First and last frost dates (and why they matter)

For any gardener, knowing the average first and last frost dates is essential. These dates help you plan when to plant and harvest, ensuring your plants thrive while avoiding potential frost damage.

The first signs of spring can be difficult for many gardeners who are starting their seed plan. Knowing when to plant is a great way to avoid any issues and prepare for them. 

In many cases, this means getting plants in the ground when the average last frost date passes. This will change based on your area, but it is a crucial first step to ensure you enjoy a successful spring garden.

What is a frost date in gardening?

A great way to prevent damage to your plants and flowers is by understanding when to plant. A frost date refers to when temperatures drop to 32°F or lower, which is cold enough to harm or kill plants. The last frost date in spring marks the end of the cold season and signals a good time to start planting. 

In most cases, you should wait until the average last frost date has passed before putting plants in the ground. This date varies by region but is a crucial first step for a successful garden. Read on to understand more about frost dates and why they are important.

What are the average first and last frost dates by zone?

The last frost date refers to the final spring frost, while the first frost date signals when frost typically returns in fall. These dates vary depending on your location, elevation, and whether you're in an urban or rural area. Cities tend to warm up faster in spring, causing their frost dates to be earlier than those in rural areas.

To determine your frost dates, use the USDA Plant Hardiness Zone Map, which provides region-specific climate data.

By getting the timing right, your initial plantings will be protected from cold temperatures, ensuring they have the best chance to survive.

Vegetables standing strong against winter chill. (Source: iStock)

How does the last frost affect vegetables?

The last frost date is critical for determining when to plant your vegetable garden. During spring, nighttime temperatures can still be too cold for many plants.

Some hardy vegetables like lettuce, carrots, cabbage, spinach, and radishes can tolerate lower temperatures. However, warm-season crops such as cucumbers, tomatoes, butternut squash, and pumpkins are more vulnerable to frost damage.

How do you find your specific last frost date?

Thanks to various online resources, determining your first and last frost dates is easy.

• USDA Plant Hardiness Zone Map: This map helps you understand the average temperatures in your region.

• The Old Farmer’s Almanac Frost Dates Calculator: Enter your ZIP code to get average frost dates for your location.

• National Gardening Association Frost Dates Tool: This frost dates tool provides detailed probability charts for frost dates.

It’s important to remember that frost date data is based on historical averages, meaning frost can still occur outside of these estimates. To be safe, consider allowing a buffer before planting.

Frosty mornings challenge young plants. (Source: iStock)

How do you know when it's the last frost?

Many online resources track frost dates, including the National Weather Service. However, weather patterns can be unpredictable, so it’s always best to monitor your local forecast closely.

Which plants are sensitive to frost?

Many tender plants and crops are susceptible to frost damage, including:

Fruits & Vegetables

• Avocados

• Citrus trees

• Tomatoes

• Pumpkins

• Sweet potatoes

• Cucumbers

• Eggplants

• Corn

Plants & Flowers

• Fuchsia

• Begonias

• Impatiens

• Geraniums

• Succulents

• Tropical plants

If you plan on growing any of these, be sure to check your local last frost date to avoid damage.

Which crops and plants can withstand frost?

The U.S. climate supports a variety of frost-hardy fruits, vegetables, and plants. These resilient varieties can extend your growing season and ensure a successful harvest even in colder months.

Fruits & Vegetables

• Kale

• Carrots

• Broccoli

• Peas

• Brussels sprouts

• Spinach

• Garlic

• Radishes

Plants

• Pansies

• Violas

• Coneflowers

• Sedum

• Holly

• Yew

• Juniper

• Winterberry

By choosing frost-tolerant plants, you can keep your garden thriving throughout the colder seasons.

How can I protect my plants from frost?

Home gardeners can protect their plants from frost in several ways:

• Mulching: Organic mulch like straw or bark helps insulate the soil and retain warmth, protecting roots from frost.

• Frost covers or mini-greenhouses: Use horticultural fleece, cloches, or even old bedsheets as protective covers. Remove them during the day to allow airflow.

• Watering plants in the morning: Moist soil retains heat better, so watering before a frost can help keep roots warm.

• Using plastic bottles or containers: Covering small plants with plastic bottles can create a mini greenhouse effect, trapping warmth and shielding delicate leaves.

Ensure a thriving garden

There are many different things to be aware of to ensure your garden thrives; it’s one of the reasons why we have the gardening hub, a place for helpful resources to help you have the greenest of thumbs.

Need an extra hand? Plenty of Airtasker gardening experts can offer their services. From general yard work to other outdoor areas that need attention like pool maintenance, there is always a Tasker ready and willing to help.