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Zone 4b Planting Calendar

Zone 4b Zone 4b August

What to do in August

Here's what deserves your attention in Zone 4b this month. Everything below is tailored to Zone 4b and timed around your local frost dates.

Avg. last frost May 11
Avg. first frost October 2
  1. Pick basil, carrots, and cucumber

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

  2. Start your fall crops: alliums, crocus, and daffodils

    Keep young seedlings shaded and moist in summer heat. A row of taller crops works as natural shade.

A few tasks this August that'll pay off in September
  • First harvests: basil, cucumber, and green beans
Download your personalised Zone 4b planting plan →

Zone 4b has an average minimum temperature range of -25°F to -20°F. The average last spring frost is around May 1 and the first fall frost is around October 3, giving you approximately 155 days in the growing season.

There are 196 plants in our database that grow well in Zone 4b.

Zone 4b Moderate season
155 days
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Last Spring Frost May 1
➔ 155 growing days ➔
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First Fall Frost October 3
Zone 4b Frost Countdown
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Last Frost: May 1 First Frost: Oct 3

States That Include Zone 4b

Many states span multiple zones. The states highlighted below contain areas classified as Zone 4b.

AL — Zone 7b AL AR — Zone 7b AR AZ — Zone 8a AZ CA — Zone 9a CA CO — Zone 5a CO CT — Zone 6b CT DE — Zone 7a DE FL — Zone 9a FL GA — Zone 7b GA IA — Zone 5a IA ID — Zone 5b ID IL — Zone 5b IL IN — Zone 6a IN KS — Zone 6a KS KY — Zone 6b KY LA — Zone 8b LA MA — Zone 6a MA MD — Zone 7a MD ME — Zone 4b ME MI — Zone 5b MI MN — Zone 4a MN MO — Zone 6a MO MS — Zone 8a MS MT — Zone 4b MT NC — Zone 7a NC ND — Zone 3b ND NE — Zone 5a NE NH — Zone 5a NH NJ — Zone 7a NJ NM — Zone 6b NM NV — Zone 6b NV NY — Zone 5b NY OH — Zone 6a OH OK — Zone 7a OK OR — Zone 7a OR PA — Zone 6a PA RI — Zone 6b RI SC — Zone 8a SC SD — Zone 4a SD TN — Zone 7a TN TX — Zone 8a TX UT — Zone 5b UT VA — Zone 7a VA VT — Zone 4b VT WA — Zone 7a WA WI — Zone 4b WI WV — Zone 6a WV WY — Zone 4a WY AK — Zone 2a AK HI — Zone 11a HI
Zones: 1 2 3 4 5 6 7 8 9 10 11

Growing Season Comparison

What to Plant Right Now in Zone 4b

Based on August 2026 planting windows.

Acorn Squash Harvest Aug 14 – Sep 18 Ageratum Harvest Jul 3 – Sep 18 Alliums Fall Sowing Aug 22 – Sep 5 Alpine Strawberries Harvest Aug 28 – Oct 23 Amaranth Harvest Aug 21 – Oct 9 Anise Harvest Jul 24 – Sep 18 Arugula Harvest Jun 5 – Aug 7 Astilbe Harvest Aug 7 – Oct 2

See all August plantings →

All Planting Windows at a Glance

This chart shows when to start, transplant, sow, and harvest every plant in Zone 4b.

Vegetables for Zone 4b

Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Acorn Squash Mar 20 May 15 May 22 Aug 14 – Sep 18 80–100
Amaranth Feb 27 May 15 May 22 Aug 21 – Oct 9 90–120
Arugula Mar 20 Apr 24 May 1 Jun 5 – Aug 7 30–50
Asparagus — — May 15 — 730–1095
Beets — Apr 24 — Jun 19 – Jul 17 50–70
Belgian Endive Mar 20 Apr 24 May 1 Aug 21 – Sep 25 110–150
Black Beans — May 15 — Aug 14 – Oct 2 90–120
Bok Choy Mar 20 Apr 24 May 1 Jun 12 – Jul 17 40–60
Broccoli Mar 20 Apr 24 May 1 Jul 3 – Aug 14 60–90
Broccoli Rabe Mar 20 Apr 24 May 1 Jun 12 – Jul 17 40–60
Brussels Sprouts Mar 20 Apr 24 May 1 Jul 31 – Sep 25 90–130
Butternut Squash Mar 20 May 15 May 22 Aug 21 – Sep 25 85–110
Cabbage Mar 20 Apr 24 May 1 Jul 3 – Aug 28 60–100
Carrots — Apr 24 — Jun 26 – Jul 31 60–80
Cauliflower Mar 20 Apr 24 May 1 Jun 26 – Aug 28 55–100
Celeriac Mar 20 Apr 24 May 1 Aug 14 – Sep 18 100–120
Celery Mar 20 Apr 24 May 1 Jul 24 – Sep 18 80–120
Celtuce Mar 20 Apr 24 May 1 Jul 3 – Aug 14 60–90
Chard Mar 20 Apr 24 May 1 Jun 26 – Aug 14 50–60
Chickpeas Mar 20 Apr 24 May 1 Jul 24 – Sep 4 80–110
Chicory Mar 20 Apr 24 May 1 Jul 3 – Aug 14 60–85
Chinese Cabbage Mar 20 Apr 24 May 1 Jun 26 – Jul 24 50–70
Christmas Lima Beans Feb 27 May 15 May 22 Aug 14 – Sep 18 80–100
Collard Greens Mar 20 Apr 24 May 1 Jun 26 – Aug 28 55–75
Corn — May 15 — Jul 17 – Sep 11 60–100
Cress Mar 20 Apr 24 May 1 May 15 – Jun 5 14–21
Crookneck Squash Mar 20 May 15 May 22 Jul 10 – Aug 7 45–60
Crosne — Apr 24 — Sep 25 – Sep 18 150–200
Cucumber Mar 20 May 15 May 22 Jul 17 – Sep 11 50–70
Daikon — Apr 24 — Jun 19 – Jul 17 50–70
Delicata Squash Mar 20 May 15 May 22 Aug 14 – Sep 18 80–100
Edamame — May 15 — Jul 31 – Sep 11 75–100
Endive Mar 20 Apr 24 May 1 Jun 19 – Jul 24 45–65
Escarole Mar 20 Apr 24 May 1 Jun 26 – Jul 24 50–70
Fava Beans Mar 20 Apr 24 May 1 Jul 17 – Aug 28 75–100
Fennel Feb 27 May 15 May 22 Jul 24 – Sep 4 60–90
Garlic — — — Nov 21 – Jan 16 90–240
Green Beans — May 15 — Jul 10 – Sep 4 50–65
Horseradish — — May 15 Sep 18 – Oct 9 120–180
Hubbard Squash Mar 20 May 15 May 22 Sep 4 – Oct 9 100–120
Kabocha Mar 20 May 15 May 22 Aug 21 – Sep 18 85–100
Kai Lan Mar 20 Apr 24 May 1 Jun 19 – Jul 17 45–60
Kale Mar 20 Apr 24 May 1 Jun 26 – Aug 21 50–70
Kidney Beans — May 15 — Aug 14 – Sep 18 85–110
Kohlrabi Mar 20 Apr 24 May 1 Jun 19 – Jul 24 45–65
Komatsuna Mar 20 Apr 24 May 1 Jun 5 – Jul 10 35–50
Leeks Mar 20 Apr 24 May 1 Jul 31 – Sep 25 90–150
Lentils Mar 20 Apr 24 May 1 Jul 24 – Sep 4 80–110
Lettuce Mar 20 Apr 24 May 1 Jun 5 – Aug 14 30–60
Lima Beans — May 15 — Jul 17 – Aug 28 60–90
Mache Mar 20 Apr 24 May 1 Jun 12 – Jul 17 40–60
Melon Mar 20 May 15 May 22 Jul 31 – Sep 18 70–100
Microgreens Mar 20 Apr 24 May 1 May 8 – Jun 5 7–21
Mitsuba Mar 20 Apr 24 Apr 24 Jun 19 – Aug 14 50–70
Mizuna Mar 20 Apr 24 May 1 Jun 5 – Jul 3 30–45
Mustard Greens Mar 20 Apr 24 May 1 Jun 5 – Aug 7 30–50
Napa Cabbage Mar 20 Apr 24 May 1 Jun 26 – Jul 31 55–75
Onion Mar 20 Apr 24 May 1 Jul 31 – Sep 18 90–120
Pac Choi Mar 20 Apr 24 May 1 Jun 12 – Jul 10 40–55
Parsnip — Apr 24 — Aug 7 – Sep 18 100–130
Patty Pan Squash Mar 20 May 15 May 22 Jul 10 – Aug 7 45–60
Peas Mar 20 Apr 24 May 1 Jun 26 – Aug 21 55–70
Peppers Feb 13 May 15 May 22 Jul 24 – Oct 2 60–90
Pole Beans Feb 27 May 15 May 22 Jul 17 – Sep 11 55–70
Potatoes Feb 27 May 15 May 22 Jul 31 – Oct 9 70–120
Pumpkin Mar 20 May 15 May 22 Aug 21 – Oct 9 85–120
Purslane Mar 20 Apr 24 May 1 Jun 12 – Jul 17 40–60
Radicchio Mar 20 Apr 24 May 1 Jul 3 – Aug 7 60–80
Radish — Apr 24 — May 22 – Jun 12 22–35
Rhubarb — — May 29 — 365–730
Romanesco Mar 20 Apr 24 May 1 Jul 17 – Aug 28 75–100
Rutabaga — Apr 24 — Jul 17 – Aug 21 80–100
Salsify — Apr 24 — Aug 7 – Sep 18 100–130
Savoy Cabbage Mar 20 Apr 24 May 1 Jul 10 – Sep 4 70–110
Scallions Mar 20 Apr 24 May 1 Jun 26 – Jul 24 50–70
Scarlet Runner Beans Feb 27 May 15 May 22 Jul 24 – Aug 28 60–80
Shallot Mar 20 Apr 24 May 1 Jul 31 – Sep 18 90–120
Shiso Mar 6 May 8 May 22 Jul 17 – Sep 11 50–70
Snap Peas Feb 27 May 15 May 22 Jul 17 – Sep 11 55–70
Snow Peas Mar 20 Apr 24 May 1 Jun 26 – Aug 21 50–65
Soybeans — May 15 — Aug 7 – Oct 2 80–120
Spaghetti Squash Mar 20 May 15 May 22 Aug 21 – Sep 18 85–100
Spinach Mar 20 Apr 24 May 1 Jun 5 – Aug 7 35–50
Squash (Summer) Mar 20 May 15 May 22 Jul 10 – Sep 11 45–65
Squash (Winter) Mar 20 May 15 May 22 Aug 14 – Oct 9 80–120
Sunchoke — — May 15 Sep 4 – Oct 9 110–150
Sweet Corn — May 15 — Jul 17 – Aug 28 60–90
Tatsoi Mar 20 Apr 24 May 1 Jun 5 – Jul 10 35–50
Tomatillo Feb 27 May 15 May 22 Jul 24 – Oct 2 60–85
Tomatoes Feb 27 May 15 May 22 Jul 24 – Oct 2 60–85
Turnip — Apr 24 — Jun 5 – Jul 10 40–60
Watercress Mar 20 Apr 24 May 1 Jun 12 – Jul 17 40–60
Watermelon Mar 20 May 15 May 22 Jul 31 – Sep 18 70–100
Wax Beans — May 15 — Jul 10 – Sep 4 50–65
Zucchini Mar 20 May 15 May 22 Jul 10 – Sep 4 45–60

Fruits for Zone 4b

Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Alpine Strawberries — — May 29 Aug 28 – Oct 23 90–180
Aronia — — May 29 — 730–1095
Blueberries — — May 29 — 730–1095
Cantaloupe — — May 29 Aug 7 – Sep 11 70–90
Cranberries — — May 29 — 730–1095
Currants — — May 29 — 730–1095
Elderberries — — May 29 — 730–1095
Goji Berries — — May 29 — 730–1095
Gooseberries — — May 29 — 730–1095
Grapes — — May 29 — 730–1095
Ground Cherry — — May 29 Aug 7 – Oct 2 65–80
Hardy Kiwi — — May 29 — 1095–1825
Haskaps — — May 29 — 730–1095
Honeydew — — May 29 Aug 21 – Oct 2 80–110
Jostaberry — — May 29 — 730–1095
Lingonberries — — May 29 — 730–1095
Medlar — — May 29 — 1095–1825
Mulberries — — May 29 — 730–1825
Persimmon — — May 29 — 1095–2555
Raspberries — — May 29 — 365–730
Serviceberries — — May 29 — 730–1095
Strawberries — — May 29 Aug 28 – Oct 23 90–365

Herbs for Zone 4b

Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Angelica Mar 20 Apr 24 Apr 24 — 365–730
Anise Mar 20 Apr 24 Apr 24 Jul 24 – Sep 18 90–120
Basil Mar 6 May 8 May 22 Jul 17 – Sep 18 50–75
Bee Balm — — May 8 Aug 7 – Oct 2 90–120
Borage Mar 20 Apr 24 Apr 24 Jun 19 – Aug 7 50–60
Caraway Mar 20 Apr 24 Apr 24 — 365–450
Catnip — — May 8 Jul 10 – Sep 11 60–80
Chamomile Mar 20 Apr 24 Apr 24 Jun 26 – Sep 4 60–90
Chervil Mar 20 Apr 24 Apr 24 Jun 5 – Aug 7 40–60
Chives — — May 8 Jul 10 – Sep 18 60–90
Cilantro Mar 20 Apr 24 Apr 24 Jun 5 – Aug 7 40–60
Comfrey — — May 8 Jul 10 – Sep 18 60–90
Dill Mar 20 Apr 24 Apr 24 Jun 5 – Aug 7 40–60
Fennel (herb) Mar 20 Apr 24 Apr 24 Jun 26 – Sep 4 60–90
Garlic Chives — — May 8 Jul 10 – Sep 18 60–90
Horehound — — May 8 Jul 24 – Sep 18 75–90
Hyssop — — May 8 Jul 17 – Sep 18 70–90
Lemon Balm — — May 8 Jul 10 – Aug 28 60–70
Lovage — — May 8 Jul 17 – Sep 18 70–90
Mint — — May 8 Jul 10 – Sep 18 60–90
Oregano — — May 8 Jul 10 – Sep 18 60–90
Parsley Mar 20 Apr 24 Apr 24 Jun 26 – Aug 28 60–80
Rue — — May 8 Jul 17 – Sep 18 70–90
Sage — — May 8 Jul 24 – Sep 18 75–90
Savory — — May 8 Jul 3 – Aug 28 50–70
Sorrel Mar 20 Apr 24 Apr 24 Jun 5 – Aug 7 40–60
Tarragon — — May 8 Jul 10 – Sep 18 60–90
Thai Basil Mar 6 May 8 May 22 Jul 17 – Sep 18 50–75
Thyme — — May 8 Jul 17 – Sep 18 70–90
Valerian — — May 8 Sep 11 – Oct 2 120–180

Flowers for Zone 4b

Plant Start Indoors Direct Sow Transplant Harvest Days to Maturity
Ageratum Mar 13 May 8 May 8 Jul 3 – Sep 18 60–75
Alliums — — — Sep 26 – Oct 24 28–42
Astilbe Feb 20 — May 15 Aug 7 – Oct 2 70–100
Bachelor's Button Mar 13 Apr 17 May 1 Jul 3 – Sep 4 60–90
Begonias Feb 13 — May 8 Jul 17 – Sep 25 70–90
Black-eyed Susan Feb 20 May 1 May 15 Aug 7 – Oct 23 60–80
Bleeding Hearts Feb 20 — May 15 Jul 10 – Aug 21 60–90
Calendula Mar 13 Apr 17 May 1 Jun 19 – Sep 4 50–70
Celosia Mar 27 May 15 May 15 Jul 17 – Oct 2 60–90
Columbine Feb 20 May 15 May 15 Jul 10 – Aug 28 70–100
Coreopsis Feb 20 May 8 May 15 Jul 31 – Oct 23 60–80
Cosmos Apr 3 May 8 May 8 Jul 17 – Oct 9 60–90
Crocus — — — Jun 27 – Jul 25 10–20
Daffodils — — — Jul 4 – Aug 1 20–40
Dahlias Apr 3 May 15 May 15 Aug 14 – Oct 23 70–120
Daylily Feb 20 — May 15 Aug 14 – Oct 23 60–90
Dianthus Feb 27 Apr 10 Apr 24 Jun 12 – Aug 21 60–80
Echinacea (Purple Coneflower) Feb 20 May 15 May 15 Aug 14 – Oct 23 70–90
Foxglove Feb 20 May 15 May 15 Jul 10 – Aug 21 80–120
Gaillardia (Blanket Flower) Mar 6 May 15 May 15 Jul 24 – Oct 30 70–100
Geraniums Feb 13 — May 8 Jul 17 – Sep 25 70–100
Gladiolus — May 8 May 8 Aug 7 – Oct 16 70–100
Hostas Feb 13 — May 15 Aug 14 – Oct 23 60–90
Hyacinths — — — Jul 25 – Aug 15 14–28
Hydrangeas Feb 13 — May 15 Aug 7 – Oct 9 90–150
Impatiens Feb 27 — May 15 Jul 31 – Oct 2 60–75
Irises — — May 15 Jul 10 – Aug 14 60–100
Larkspur — Apr 3 — Jun 12 – Jul 31 60–90
Lilies — — May 15 Aug 7 – Oct 9 70–120
Lobelia Feb 20 — May 1 Jun 26 – Aug 28 70–80
Lupine Feb 20 May 15 May 15 Jul 10 – Aug 21 75–100
Marigolds Mar 20 May 8 May 8 Jul 3 – Sep 18 50–70
Nasturtium Apr 3 May 8 May 8 Jul 3 – Sep 25 55–65
Pansy Feb 13 — May 1 Jun 26 – Aug 14 70–90
Peonies — — May 15 Jul 24 – Aug 28 90–120
Petunia Feb 27 — May 8 Jul 17 – Oct 2 70–90
Phlox Feb 20 May 15 May 15 Aug 7 – Oct 16 80–110
Portulaca Mar 27 May 15 May 15 Jul 3 – Sep 18 50–70
Roses Feb 13 — May 15 Aug 7 – Oct 23 90–180
Salvia Feb 27 — May 8 Jul 17 – Sep 25 70–90
Sedum (Stonecrop) Feb 20 — May 15 Sep 18 – Nov 13 60–90
Snapdragon Feb 20 — May 1 Jul 10 – Sep 4 70–100
Sunflower Apr 10 May 8 May 8 Jul 31 – Oct 2 70–100
Sweet Alyssum Mar 13 Apr 24 May 1 Jun 12 – Aug 14 45–60
Sweet Pea Mar 20 Mar 27 May 1 Jul 24 – Sep 11 65–85
Tulips — — — Jul 18 – Aug 8 15–30
Vinca (Annual) Feb 13 — May 15 Jul 24 – Oct 2 70–90
Yarrow Feb 20 May 1 May 15 Jul 31 – Oct 23 60–90
Zinnia Apr 3 May 8 May 8 Jul 17 – Oct 2 60–70

Recommended for Your Garden

💡
LED Grow Lights $25-60

Full-spectrum LED lights for starting seeds indoors when daylight is limited.

Recommended for cold-climate zones (1-4).

🔥
Seedling Heat Mat $15-35

Warm soil for faster germination of heat-loving crops like tomatoes and peppers.

Recommended for cold-climate zones (1-4).

🪡
Floating Row Covers $12-30

Protect plants from frost, wind, and pests while letting light and water through.

Recommended for cold-climate zones (1-4).

Frequently Asked Questions

What can I grow in Zone 4b?

Zone 4b supports 196 plants in our database including vegetables, herbs, fruits, and flowers. With a 155-day growing season (last frost ~May 1, first frost ~October 3), you can grow most common garden crops with proper timing.

What is Zone 4b?

USDA Zone 4b has an average annual minimum temperature of -25°F to -20°F.

When is the last frost in Zone 4b?

The average last spring frost in Zone 4b is approximately May 1. The first fall frost averages around October 3, giving a growing season of about 155 days. These dates are based on 50% probability — plan for some year-to-year variation.

Composting Guide for Homesteaders

Composting Guide for Homesteaders

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Monthly Planting Guide for Zone 4b

Other Zones

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: August 2026.

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Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.

Plant varieties + growing data

Soil survey + temperature data

Drought monitoring

Household-consumption benchmarks

Derived

Other

Frost dates

Modeling

Precipitation + climate normals

Curated

Pest + disease pressure

Local extension offices

Daylight hours + sun data

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