Your Average First Frost Date

Do you know your city’s average first frost date? Dates listed below are estimated light frost dates (when temperatures are between 29°–32°F). Light frosts may kill tender plants, but cause little destruction to hardier vegetation.

The probability of a frost occurring after the spring date or before the fall frost date listed below is 30%, which means it could occur before or after the dates listed. It’s best to take precautions and protect tender plants during early spring and late fall.

Different Types:

• Light freeze: 29 degrees F to 32 degrees F – tender plants killed, with little destructive effect on other vegetation.
• Moderate freeze: 25 degrees F to 28 degrees F – widely destructive effect on most vegetation, with heavy damage to fruit blossoms and tender and semi-hardy plants.
• Severe freeze: 24 degrees F and colder – damage to most plants.

RELATED: How to protect your plants when frost is coming

*Higher elevations in Hawaii do occasionally see at-or-near freezing temperatures, but definitive dates are not available.

Source for dates: United States Annual/Seasonal Climate Normals (1991-2020).

How To Prepare for First frost

As the growing season winds down and the first frost looms, protect your plants and prepare their gardens for winter. Here’s a breakdown of some of the key things to do:

Cover Your Plants

The most common and effective method for extending the season for frost-sensitive plants is to cover them. Here are a few ways:

• Row covers: Made of lightweight, non-woven polyester, these are designed specifically for gardening and come in different thicknesses. They can be draped directly over plants or supported by hoops to create a tunnel.
• Old bedsheets, blankets, or tarps: These common household items can be used for a quick, overnight solution. It’s best to avoid plastic, as it can trap too much heat during the day and damage plants.
• Containers: Buckets, pots, or even large cardboard boxes can be inverted over smaller plants to trap ground heat.

Important tip: The covering should ideally not touch the foliage to prevent frost damage where the material makes contact. It should be secured to the ground with stakes, bricks, or rocks to trap in the heat.

Water Thoroughly

This may seem counterintuitive, but watering the soil thoroughly in the late afternoon or early evening before a frost can help. Wet soil holds and radiates heat more effectively than dry soil, which can keep the air around the plants a few degrees warmer.

Bring Plants Indoors

Potted plants, especially tropical ones and tender annuals, are brought inside when nighttime temperatures consistently drop below 50°F (10∘C). This is a simple and reliable way to save them for the next season.

Harvest Tender Crops

Plants that are very sensitive to frost, such as tomatoes, peppers, basil, beans, cucumbers, and squash, are harvested completely before the first frost hits. Pick all remaining fruits, even if they are still green, as they can often ripen indoors.

Leave Frost-Tolerant Crops

Some vegetables and herbs, like kale, collards, Brussels sprouts, carrots, spinach, and Swiss chard, can actually have their flavor improved by a light frost. These are often left in the garden for later harvest.

Clean-up Your Garden

Dead and spent annual plants are removed from the garden beds to prevent pests and diseases from overwintering. This is also a good time to pull any remaining weeds.

How To Prepare Your Garden for Winter

Here are a few suggestions to prepare your garden for winter:

Add Mulch

Adding a thick layer of mulch, such as straw, leaves, or compost, to garden beds helps to insulate the soil and protect the roots of perennials and cold-hardy vegetables. This helps maintain soil temperature and moisture.

Plant Bulbs

The fall is the ideal time to plant spring-blooming bulbs like tulips and daffodils. The cool soil allows them to establish a strong root system before the ground freezes.

Winterize Your Equipment

Hoses are drained and coiled, and irrigation systems are shut off and blown out to prevent water from freezing and cracking the pipes. Outdoor faucets may be covered with insulated protectors.

RELATED: How to Winterize Lawnmower and Outdoor Equipment

Amend Your Soil

Add compost or other organic matter to your garden beds in the fall. This allows the nutrients to break down over the winter and enrich the soil for the next growing season.

Join the Discussion

What are some ways that you prepare your garden for the first frost?

Share your tips and tricks in the comments!

We all learn from each other.