7 Vegetables You Can Still Plant in July (Zone 3 Garden Guide)

Summer is well underway, and with it all the amazing July weather we look forward to all year here in our Zone 3 region of Alberta, Canada. One of my favourite summer activities is vegetable gardening — something I look forward to throughout the winter months. To ensure a successful harvest in Zone 3, it’s essential to plant early, sometimes even starting seedlings indoors well before the soil thaws. But even with the best intentions, sometimes life gets away from us and planting gets sidelined. If this has happened to you and you’re wondering if there’s still time to plant and get a decent harvest, I’ve got good news for you—it’s not too late! Let’s look specifically at 7 vegetables you can still plant in July.

1. Lettuce

Because lettuce grows so quickly, it’s the perfect crop to plant later in the season in Zone 3. In fact, waiting to plant can actually result in a better harvest due to lettuce’s tendency to bolt in hot weather. Sowing seeds later in July means lettuce will be maturing in late August to September when weather is typically cooler. Cooler temperatures are best to prevent lettuce from going to seed prematurely.

• Best time to plant: mid-July through early August.
• If you’re planting in early July during a hot spell, choose a location that receives afternoon shade or use shade cloth to help keep the soil cool. Sow a few seeds every 1–2 weeks for a continual harvest.

Days to Maturity

• Baby leaf lettuce: 25–35 days
• Loose-leaf varieties: 40–50 days
• Romaine: 55–70 days
• Butterhead: 50–65 days

It’s best to choose loose-leaf varieties if planting later in July, as they are ready to harvest sooner.

Frost Tolerance

Lettuce is one of those vegetables that is quite frost-tolerant.

• Seedlings can handle light frosts.
• Mature plants typically tolerate temperatures down to about -2°C to -4°C (28–25°F) for short periods.
• Light frost often improves the flavour, making the leaves sweeter and less bitter.

Tips for Success

• Keep the soil moist. Lettuce seeds need moisture to germinate, and hot July weather can dry the soil quickly.
• Provide afternoon shade if temperatures are consistently above 27°C (80°F) to reduce bolting and heat stress.
• Mulch lightly after seedlings emerge to help retain moisture and keep the soil cooler.
• Succession sow every 1–2 weeks for a steady supply instead of one large harvest.
• Fertilize lightly. Mixing compost into the soil before planting can encourage healthy growth.

2. Radishes

Radishes are one of the quickest and easiest vegetables to grow. They like cooler late-summer temperatures and develop a sweeter flavour than radishes grown in the spring.

When to Plant

• Mid-July to late August in zone 3.
• Sow seeds every week until 4 weeks before your average first frost.
  

Days to Maturity

Some varieties are ready to harvest sooner:

• Cherry Belle: 22–28 days
• French Breakfast: 25–30 days
• White Icicle: 25–30 days
• Easter Egg Mix: 25–35 days

Frost Tolerance

Radishes are the perfect late-season crop in Zone 3 because they are so frost-tolerant.

• Seedlings can handle light frosts.
• Mature plants usually tolerate temperatures down to -3°C to -4°C (26–25°F).
• Cool autumn weather often produces the crispest, sweetest roots.

Tips for Success

• Plant in full sun for the best root development. Ensure afternoon sun during hot weather.
• Keep the soil evenly moist. Watering inconsistently may result in split or spongy roots.
• Sow seeds directly in the garden. Radishes don’t transplant well.
• Thin seedlings to about 2–5 cm (1–2 inches) apart once they’ve emerged. Crowding results in small or misshapen roots.
• Grow in loose, stone-free soil so the roots can expand easily.
• Avoid excess nitrogen fertilizer, which encourages leafy tops instead of plump roots.
• Harvest promptly. Leaving radishes in the ground too long can make them woody or hollow.

3. Spinach

Spinach is one of the best crops to plant in late July because warm soil temperatures speed germination, while cooler late-summer weather provides ideal conditions for plant growth. It will bolt (go to seed) in very warm weather, so keep this in mind when you’re deciding when to plant.

When to Plant

• Best time: Mid-July through early August in Zone 3.
• If daytime temperatures are consistently above 27°C (80°F), wait until late July when the weather begins to cool.
• Sow small amounts every 2–3 weeks for a continuous harvest into the fall.

Days to Maturity

Depending on the variety:

• Baby spinach: 20–30 days
• Full-size leaves: 35–50 days

Fast-growing varieties are best for July planting because they’ll have plenty of time to mature before frost.

Frost Tolerance

Spinach is one of the most frost-tolerant vegetables that can be grown:

• Seeds germinate in cool soil.
• Seedlings tolerate light frosts well.
• Mature plants can withstand temperatures as low as -6°C to -9°C (20–15°F).
• The flavour becomes sweeter after a light frost.

Tips for Success

• Plant in partial shade. Afternoon shade helps during hot July weather.
• Keep the soil consistently moist. Dry soil and heat increase the chance of bolting.
• Sow seeds directly into the garden, as spinach doesn’t transplant well.
• Plant seeds about 1–1.5 cm (½ inch) deep and thin seedlings to 7–10 cm (3–4 inches) apart.
• Add compost before planting to give the nitrogen spinach needs for leafy growth.
• Mulch lightly after seedlings emerge to help keep the soil cool and conserve moisture.

4. Green Onions

Another incredibly easy herb to grow is green onion. Unlike bulb onions, which require a longer growing season to form large bulbs, green onion matures quickly, making it an excellent choice for planting in July in Zone 3.

When to Plant

• Best time: Early July through early August in Zone 3.
• Sow seeds every 2–3 weeks for a continuous harvest until about 6–8 weeks before your average first fall frost.
• They grow best as temperatures begin to cool toward the end of summer.

Days to Maturity

Depends on the variety:

• Baby scallions: 30–40 days
• Full-size green onions: 50–70 days

Frost Tolerance

Green onions are very cold hardy.

• Seedlings tolerate light frosts.
• Mature plants can withstand temperatures of -6°C to -7°C (20–19°F) and often continue growing during cool autumn weather.
• With a row cover, they can sometimes be harvested even after light snowfall.

Tips for Success

• Plant in full sun, although they will tolerate partial shade.
• Mix compost into the soil before planting to encourage steady, healthy growth.
• Keep the bed weed-free, as young onions don’t compete well with weeds.

5. Beets

Beets thrive in cool weather, which means that as summer approaches fall, beets continue to develop. And the sweet root is not the only part of this vegetable that can be enjoyed—the leaves are also highly nutritious and excellent prepared in a variety of ways.

When to Plant

• Best time: Early to mid-July in Zone 3.
• For a fall harvest, sow seeds about 8–10 weeks before your average first fall frost.
• Beets germinate best when soil temperatures are between 10–24°C (50–75°F), making July an excellent time to start a late-season crop.

Days to Maturity

Depending on the variety:

• Baby beets: 35–45 days
• Full-size beets: 50–70 days

Fast-growing varieties are a great choice for July planting to ensure a harvest before hard frosts arrive.

Best Varieties for July Planting in Zone 3

• Detroit Dark Red – A reliable heirloom with deep red, sweet roots.
• Early Wonder – Produces both excellent roots and abundant greens.
• Red Ace – Fast-maturing with uniform, tender roots.
• Chioggia – An Italian heirloom with striking pink-and-white rings inside.
• Golden Boy or Boldor – Golden-fleshed beets with a mild, less earthy flavour that won’t stain your hands.

Tips for Success

• Plant in full sun with light afternoon shade in very hot weather.
• Sow seeds directly into loose, well-drained soil. Thin plants to 7–10 cm (3–4 inches) apart once they’ve sprouted.
• Mix compost into the soil before planting, but avoid excessive nitrogen fertilizer, which encourages leafy tops instead of large roots.

6. Baby Carrots

Baby carrots are an ideal vegetable to plant late season because they mature quickly and develop the best flavour in cool autumn weather. Not to be confused with the “baby carrots” sold in grocery stores, which are cut from full-grown carrots, baby carrots are harvested while still young, making them especially sweet and crisp.

When to Plant

• Best time: Early to mid-July in Zone 3.
• Sow seeds about 10–12 weeks before your average first fall frost.
• Choose fast-growing or short-rooted varieties if planting later in July.

Days to Maturity

Varieties differ, but a general guide:

• Baby carrots: 45–60 days
• Full-size carrots: 60–80 days

You can harvest as soon as the roots are the diameter of a finger, even if they haven’t fully grown.

Frost Tolerance

Carrots are one of the more frost-tolerant root vegetables.

• Mature carrots can handle temperatures down to about -6°C to -8°C (21–18°F).
• Light frost actually makes them even sweeter.

Tips for Success

• Plant in full sun for the best root development.
• Plant in loose, stone-free soil. Rocks and compacted soil can cause carrots to fork or become misshapen.
• Sow seeds directly about 6 mm (¼ inch) deep. Carrots don’t transplant well.
• Keep the seedbed moist. Carrot seeds are slow to germinate and can take 10–21 days, especially in warm weather. Don’t let the soil dry out during this time.
• Thin seedlings to about 2.5–5 cm (1–2 inches) apart once they’re a few centimetres tall. Proper spacing encourages straight, well-sized roots.
• Avoid too much nitrogen fertilizer, which can cause too much leafy growth and forked roots.

Best Varieties for July Planting in Zone 3

• Little Finger – Produces sweet, slim roots in about 55 days.
• Thumbelina – Small, round carrots that grow well even in heavier soils.
• Nelson – Fast-growing with exceptionally sweet flavour.
• Nantes Half Long – A classic variety with crisp, tender roots that’s well suited to shorter growing seasons.
• Mokum – A popular early variety known for its sweetness and smooth, uniform roots.

Gai Lan (Chinese Broccoli)

Gai lan is one of my new favourite vegetables to grow. It matures quickly, grows well as summer temperatures begin to cool, and tolerates light frost, making it a great choice for late summer planting. The leaves, stems, and flower buds are all delicious. Try them in salads, stir-frys or sautéed.

When to Plant

• Best time: Mid-July through early August in Zone 3.
• Plant seeds about 8–10 weeks before your average first fall frost.
• Avoid planting during the hottest part of summer, as excessive heat can cause plants to bolt and become bitter.

Days to Maturity

Depending on the variety:

• Baby leaves: 25–35 days
• Full-size plants: 45–60 days

Frost Tolerance

Gai lan is quite cold hardy.

• Seedlings tolerate light frosts.
• Mature plants can withstand temperatures down to about -4°C (25°F).
• Cool autumn weather produces sweeter, more tender stems and leaves.

Tips for Success

• Plant in full sun with afternoon shade during hot weather.
• Space plants 15–20 cm (6–8 inches) apart to allow sturdy stems to develop.
• Keep the soil consistently moist. Uneven watering can make stems tough and increase bitterness.
• Add compost to the soil before planting. Gai lan is a heavy feeder and likes nutrient-rich soil.
• Watch for cabbage worms and flea beetles, which commonly feed on members of the cabbage family. Row covers can protect plants while they are young.

Final Thoughts

Whether life got busy and you’re just getting started, you have empty spaces in your garden after harvesting early crops, or you simply want to extend your growing season, July and early August still give you enough time to plant fast-maturing vegetables. With a little planning, you can enjoy fresh, homegrown vegetables right up until frost. There’s nothing like stepping out to the garden to harvest fresh vegetables you’ve grown yourself and enjoying them at your table. Happy planting!

Looking for more gardening tips? Check out the Organic Gardening page!