Vegetable Planting Guide for Zone 4

Zone 4 covers parts of northern states like Minnesota, Wisconsin, and northern Colorado. The growing season typically lasts from mid-May to late September, with about five months to grow cold-resistant crops. Proper timing and crop selection are important for making the most of this growing window.

Last Frost and First Frost Dates

The average last frost in this region is mid-May, while the first frost usually arrives in late September. Transplant hardy crops like broccoli and kale 1-2 weeks after the last frost to avoid any lingering cold. Root vegetables like carrots and radishes can be sown just after the last frost.

Last Frost Date	First Frost Date
Mid-May	Late September

These dates can vary slightly based on local conditions, so it’s always a good idea to check your local weather for accurate frost predictions.

Planting Dates

The growing season in this region is short, but by carefully timing your planting, you can ensure a productive harvest. Below are the optimal planting times for key crops:

Vegetable	Planting Indoors	Transplant Outdoors	Direct Sow Outdoors	Harvest Period
Broccoli	Early April	Mid-May	Not Recommended	July – September
Cabbage	Early April	Mid-May	Not Recommended	July – September
Radishes	N/A	N/A	Mid-May	June – July
Carrots	N/A	N/A	Mid-May	July – September
Kale	Early April	Mid-May	Not Recommended	July – September
Spinach	Mid-April	Mid-May	Not Recommended	July – September

Find In-depth growing guides for cold hardy plants here:

The Importance of Good Soil

Before starting to grow, it’s essential to assess the condition of the soil in your garden. The best soil is a blend of mineral-rich dirt and organic matter. In my garden, I compost as much as possible to enrich the soil with nutrients. I use both hot composting for food scraps and cold composting for organic garden waste.

Also, ensure that your garden gets enough sunlight and that the soil drains well. Treat your soil well, plan your crops based on your climate, and you’ll be set up for a productive garden season.

If you don’t have the time or space to compost, you can purchase compost from garden centers or take advantage of community composting programs. Learn more about community composting here.

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Hot Composting

Hot composting can help break down organic matter quickly, even in cold climates. One hot composter for cold climates is the Exaco Aerobin 400 Insulated Compost Bin. This 113-gallon composter is insulated to retain heat and does not require turning thanks to its patented “lung” system. It also has a built-in reservoir that collects compost tea, which can be diluted and used as fertilizer.

The Exaco Aerobin 400 Insulated Compost Bin is available for $343.79. Check the latest price on Amazon.

Extending the Season

In colder climates, extending the growing season is crucial to maximize your harvest. Greenhouses and cold frames are popular options for early planting and keeping crops growing into the fall. Cold frames are a low-cost solution that uses sunlight to warm the soil, while greenhouses offer more control but come with higher setup costs.

This 10×12 FT greenhouse from Amazon can help extend the growing season. It’s available for $999. Check the latest price on Amazon.

Using Mulch

Mulch acts as a protective blanket for the soil, regulating temperature and moisture. In cold climates, where nights can still be chilly in the middle of summer, mulch helps keep plant roots warmer during temperature dips. Organic mulch, such as straw, leaves, or compost, insulates the soil and gives you a little more growing time, which is crucial in short growing seasons.

Mulch also helps retain moisture by reducing evaporation, which means less time watering and less stress on plants. It is especially helpful in raised beds and containers where soil dries out faster. Additionally, mulch controls weeds, stopping them from competing with your vegetables for nutrients.

As mulch breaks down, it feeds the soil, boosting its fertility. Choose your mulch based on your garden’s needs—straw, leaves, or compost are all excellent choices for retaining warmth and moisture. In windy areas, securing your mulch with stones or using heavier materials like bark chips can help prevent it from blowing away.

Cost Benefits

Rather than buying new mulch every year, creating your own supply can cut down on long-term costs. You can use an electric chipper to break down organic material from your yard to create mulch, reducing reliance on store-bought products and yard professionals.

The Sun Joe CJ603E Wood Chipper is an affordable and effective option for creating mulch from branches up to 1.7 inches thick. It’s available for $199. Check the latest price on Amazon.

States that fall in under Zone 4

• 4a: Alaska,Colorado, Idaho, Iowa, Maine, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New York, North Dakota, South Dakota, Vermont, Wisconsin, Wyoming
• 4b: Alaska, Colorado, Idaho, Illinois, Indiana, Iowa, Maine, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New York, North Dakota, Ohio, Pennsylvania, South Dakota, Vermont, Wisconsin, Wyoming

The next hardiness zone is 5