What to Plant in August in a Cold Climate Garden

In cold climate gardens across Canada, Scandinavia, northern Europe, and the northern United States, August marks the start of the late growing season. While some summer crops are finishing, this article will tell you what to plant in August. Many fast-growing and cold-tolerant vegetables can still be planted successfully.

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Soil temperatures in August are still warm from summer, and seeds germinate quickly. With the right crop choices, you can keep harvesting fresh vegetables well into October, even in regions with short summers.

August planting is one of the most underused strategies in cold climate gardens. It is also one of the most rewarding, an easy way to extend the harvest in short growing seasons.

If you are building a full seasonal plan, start with our cold climate planting calendar, which explains what to plant throughout the growing season.

Quick Answer: What to Plant in August in a Cold Climate

If you are gardening in a cold or short-season climate, these vegetables can still be planted successfully in August:

• spinach
• arugula
• lettuce
• radishes
• turnips
• green onions
• kale
• mustard greens

These crops grow quickly and tolerate cooler temperatures as autumn approaches.

Many are also covered in our guide to fast-growing vegetables for cold climates, which explains how some crops can be harvested in just a few weeks.

August Planting Checklist for Cold Climate Gardens

Use this checklist to prepare your garden for autumn harvests.

• Sow fast-growing greens such as spinach, arugula, and lettuce

• Plant radishes and turnips for late-season harvests

• Choose cold-tolerant crops that grow well in cooler temperatures

• Keep soil consistently moist during late summer heat

• Use raised beds or sunny garden spots to maintain warm soil

• Begin preparing simple season extension methods if needed

August planting focuses on crops that will mature as temperatures begin to cool.

Why August Planting Works in Northern Gardens

The most common mistake in cold climate gardening is stopping too early. August is not the end of the planting season, it is the beginning of the late-season harvest strategy that will carry your garden into autumn.

There are several reasons for this.

First, soil temperatures are usually at their warmest point of the year. Warm soil allows seeds to germinate quickly, even when air temperatures begin to cool.

Second, many vegetables actually prefer cooler temperatures. Crops such as spinach, lettuce, and kale often grow better in late summer and early autumn than during hot midsummer conditions.

Finally, the risk of heat stress is lower in northern regions. This allows cool-season vegetables to grow steadily without bolting too quickly.

Fast-Growing Vegetables to Plant in August

Fast-growing vegetables are the most reliable crops for late planting in cold climate gardens.

Radishes

Radishes remain one of the fastest vegetables you can grow.

They are ideal for August planting because:

• they mature quickly
• they tolerate cool temperatures
• they can be harvested within three to four weeks

Radishes can often be planted several times throughout late summer for continuous harvests.

For more fast crops, see our guide to fast-growing vegetables for cold climates.

Arugula

Arugula grows quickly and develops its best flavor in cooler weather.

Advantages of planting arugula in August include:

• rapid germination
• strong growth in cool temperatures
• repeated harvesting of young leaves

Arugula is one of the easiest leafy greens for succession planting.

More growing tips can be found in our guide to leafy greens for cold climate gardening.

Lettuce

Loose-leaf lettuce can still be planted successfully in August in many northern regions.

Because lettuce prefers cooler weather, late summer conditions often produce better results than hot midsummer temperatures.

Many varieties allow cut-and-come-again harvesting, meaning you can harvest outer leaves while the plant continues growing.

Cold-Tolerant Crops That Thrive in Late Summer

Some vegetables planted in August grow more slowly but tolerate colder conditions as autumn approaches.

Spinach

Spinach is one of the most reliable late-season crops in northern gardens.

Benefits of August planting include:

• strong cold tolerance
• excellent growth in cool weather
• potential harvests well into autumn

Spinach often performs better in late summer than during warm midsummer conditions.

Kale

Kale is extremely cold-hardy and often improves in flavor after exposure to frost.

Advantages of planting kale in August include:

• long harvest window
• excellent frost tolerance
• continued production into autumn

Kale is one of the most dependable vegetables in cold climate gardens.

More information can be found in our leafy greens guide.

Turnips

Turnips are another excellent crop for late summer planting.

They grow relatively quickly and tolerate cooler temperatures better than many other root vegetables.

Both the roots and the leafy greens can be harvested.

Tips for Successful August Planting

August planting rewards a slightly different approach than spring gardening. These strategies will help you get the most from the remaining season.

Choose quick-maturing crops

Vegetables with short maturity times perform best in late planting situations.

Keep soil moist

Late summer conditions can dry the soil quickly. Consistent moisture improves germination and growth.

Use succession planting

Instead of planting everything at once, sow small amounts every week or two. This allows you to harvest continuously as plants mature.

Protect crops as temperatures drop

As autumn approaches, simple protection methods can extend the growing season.

Garden fleece, row covers, cold frames and low tunnels help stabilize temperatures and protect crops from early frost.

You can learn more in our guide to season extension for cold climate gardening.

What Not to Plant in August in Cold Climates

By August, the window for long-season crops has closed. Some vegetables simply cannot mature before the first autumn frost, no matter how good the conditions are.

These include:

• tomatoes
• peppers
• pumpkins
• winter squash
• corn

These crops need more time and warmer temperatures to mature successfully.

Warm-season vegetables in northern gardens are usually started earlier in the year or indoors.

How August Planting Extends the Harvest

August planting is not a fallback, it is a deliberate strategy. In cold climate gardens, the late growing season can be just as productive as midsummer if you choose the right crops.

By planting fast-growing crops in August, you can continue harvesting fresh vegetables well into autumn. Many leafy greens and root crops actually perform better in cooler weather.

With the right crops in the ground now and simple frost protection ready for when autumn arrives, your garden can keep producing well into October.

If your berry harvest is still coming in, now is the time to process it. See: How to Preserve Berries from a Cold Climate Garden →

Continue Planning Your Garden

August sits at the turning point of the season. Use these guides to round out your planting plan:

• What to plant in April
• What to plant in May
• What to plant in June
• What to plant in July
• What to plant in September

You can also see our full cold climate planting calendar for a month-by-month overview of what to plant throughout the growing season.