Peak Season, Peak Nutrients: A Guide to Enjoying Late Summer Produce

There is a short but sweet window each year when nearly everything ripens at once, and late July is right in the middle of it. Sweet corn arrives, field tomatoes finally taste the way they are supposed to, local peaches fill the crates, and the beans keep coming faster than most gardens can keep up with.

This is also the stretch when local produce is at its nutritional best, since vitamin content is highest close to harvest and declines gradually through storage and transport. Here is a look at what's ready right now, what is inside it, and how to enjoy the abundance while it lasts.

What is at its peak right now

Across much of Canada, late July and early August bring:

• Sweet corn, at its sugariest within a day or two of picking
• Field tomatoes, including heirloom varieties that rarely travel far
• Peaches, nectarines, and early plums 
• Blueberries, raspberries, and the last of the summer strawberries
• Zucchini, patty pan squash, and cucumbers
• Green and yellow beans
• New potatoes with skins thin enough to leave on
• Fresh garlic, cured and ready to keep for months
• Basil, dill, and mint growing faster than most kitchens can use

Supply peaks now, which usually means prices settle into their friendliest range of the year. It is a good moment to buy generously.

Looking for more vitamin C? Berries, peppers, and potatoes deliver

Vitamin C is water soluble, so the body holds very little of it in reserve and appreciates a steady daily supply. Health Canada sets the recommended intake at 75 mg a day for adult women and 90 mg for adult men. Late summer produce makes those numbers easy to reach:

• Sweet red peppers, 1 cup chopped: roughly 190 mg, the highest concentration among common garden vegetables and about triple an orange by weight
• Strawberries, 1 cup halved: roughly 90 mg, which is more vitamin C per gram than an orange
• Raspberries, 1 cup: roughly 32 mg
• New potatoes with the skin on, 1 medium: roughly 25 mg
• Zucchini, 1 cup sliced: roughly 20 mg
• Field tomato, 1 medium: roughly 17 mg

Vitamin C is a factor in the development and maintenance of bones, cartilage, teeth, and gums, and it helps the body absorb iron from plant foods. It is sensitive to heat and dissolves readily in water, so raw preparations, quick steaming, and short stir fries hold on to the most.

Want to raise your vitamin K? Green beans, basil, and don't forget cucumber peel

Adults need about 90 mcg of vitamin K a day (women) and 120 mcg (men). Vitamin K plays a role in normal blood clotting and in bone metabolism, and because it is fat soluble, a splash of olive oil alongside improves how much you absorb.

• Beet greens, Swiss chard, and broccoli, 1 cup cooked: well over 100 mcg, with beet greens and chard supplying several times a full day's intake in a single serving
• Green and yellow beans, 1 cup cooked: roughly 60 mcg, close to half a day's intake
• Blueberries, 1 cup: roughly 29 mcg
• Fresh basil, 1/4 cup chopped: roughly 25 mcg
• Cucumber with the peel, 1 cup sliced: roughly 17 mcg

One helpful note: anyone taking anticoagulant medication is generally advised to keep vitamin K intake steady from day to day, so a quick conversation with your pharmacist or physician is worthwhile before a big change in leafy green habits.

Folate, potassium, and fibre round out the basket

Folate aids in red blood cell formation and receives particular attention during pregnancy. Sweet corn offers about 34 mcg per ear, cooked green beans about 40 mcg per cup, and beet greens considerably more. The adult recommendation sits at 400 mcg daily.

Potassium is an electrolyte the body uses to maintain fluid balance and support normal muscle and nerve function. Most Canadians land below the adequate intake of 2,600 mg for women and 3,400 mg for men, and summer produce helps: a medium new potato with the skin carries about 700 mg, a cup of sliced zucchini about 325 mg, a medium tomato about 290 mg, and a peach about 285 mg.

Fibre contributes to digestive regularity, with adequate intakes of 25 g daily for women and 38 g for men. Raspberries lead the summer field at roughly 8 g per cup, which places them among the highest-fibre fruits available anywhere. A potato with its skin brings about 4 g, a cup of green beans about 3 g, and an ear of corn about 2 g.

Colour is a useful clue

The pigments that make late summer produce so photogenic are compounds in their own right.

• Lycopene gives tomatoes their red colour. Heat and a little fat both improve how well the body absorbs it, which makes a slow-roasted tray of tomatoes one of the best uses for a bushel.
• Lutein and zeaxanthin appear in sweet corn, and both concentrate in the macula of the eye.
• Beta carotene shows up in peaches, dark leafy greens, and orange vegetables. The body converts it to vitamin A, which aids in the development and maintenance of night vision and helps maintain healthy skin.
• Anthocyanins create the deep blue and red of blueberries and raspberries, and they remain among the most actively studied compounds in nutrition research.

A few facts worth passing along

1. Sweet corn begins converting its sugars to starch the moment it leaves the stalk, which is why same-day corn tastes noticeably sweeter. Refrigerating it in the husk slows the process considerably.
2. Cooking concentrates the lycopene in tomatoes and makes it easier to absorb, so a jar of roasted tomato sauce delivers more per spoonful than the raw fruit.
3. Most of a cucumber's vitamin K sits in the peel, so leaving the skin on adds a genuine nutritional bonus.
4. Potatoes are a quietly significant source of vitamin C in the Canadian diet, largely because of how often and how generously they appear on the plate.
5. Vitamin C content in fresh produce begins declining after harvest, which gives food from a nearby farm a real head start over food that has spent a week in transit.

Small habits that help your body get more from the same plate

• Add a little fat to meals featuring vitamins A, E, and K. A vinaigrette on a salad or olive oil on roasted beans measurably improves absorption.
• Keep the skins on where practical. Potatoes, cucumbers, and peaches carry fibre and nutrients in and just beneath the peel.
• Choose quick cooking methods for vitamin C rich foods, and keep the cooking liquid for soups and sauces when you can.
• Pair vitamin C with plant sources of iron. Tomatoes with lentils, or strawberries alongside a spinach salad, help the body take up more of the iron on the plate.
• Eat produce within a few days of picking whenever possible, since that is when nutrient levels are at their highest.

Why local feels especially worthwhile this month

Produce grown nearby spends very little time in transit, which gives growers the freedom to choose varieties for flavour and texture. A tomato picked yesterday an hour down the highway is a different experience from one bred to survive a long journey.

There are quieter benefits too. Shorter distances mean less fuel burned and less packaging used along the way. Money spent at a local market circulates through the regional economy. And steady demand helps keep our Canadian farmland in production.

Shopping the market well

Go early for selection, later for volume. The best heirloom tomatoes tend to disappear in the first hour. Toward closing time, growers are often happy to move flats and bushels at a friendly price.

Ask what was picked this morning. Most growers enjoy the question, and the answer often points you toward something you had not planned to buy.

Bring your own bags and containers. Cloth bags for produce, a rigid container for berries and tomatoes, and a cooler bag in the car for the drive home. Delicate fruit arrives in much better shape when it travels flat and cool.

Buy in quantity when the price drops. A bushel of tomatoes or a flat of peaches is a bargain in late summer, and the next sections cover what to do with all of it.

Keeping everything fresh

A little care at home stretches the life of a market haul considerably, and it protects nutrient content along the way.

• Tomatoes: counter, stem side down, away from direct sun. Cool temperatures dull their flavour and soften their texture.
• Berries: refrigerate unwashed in a shallow single layer, then rinse just before eating.
• Corn: keep the husks on and refrigerate right away.
• Stone fruit: ripen on the counter until fragrant and slightly yielding, then move to the fridge for a few extra days.
• Herbs: trim the stems and stand them in a jar of water on the counter, like a bouquet.
• Cucumbers and zucchini: the crisper drawer, loosely covered, for about a week.
• New potatoes and garlic: somewhere cool, dark, and dry, with good airflow.

Five low-effort ways to save the surplus

None of these call for special equipment or a full canning setup.

1. Freeze berries on a tray. Spread them in a single layer on a parchment-lined sheet, freeze until solid, then transfer to a bag. They stay loose, so you can scoop out exactly what you need in February. Freezing preserves most vitamin and fibre content, which makes it one of the friendliest methods available.

2. Roast and freeze tomatoes. Halve them, toss with olive oil and salt, and roast slowly at 150°C until they collapse and concentrate. Freeze in flat bags.

3. Blanch and freeze beans. Two minutes in boiling water, then straight into ice water, dry well, and bag. The short blanch protects colour and texture through months of storage.

4. Make herb cubes. Blend basil, dill, or mint with olive oil, pour into ice cube trays, and freeze. Drop one into a pan in the middle of winter and the whole kitchen smells like July.

5. Try quick pickles. Cucumbers, beans, or thinly sliced zucchini in a jar with hot brine (equal parts vinegar and water, a spoonful of salt, a spoonful of sugar, plus garlic and dill). They are ready overnight and keep in the fridge for weeks.

Small habits that keep waste down

Canadian households discard a meaningful share of the food they buy, and summer produce moves quickly. A few routines help:

• Use the whole vegetable. Corn cobs make a lovely stock after the kernels come off. Beet greens sauté like chard and carry impressive vitamin K. Broccoli stems, peeled and sliced, are sweet and crunchy. Herb stems belong in the stock bag.
• Shop your fridge first. A quick look before market day keeps you from buying a third bunch of dill.
• Keep a "use soon" shelf. One designated spot at eye level for anything on its last few days.
• Compost what is left. Municipal green bin programs across the Hamilton and Halton region accept produce scraps, and a backyard bin turns them into something useful for next year's garden.

Enjoy the abundance while it is here

Late summer rewards a little planning. An afternoon spent freezing berries or roasting a tray of tomatoes pays you back months later, on an evening when cooking from scratch feels like more than you have in you.

Nutrient values above are typical averages and will vary with variety, growing conditions, and preparation. For guidance tailored to your own situation, a registered dietitian, pharmacist, or physician is the best place to start.

We would love to hear what you are making with this season's haul. Share your favourite way to put up summer produce, and happy market season from all of us at Healthtree.