Planting Cool Weather Vegetables: When and Why

I sometimes use affiliate links in content. This doesn’t cost you anything but I may make a commission payment from anything you buy through these links. As an Amazon Associate I earn from qualifying purchases. All opinions remain my own.

Cool weather vegetables are a must when you live in the UK or US. While it may be tempting to plant warm weather vegetables when there is a heatwave, these veggies will need too much water when the temperatures rise and they won’t last long.

Cool weather vegetables have natural protection from heat when planted when the ground is cold. In this blog post, we’ll take a look at when to plant cool weather vegetables for both the UK and the US as well as some popular types of cool weather veggies that you can add to your garden!

Why plant vegetables in the fall?

Although they do best in full sunshine, numerous vegetables don’t require a lot of heat. Spinach, lettuce, and radishes, to name a few, thrive in the warm days and chilly nights of early fall.

Finally, the soil in your garden is ideal for a fast sprout because it’s mild and warm, unlike spring when the ground is chilly. The soil in your garden, on the other hand, is nice and warm, making it perfect for a rapid spurt. Fall crops, on the other hand, may slow down as daytime temperatures fall.

Another benefit is that as the temperature drops, there are usually fewer insect pests. Insects that live in cold climates are going into dormancy. Fall crops will have fewer weeds to compete with for nutrients, in general.

You may save money on irrigation, too. While fall crops require moisture, as do many other plants during the summer, the soil does not dry out as rapidly in the intense heat of summer.

You’ll want to get back into the garden and take advantage of the cool weather, too. However, production may take longer in the fall than in the spring. Why? Although seeds germinate faster when planted in warm soil than they do at cool springs, declining air temperatures might slow growth.

The best time to plant cool-season vegetables

Always check seed packets or catalogues to see how long a certain cultivar takes to mature before harvesting. To determine when to plant for fall, take your average first frost date and subtract about that many days from it.

In USDA zone 5, for example, the first frost typically comes around mid-October. Radishes take about 21 days to mature. That means you may sow radish seeds in late September. But don’t be frightened to start a little later…you might end up with a fall that is longer than average and extra food. It’s worth taking the risk.

Average frost date in the UK

Here in the UK, it depends on what part of the country you live in as to when you are likely to see some frost. There are even areas where you see very little at all, usually in the heart of the big cities.

The earliest ground frost can be anywhere as early as 26th September in some parts of the UK. Most places will see some frost by mid-November. But you can use one of the calculators to find the exact area you live in and check the average date for the first frost to get a more accurate idea.

Average first frost dates by USDA zone

• Zone 1 July 15
• Zone 2 August 15
• Zone 3 September 15
• Zone 4 September 15
• Zone 5 October 15
• Zone 6 October 15
• Zone 7 October 15
• Zone 8 November 15
• Zone 9 December 15
• Zone 10 December 15
• Zone 11 No frost

How temperature affects cool-season vegetables

Don’t get too worked up about the prospect of frost. Unlike tender annuals like tomatoes, most cool-season crops can withstand some cold once they’re established and growing.

They won’t grow as much in the winter, but they will keep producing until the earth freezes. That is generally at least a few weeks after a frost. However, if you want to keep your plants warmer and growing faster into the fall, cover them up at night beforehand.

Cold protection tip for fall vegetables

Soil holds heat during the day. As the sun sets and the air temperature falls, heat is released from the soil. When it’s cold outside, a fabric cover can protect that heat closer to your plants. Even a sheet or piece of floating row cover will suffice.

Keep the cloth away from the plants for the greatest protection. If it gets wet, it may pass cold from the air to the leaf and harm it. The cover is kept in place by an upturned wire basket.

To trap the most heat, place the covering over the plants just as the sun sets in the evening. After the sun rises, remove it.

What cool weather vegetables to plant

Some plants stand out as being the best candidates if you want to grow some cool season vegetables.

The Cabbage Family

The cabbage family includes cabbages, broccoli, cauliflower and kales which all produce white or yellow flowers when the plant goes to seed.

The seeds will germinate in approximately a week and may be sowed in a protected garden bed about a month before your last frost date. If the weather is still chilly, cover the plants with a row cover or cloche to keep them warm.

In areas with mild winters, you may also grow these crops in your fall garden. In September, transplant the seedlings and place them in your garden to avoid overheating.

The seedlings settle faster in the summer months when the earth is warm and cool fall temperatures assist them to grow. A second crop is produced about 60 days after planting, if need be. If an early frost threatens, have a frost protection wrap on hand.

Collards are a winter-hardy plant that can survive temperatures as low as 0°F. The flavour of collards increases with a sprinkling of frost, which sweetens the greens. Plant 6 to 8 weeks before the first frost.

Kale is mild, delicate, and frost-kissed kale is nothing like the bitter greens you might have encountered at the store. This hardy crop is ideal for cold environments with a temperature range down to 0°F. Plant it 6 to 8 weeks before the first freeze.

The Onion Family

Onions, shallots, and leeks are the primary members of this family. They take a long period to mature and require many weeks to reach maturity.

In the garden, onion and shallot sets can be planted about a month before your last frost date, as well as sown for a fall crop. They may also be grown in late winter for a spring harvest.

Salad Vegetables

In the spring, there are a variety of varieties of cool weather lettuce mixes including mustard greens that grow in gardens. Indoor propagation may begin two months before the last frost.

Cover the seedlings with a cloth on cool nights about a month before the last frost. Seeds may also be sown for a longer harvest. Autumn harvest is another great idea.

On the other side of the spectrum, most of the cold-weather veggies may survive a light frost, but keep a cloth on hand for early frosts and late freezes. Winter vegetables will keep your dinner table full of fresh, nutritious veggies for at least a few weeks longer by extending the season.

Spinach can grow in temperatures as low as 0°F and becomes sweeter as the weather grows colder. If you want the leaves to look good, provide some protection (such as row cover) for the plants. Plant 6 to 8 weeks before your first frost.

Carrots

This plant’s foliage changes colour and texture as the weather gets colder. The leaves become greener and more glossy, and their structure becomes tighter.

Winter cold stimulates this plant to produce more sugars, which act as a sort of antifreeze to protect the roots from freezing. Carrot roots are resistant to temperatures down to 15°F; however, the tops may be more vulnerable.

Finding the best cool weather vegetables

When you are looking to plant cool weather vegetables, always think about what you can use in your recipes or can give to friends. That way you’ll have a supply of useful vegetables all year round.