it tracks the length of the season rather than either frost date precisely.
That last-frost date differs by about three months across the continental United States. Any single chart is therefore wrong for nearly everyone who reads it, which is the whole reason this tool exists.
When Frozen Genuinely Beats Fresh
This is the least intuitive part of eating seasonally. Produce grown for freezing is bred for it, picked at full ripeness, and blanched and frozen within a few hours of harvest, which locks in both flavour and most nutrients. Out-of-season “fresh” produce is picked deliberately underripe so it survives days of shipping, and it never develops the sugars it would have on the plant. For peas, sweet corn, spinach, green beans, blueberries and cherries, frozen in February is straightforwardly better than fresh in February.
The exception is texture. Freezing forms ice crystals that rupture cell walls, so anything whose appeal is its crispness collapses: lettuce, cucumbers, radishes, celery. Tomatoes are the special case worth knowing — frozen tomatoes are poor, but canned tomatoes are excellent, because they are canned at peak ripeness and destined for cooking anyway. A good tin of tomatoes beats a February hothouse tomato in every sauce you will ever make.
Storing What You Bought
Two rules cover most losses. First, ethylene: apples, bananas, pears, avocados and stone fruit all emit it as they ripen, and it accelerates ripening and yellowing in anything sensitive stored nearby — leafy greens, broccoli, cucumbers. Keep them apart. Second, chilling injury: several things are damaged rather than preserved by the fridge. Tomatoes lose flavour compounds below about 55 °F and go mealy. Potatoes convert starch to sugar and brown badly when cooked. Onions and garlic sprout and soften. Basil blackens within a day. Winter squash keeps for months at room temperature and rots in the cold.
Buying at Peak Is Also the Cheap Option
Seasonal eating is often framed as a virtue that costs money, and for produce it is precisely the opposite. A crop at peak is being harvested locally in volume, which means minimal transport, no storage, and abundant supply — the conditions that produce the lowest price of the year for that item. The same crop out of season has been flown or trucked from another hemisphere and priced accordingly. If you plan the week around what is at peak rather than deciding the menu first, you generally spend less and eat better. This is also the moment to buy in bulk for preserving: the middle of the peak window is when quality is highest and price lowest, which is exactly when you want to be freezing, canning or making jam.
Pair this with the Produce Storage Guide for keeping what you bought, or the Frost Date Planting Planner if you want to grow some of it yourself — it uses the same underlying frost data. More in Cooking & Kitchen tools.
Frequently Asked Questions
Why does seasonality vary so much by location?
Because harvest timing is set by frost, not by the calendar. Sweet corn is ready roughly seventy days after the last spring frost, and that date differs by nearly three months between southern Texas and northern Minnesota. A single national seasonality chart is therefore wrong for almost everyone. This tool anchors each crop to your own local frost dates instead.
Is frozen produce as good as fresh?
For some crops it is genuinely better. Produce destined for freezing is picked at ripeness and blanched and frozen within hours, while out-of-season fresh produce is picked underripe and shipped for days. Peas, sweet corn, spinach, blueberries and green beans all freeze superbly. Tomatoes, lettuce, cucumbers and radishes do not, because freezing ruptures cell walls and they depend on crisp texture.
What does peak season actually mean?
It is the window when a crop is harvested locally in volume at full ripeness, which is when flavour and sugar content are highest and price is usually lowest. A crop can be available for months but at peak for only a few weeks. Buying at peak is the single biggest improvement most people can make to how their food tastes, and it costs less rather than more.
Do frost dates really affect fruit trees the same way?
Not identically. Tree fruit timing is driven more by accumulated heat over the summer and by chill hours the previous winter than by the last spring frost itself. A late spring frost matters enormously but as a risk to the blossom, not as a start date. The windows here shift with the local season length, which captures most of the regional variation, but tree fruit varies more by cultivar than vegetables do.
How should I store produce to keep it at its best?
The main rules are to keep ethylene producers away from ethylene-sensitive items, and not to refrigerate things that suffer chilling injury. Apples, bananas and stone fruit release ethylene and will over-ripen leafy greens and broccoli stored beside them. Tomatoes, potatoes, onions, garlic, basil and winter squash should all stay out of the fridge, where cold destroys texture and flavour or triggers sprouting.
