Seasonal produce wins on taste and price, while its climate edge depends on heating

Key takeaways

• Vitamin C starts breaking down at harvest; in studies compiled by University of California, Davis, scientists, spinach lost about three quarters of it in one to three weeks of cold storage and all of it within a week at room temperature³.
• Cold can change a crop from the inside: in a Japanese study, spinach that went through freezing temperatures before harvest reached about 175 milligrams of vitamin C per 100 grams, versus 50 to 70 in milder weather⁴.
• A 2017 study of 398 tomato varieties found 13 flavor chemicals at lower levels in modern types, which breeders had chosen mainly for yield, disease resistance and firmness⁷.
• USDA economists who tracked prices paid to growers from 1980 to 2012 found that strawberry, peach and grape prices rise and fall with the harvest, while prices for apples and oranges, which keep well, barely change⁸.
• Tomatoes from heated Austrian greenhouses carried nearly twice the greenhouse gas emissions of tomatoes shipped from Spain, and unheated tomatoes grown in their natural season carried the least¹.

Picture two tomatoes on a store shelf in Vienna, Austria. One grew nearby in a heated greenhouse. The other made the long trip from Spain.

Which one is easier on the climate? Austrian researchers worked it out in a study published in 2014. Each kilogram of the heated local tomatoes carried about 1,397 grams of greenhouse gases by the time it reached the store, the most of any supply chain they measured¹. The Spanish tomatoes carried 759 grams¹.

The clear winner was a third tomato. It was organic and grown in Austria in unheated plastic tunnels during its natural season, and it carried just 180 grams¹.

The lesson: the calendar can matter more than the map. Food grown in its own season tends to need less help from heaters and storage. The same timing often brings better flavor and lower prices, and this guide ends with a calendar and a weekly plan to help you catch it.

Vitamin C starts slipping the day a vegetable is picked

Vitamin C is one of the most fragile nutrients in produce. The NIH Office of Dietary Supplements notes that heat destroys it and that long storage and cooking lower the amount in food². Adult women need 75 milligrams a day and men need 90. Those are the National Academies’ 2000 recommended amounts, listed in the ODS fact sheet updated in 2025².

In 2007, food scientists at the University of California, Davis, reviewed decades of research on fresh, frozen and canned produce³. They wrote that vitamin C begins to break down right after harvest³. In the studies they compiled, spinach kept cold lost about three quarters of its vitamin C over one to three weeks. Spinach left at room temperature lost all of it within a week³.

Peas were faster still. A 1935 study cited in the review found that green peas lost about half their vitamin C in the first one to two days after picking³. Broccoli held up better in the fridge, with no loss after a week in one study and losses of 13% to 48% after three weeks in another, depending on the year³.

So fresh wins on vitamin C, the reviewers concluded, but only when it reaches your plate quickly³. Every day in a truck, a warehouse or your crisper drawer chips away at that lead. By the time store-bought fresh produce is eaten, frozen or canned versions may hold about as much³. Our guide to processed foods covers a newer study of frozen produce.

That is the core nutrient case for seasonal produce. Food harvested at its peak and eaten within days has had less time to lose what it started with.

Cold weather can make spinach sweeter and richer

Season also shapes what builds up inside a plant while it grows.

A Japanese horticulture study published in 2004 tracked spinach and komatsuna, a leafy green, grown in winter⁴. When daily lows in the 10 days before harvest stayed above about 41 degrees Fahrenheit (5 degrees Celsius), vitamin C stayed around 50 to 70 milligrams per 100 grams⁴. As the lows fell toward 23 degrees (minus 5 Celsius), vitamin C climbed to about 175 milligrams, and sugar rose about fivefold⁴.

If you’ve heard that cold weather sweetens winter greens, this study offers support, at least for these two greens.

Still, “in season” doesn’t always mean “more of everything.” A team led by Luke Howard at the University of Arkansas grew 26 types of spinach in spring and in fall⁵. The spring crop had about 88% more phenolic compounds, a family of plant antioxidants, than the fall crop⁵. The researchers credited the tougher spring conditions: more heat, stronger light and more disease⁵.

The UC Davis reviewers made the same broader point: nutrient levels shift with variety, growing location, ripeness, season and handling³. Seasonal eating tilts the odds toward fresher food. It doesn’t promise a nutrient bonus in every crop.

Many store tomatoes were bred to travel, not to taste

In 2017, an international team led by Harry Klee of the University of Florida published a study in the journal Science on why modern tomatoes lack flavor⁶⁷. The researchers analyzed 398 tomato varieties, from modern commercial types to heirlooms and wild relatives⁷. A consumer taste panel rated 160 samples⁷.

The team found 13 aroma chemicals tied to flavor at significantly lower levels in modern varieties⁷. For decades, breeders had focused on yield, disease resistance and firmness, the traits that help a tomato survive shipping and storage⁷. Klee said modern tomatoes had lost good versions of several flavor genes, and that for 50 years breeders lacked tools to screen for taste routinely⁶.

“We can make the supermarket tomato taste noticeably better,” Klee said in a University of Florida news release⁶. The team relied on classic breeding, not genetic engineering⁶.

Florida and California grow two-thirds to three-fourths of U.S. commercial fresh-market tomatoes⁶. For shoppers in most other states, a U.S.-grown store tomato faces a long trip, the very test modern varieties were bred to pass⁶⁷.

The lesson for shoppers is that variety matters as much as the calendar. In summer, ask market growers which varieties they grow, and taste a few. Out of season, plain canned tomatoes are a practical stand-in for cooking.

Prices drop at peak harvest, but only for some crops

Most shoppers notice berries getting cheaper in summer. USDA’s Economic Research Service (ERS) has put numbers on that pattern, first on the farm and then in the store.

The farm numbers come from a 2014 ERS report. Its economists followed what growers were paid for major fruits each month from 1980 to 2012⁸. That’s the farm price, not the price on your receipt⁸.

Three fruits moved with the harvest: strawberries, peaches and grapes⁸. Strawberries had the biggest swing. From 2010 to 2012, their costliest month on the ERS index ran about three times their cheapest⁸. Grower prices usually slid from January through April, sat low all summer and rose again in the last four months of the year⁸.

Peaches cost the most in May, when only about 10% of the year’s supply is on the market, and the least in July or August⁸. Grapes hit their low from July through September⁸.

Apples and oranges hardly budged⁸. Apples keep for months in storage, so packers can sell them evenly, and imports arrive when U.S. supplies run low. Oranges have a long harvest window that lets growers time their sales⁸.

ERS suggested that farm and store prices for fresh fruit probably move together, since the path from farm to shelf is short. But the report didn’t test that⁸.

For vegetables, ERS looked at store prices directly. Using food-at-home prices from 2016 to 2018, it found the biggest seasonal swings in starchy vegetables other than potatoes, mostly corn⁹. Dark green vegetables swung the least⁹. Shoppers noticed: spending on the starchy group peaked in summer, when prices were lowest⁹.

Both data sets are several years old. We did not find a newer ERS analysis of seasonal produce prices.

For your budget, timing pays off most with perishable crops that don’t store well, such as berries, peaches, grapes and sweet corn. With storage crops such as apples, potatoes and onions, the season matters less.

The climate math turns on heat, not miles

Back to those tomatoes in Vienna. The Austrian team traced most emissions to heating, packaging and transport, with heating offering the biggest chance for cuts¹. Wood-chip heat would halve the greenhouse tomatoes’ emissions, the team estimated. Even then, they would carry about four times the footprint of the best seasonal local ones¹.

A 2013 British study pointed the same way. Tomatoes and strawberries from Spain had a lower climate impact than British-grown ones, even after counting the trip¹⁰. But British potatoes and beef beat imports, so no single rule fits every food¹⁰. The authors added that chasing the lowest carbon number can shift the burden elsewhere, such as onto water supplies¹⁰.

The Austrian authors warned that promoting local food without checking its emissions could backfire for the climate¹. Their numbers point to a sharper rule of thumb: food grown in its natural season, without added heat, came out ahead¹.

Our upcoming article on local food looks at food miles in more depth, and a later article covers seasonal eating from the planet’s side.

Old healing traditions built calendars around food

Long before anyone measured carbon, healing traditions tied meals to the seasons.

Ayurveda, India’s traditional medicine, calls its seasonal routine ritucharya and treats it as a form of prevention¹¹¹². For the hot summer season, called Greeshma, classical texts favor sweet, light and cooling foods and plenty of liquids¹¹. Examples include rice, roasted barley flour with sugar, yogurt with sugar and pepper, fruit drinks and cool water, with less salty, sour and pungent food¹¹.

Some Ayurvedic researchers now propose that ritucharya works partly through the gut microbiome, the community of microbes in the digestive tract¹². That idea comes from a 2021 review and remains a hypothesis, not a tested result¹².

Traditional Chinese medicine counts dietary therapy among its practices, along with acupuncture, herbs, massage and tai chi¹³. It sees the human body as a small version of the surrounding universe¹³. The National Center for Complementary and Integrative Health says that for most conditions, there isn’t enough rigorous research to know whether TCM methods work¹³.

We found no clinical trials comparing a seasonal eating pattern with a year-round diet on health outcomes. Health claims for seasonal eating as such fall in the “not enough evidence” category.

For many readers, though, eating with the seasons isn’t mainly about nutrients. It’s a way to stay connected to the land, the weather and the people who grow food. That connection is worth keeping whether or not a trial ever measures it.

What the evidence supports

Claim	Rating	What the research shows
Produce loses vitamin C in storage after harvest	Strong evidence	Losses show up across decades of measurements; leafy greens and peas lose it fastest3
The growing season changes nutrient levels	Promising but early	Cold raised vitamin C in winter spinach, and spring stress raised spinach antioxidants; effects vary by crop45
Berries, peaches, grapes and sweet corn cost less at peak harvest	Strong evidence	Decades of USDA data show big seasonal price swings, measured at the farm for fruit and in stores for corn89
Storage crops such as apples get much cheaper in season	Evidence says no	Grower prices for apples and oranges barely move with the season8
Local produce always has a smaller climate footprint	Evidence says no	Local tomatoes had higher emissions than Spanish imports in two studies; in Austria, greenhouse heat was the main reason110
Eating seasonally, or following ritucharya, improves health	Not enough evidence	No trials found; reviews offer hypotheses only1112

A seasonal produce calendar and a weekly plan

USDA’s SNAP-Ed program publishes a national seasonal produce guide, a handy starting point¹⁵. But it lists bananas and plantains in all four seasons, and mangos and avocados in several¹⁵. Those are supermarket seasons, filled by imports. USDA itself notes that local seasons depend on growing conditions and weather¹⁵.

For local timing, check your state’s extension service, the public outreach arm of land-grant universities. Mississippi State University’s statewide list, for example, notes that southern counties harvest earliest¹⁴. Our calendar combines USDA’s national list with Mississippi’s months.

Season	Vegetables to look for	Fruits to look for	Mississippi timing example
Spring (March–May)	Asparagus, peas, spinach, lettuce, radishes, Swiss chard	Strawberries, rhubarb	Strawberries March–May; asparagus and English peas March–June
Summer (June–August)	Tomatoes, sweet corn, green beans, okra, cucumbers, summer squash, peppers, eggplant	Peaches, blueberries, blackberries, cherries, melons, plums	Tomatoes and okra June–October; peaches May–September; blueberries May–July
Fall (September–November)	Sweet potatoes, winter squash, pumpkin, broccoli, cauliflower, Brussels sprouts, kale	Apples, pears, grapes, cranberries, pomegranates	Sweet potatoes August–November; muscadine grapes September–October; pears August–November
Winter (December–February)	Cabbage, collards, kale, leeks, parsnips, turnips, rutabagas, winter squash	Oranges, grapefruit, kiwifruit, apples, pears	Cabbage, collards and turnips through December; pecans and persimmons through December

Sources: USDA SNAP-Ed Connection¹⁵ and Mississippi State University Extension¹⁴. Expect later dates the farther north you live, and check your own state’s list.

A weekly “shop the season” plan

1. Before you shop, check the calendar or your state’s list, and look for produce that’s piled high and priced low.
2. Pick two or three peak items and plan meals around them, rather than planning meals first.
3. Buy delicate produce for the next few days only. Eat leafy greens and peas first, since they lose vitamin C fastest³.
4. Lean on storage crops between harvests, such as apples, onions, potatoes, sweet potatoes, beets and garlic¹⁴.
5. When a favorite is cheap, buy extra and freeze it the same day, using the steps below.
6. Out of season, choose plain frozen or canned produce without added sugar or sauce.

Freeze the peak before it fades

Freezing is the easiest way to stretch a cheap harvest. The UC Davis review found that blanching, a quick dip in boiling water or steam, followed by freezing destroys less vitamin C than canning does³.

Frozen food isn’t frozen in time, though. Its vitamin C keeps slipping in the freezer and drops again when you cook³.

Canning works the other way around. The heat of the canner takes a big bite at the start, and after that the losses are small³. Once everything is cooked, frozen or canned vegetables sometimes hold as much vitamin C as cooked fresh ones, or more. It depends on the vegetable³.

How you cook matters too. ODS notes that steaming or microwaving may reduce the vitamin C lost in cooking².

Freeze produce the day you buy or pick it, follow tested blanching times from your extension service, and date every bag. Home canning needs tested recipes to be safe; our upcoming guide to food storage covers it.

Questions readers ask

The bottom line

Eating with the seasons is less about rules than about timing. Produce eaten soon after harvest keeps more of its vitamin C, peak-season fruit often costs less, and flavor depends on choosing the right variety as well as the right month.

The climate story is more complicated. In the Austrian study, the tomato grown in its natural season without added heat had the smallest footprint by far. Use the calendar, buy perishables at their peak, freeze extras, and let storage crops and plain frozen produce fill the gaps.

Related reading

• Frozen peas and candy bars are both processed, and the difference matters
• Most adults eat too few vegetables, and five a day can cost under $3
• What a farmers market sign promises, and what you should ask
• Humors, doshas and qi: what science kept from old healing philosophies
• A healthy month of groceries, priced by the government

Sources

1. Theurl MC, Haberl H, Erb K-H, et al. “Contrasted Greenhouse Gas Emissions From Local Versus Long-Range Tomato Production.” Agronomy for Sustainable Development, 2014. link.springer.com
2. NIH Office of Dietary Supplements. “Vitamin C: Fact Sheet for Health Professionals.” Updated July 2025. ods.od.nih.gov
3. Rickman JC, Barrett DM, Bruhn CM. “Nutritional Comparison of Fresh, Frozen and Canned Fruits and Vegetables. Part 1. Vitamins C and B and Phenolic Compounds.” Journal of the Science of Food and Agriculture, 2007. ucanr.edu
4. Tamura A. “Effect of Air Temperature on the Content of Sugar and Vitamin C of Spinach and Komatsuna.” Horticultural Research (Japan), 2004. jstage.jst.go.jp
5. American Chemical Society. “Spinach Shows Seasonal Variation in Antioxidant Content” (news release on Howard LR et al., Journal of Agricultural and Food Chemistry). Newswise, 2002. newswise.com
6. Buck B. “Team Discovers Key to Restoring Great Tomato Flavor.” University of Florida News, UF/IFAS, January 2017. archive.news.ufl.edu
7. Tieman D, et al. “A Chemical Genetic Roadmap to Improved Tomato Flavor.” Science, 2017. doi.org
8. Plattner K, Perez A, Thornsbury S. “Evolving U.S. Fruit Markets and Seasonal Grower Price Patterns.” USDA Economic Research Service, FTS-357-01, September 2014.
9. Byrne AT, Sweitzer M. “Starchy Fresh Vegetables (Excluding Potatoes) Had the Most Seasonal Price Variation From 2016–18.” USDA Economic Research Service, Charts of Note, May 2024. ers.usda.gov
10. Webb J, Williams AG, Hope E, Evans D, Moorhouse E. “Do Foods Imported Into the UK Have a Greater Environmental Impact Than the Same Foods Produced Within the UK?” International Journal of Life Cycle Assessment, 2013 (abstract via FAO AGRIS). agris.fao.org
11. Kumar K, Kacha Y, Vaghela DB. “Review on Role of Diet in Greeshma Ritu.” Innovare Journal of Ayurvedic Sciences, 2019. journals.innovareacademics.in
12. Deepthi R, Vandana Rani M, Robin DT, Dileep A. “Adopting Seasonal Regimen (Ritucharya) to Modulate the Seasonal Variation in Gut Microbiome.” Journal of Ethnic Foods, 2021 (abstract via Amrita Vishwa Vidyapeetham). amrita.edu
13. National Center for Complementary and Integrative Health. “Traditional Chinese Medicine: An Introduction.” NIH, updated October 2013. files.nccih.nih.gov
14. Wilson J, compiler. “Buy Fresh Fruits and Vegetables in Season!” Mississippi State University Extension, Publication P3144, revised 2024. extension.msstate.edu
15. USDA SNAP-Ed Connection. “Seasonal Produce Guide.” USDA Food and Nutrition Service.