What is USDA hardiness Zone 4?
USDA hardiness Zone 4 includes regions with average minimum temperatures ranging from -30°F to -20°F (-34.4 °C to -28.9°C). It covers parts of the Northern United States and Southern Canada. Gardeners in this zone experience cold winters and a short growing season but can still cultivate a variety of plants with the right techniques.
Climate and growing conditions
- Cold winters with deep frost and snow cover.
- Short growing season, generally 100 to 150 days from the last frost in the spring to the first frost in the fall.
- The first frost date typically occurs between September 21 and October 7
- The last frost date ranging from April 24 to May 12
- Common weather challenges: Freeze-thaw cycles, unexpected frosts, and heavy snowfall.
What is the difference between Zone 4a and Zone 4b?
The two subtypes of USDA Hardiness Zone 4, 4a and 4b, are based on differences in average minimum temperatures.
- Zone 4a: The average minimum temperature ranges between -25°F and -30°F (-31.7°C to -34.4°C).
- Zone 4b: The average minimum temperature ranges between -20°F and -25°F (-28.9°C to -31.7°C).
This means that Zone 4b has a slightly milder winter climate than Zone 4a. Plants that tolerate colder temperatures may survive more easily in Zone 4b, while Zone 4a may require stronger frost protection measures. When choosing plants, it’s essential to consider these temperature differences to ensure they are well-suited to your zone.
Weather conditions
Winter conditions
Condition | Details |
Temperatures | Can reach -30°F to -20°F (-34°C to -29°C), especially in sub-zones 4a and 4b. |
Duration | Winters are long, and the ground remains frozen for months. |
Snow | Typically fluffy, low moisture snowfall, accumulating throughout the season. |
Summer conditions and precipitation
Condition | Details |
Temperatures | Summer can be warm, with temperatures ranging from 70°F to 85°F (21°C to 29°C). Hot spells above 90°F (32°C) are possible but less frequent. |
Growing season | Short, typically 100–140 days (from mid-April to late September). Careful selection of plants is needed due to the limited growing period. |
Precipitation | 20-40 inches (50-100 cm) annually. Snowfall is significant but low in moisture. Spring and summer bring adequate rainfall for plant growth. |
Best plants for Zone 4
Gardeners in Zone 4 should select cold-hardy plants that can thrive in cooler temperatures and short seasons.
Vegetables for planting
✅ Spinach – A hardy vegetable that grows quickly and tolerates cooler temperatures and frost
✅ Pea – A cool-weather crop that is frost-tolerant and easy to grow
✅ Radish – Fast-growing, frost-tolerant, and ideal for quick harvests
✅ Onion – Grows well in cool soil, available from seeds or sets
✅ Cauliflower – Prefers cool conditions and is frost-tolerant, making it reliable in colder climates
✅ Broccoli – Thrives in cool climates, tolerates frost, and grows efficiently
✅ Potato – Grows best in cool soil, and is frost-tolerant
✅ Beets – Grows quickly in cool weather and can withstand frost
✅ Arugula – A fast-growing leafy green that prefers cool temperatures and can handle frost
✅ Peas – Frost-tolerant and well-suited for cooler climates
✅ Potatoes – Thrive in cool conditions, tolerating some frost
Herbs to try
✅ Savory – A hardy herb that tolerates Zone 4 winters and grows well in the cooler months.
✅ Borage – Tolerates the cooler temperatures of Zone 4 and can be grown as an annual or perennial.
✅ Parsley – Biennial herb that can survive Zone 4’s winters if protected, or treated as an annual.
✅ Fennel – Typically grown as an annual in Zone 4, though some hardy varieties may survive the winter if provided adequate protection.
✅ Thyme – A hardy perennial herb, especially winter-hardy varieties like English thyme can tolerate cold temperatures.
✅ Oregano – A hardy perennial that thrives in Zone 4 and can be left to overwinter with proper care.
✅ Mustard – Grows well in cooler climates, and Zone 4’s short season is ideal for mustard greens.
✅ Lavender – While not as cold-hardy as some herbs, it can be grown in Zone 4 with winter protection, especially in a sheltered area.
✅ Rosemary – Generally considered a tender perennial in Zone 4, it can be grown in pots and brought indoors during winter for protection.
Flowers to grow in Zone 4
Add spring and summer charm with these cold-hardy favorites:
✅ Crocus – Among the first to bloom through late snow
✅ Daffodils – Bright, cheerful, and reliable every spring
✅Tulips – Classic spring blooms in every color imaginable
✅ Dutch Iris – Elegant, sword-shaped flowers in blues and purples
✅ Hyacinths – Fragrant and compact, great for borders and beds
✅ Peony – Long-lived perennials with lush, romantic blooms
Cold-hardy fruit trees & berries
✅ Honeycrisp Apple – Crisp, flavorful, and cold-tolerant
✅ Alderman Plum – Juicy fruit and lovely spring blossoms
✅ North Star Cherry – Compact, self-pollinating, and ideal for small gardens
✅ Blueberries – Acid-loving shrubs that thrive in Zone 4 soil
✅ Mulberry tree – Fast-growing and attractive to birds and pollinators
✅ Moongold Apricot – Needs a protected spot but rewards with golden fruit
✅ Nova Pear – Exceptionally cold-hardy with sweet, firm fruit
Planting & harvesting schedule
Below is a simplified schedule for common crops:
Plant | Sow Indoors | Transplant Outside | Harvest Time |
Spinach | May 12 | May 22 | June-September |
Pea | May 30 | June 5 | August-September |
Broccoli | May 27 | June 6 | July-September |
📅 Want a customized schedule? Try our planting calendar!
Protection tips
For both vegetables and herbs, it’s crucial to select varieties known for their cold hardiness. This will ensure they can withstand the colder months typical in Zone 4. To give them the best chance of thriving, consider taking extra protective measures like row covers or mulch. These can shield plants from frost and extend their growing period.
What are the best solutions against winter snow and ice in my garden?
Mulching: Mulch (such as straw, leaves, or wood chips) helps maintain soil temperature, prevents deep freezing of the soil, and protects plants from temperature extremes. Additionally, it prevents direct contact between snow, ice, and the plant roots.
Protection with covers or blankets: If the snow layer becomes thicker or if there is a risk that ice could damage your plants, you can use covers or plastic sheets. These help keep the plants warm and prevent excessive moisture buildup.
Covering trees and shrubs: If you have trees and shrubs in your garden, the weight of the ice can damage the branches. When removing snow and ice, be careful to gently remove the ice layer to avoid breaking the fragile branches. It is advisable to cover the branches with materials that help prevent ice buildup.
Removing snow around plants: If too much snow accumulates in the garden, it’s important to be aware that the buildup can harm plants by blocking sunlight. Clear the snow accumulations so that the plants can access light and air.
