ZonePlant

Local planting guide · Midwest

Green Bay, WI

zip 54306

Green Bay is in USDA hardiness zone 5b, with average winter lows of -15°F to -10°F. The local growing season runs roughly 04/30 through 10/09 (~161 days). This zip falls within the Midwest growing region.

USDA zone
5b -15°F to -10°F
Last spring frost
04/30
First fall frost
10/09
Growing season
161 days
Compatible crops
81
Growing region
Midwest

Right now in Green Bay

Week 18 priorities

On the docket: transplant out after last frost · direct sow after last frost. See the full calendar →

Gardening in Green Bay

Green Bay gardening is shaped by a short, intense growing season and extreme winter cold. The 161-day frost-free window, from an April 30 last spring frost to October 9 first fall frost, is one of the shorter growing seasons in zone 5b, which fundamentally drives crop and variety selection. Winter temperatures regularly drop to -15 to -10°F, cold enough to reliably grow apples, pears, and cold-hardy sour cherries, but too severe for most peach cultivars. Late spring frosts pose the dominant challenge; warm spells in late April trigger growth and flowers, and a May cold snap kills them before they fruit. The short growing season also means summer heat is never limiting here, unlike warmer zones. Instead, the primary constraint is accumulating enough warm days to ripen fruit before the October 9 first frost. This shifts variety selection sharply toward short-season, cold-hardy types and away from late-ripening cultivars that work in zone 5a or warmer. Gardeners in Green Bay benefit most by focusing on what the climate does well, hardy stone fruits and apples bred for cold, rather than stretching for marginal crops.

Regional context · Midwest

What the Midwest brings to Green Bay

Continental humid. Cold winters, hot humid summers. Heart of the country's vegetable, sweet corn, and cool-climate fruit production. Michigan and Wisconsin are major fruit states.

Full Midwest guide →

Common challenges

Issues that most often defeat home gardeners in zone 5b, drawn from the broader USDA zone profile.

  • Plum curculio
  • Codling moth
  • Cedar-apple rust

What defeats new gardeners in Green Bay

Green Bay's main challenges are late spring frosts, a truncated growing season, and persistent humidity that encourages fungal disease. Warm spells in late April often trigger growth and flowering on apples, cherries, and pears, but a hard May frost kills open flower buds, eliminating that year's crop. This variability makes spring planning difficult. The October 9 first frost date leaves little margin for error; many cultivars marketed for longer zone 5a seasons must be harvested early or are lost to freeze damage. Summer humidity, amplified by proximity to Lake Michigan, strongly favors fungal diseases, apple scab, cherry leaf spot, and powdery mildew are endemic issues. These diseases persist from year to year in fallen leaves and pruning debris. The combination of humidity and extreme winter cold makes preventive disease management non-negotiable for any success with tree fruits.

Crops that grow in Green Bay

81 crops from our catalog match zone 5b, grouped by type.

Tree fruit

11 crops

See all 11 tree fruit for zone 5b →

Berries

20 crops

See all 20 berries for zone 5b →

Nuts

4 crops

Vegetables

37 crops

See all 37 vegetables for zone 5b →

Herbs

9 crops

See all 9 herbs for zone 5b →

Plan the year

Planting calendar for Green Bay

Year-view of seed starting, transplanting, planting, pruning, fertilizing, harvest, and pest-watch windows tuned to Green Bay's local frost dates.

Week ? · loading

This week in Green Bay, WI (zone 5b)

Quiet week in Green Bay, WI (zone 5b). this week is a good time to step back and plan ahead.

Nothing critical on the calendar this week.

404 bars · 81 crops

Filter

Calendar logic combines NOAA frost normals with crop-specific timing data. Local microclimate and weather always overrules the calendar; use this as a starting point.

Top pests for zone 5b

Ranked by how many crops in your zone they affect. Click through for IPM controls and signs to watch for.

Mule Deer (Odocoileus hemionus) sniff (deer-damage)
Deer Browse 30 crops

Odocoileus species

Whitetail and mule deer browse can devastate orchards and gardens, particularly in winter when food is scarce. Antler rub on young trunks kills saplings outright.

Blattlaeuse-JR-T3-I176-2024-09-22 (aphid)
Aphid 28 crops

Multiple species (Aphididae)

Small soft-bodied sap-sucking insects that reproduce explosively in spring. Excrete honeydew that supports sooty mold and attracts ants. Transmit viral diseases.

Multiple Plant Species- microhabitats (bird-damage)
Bird Damage 23 crops

Multiple species

Robins, catbirds, mockingbirds, starlings, cedar waxwings and other songbirds can strip ripening berry and fruit crops in days. Crows and blackbirds also damage fresh sweet corn ears in milk stage. The single biggest yield-loss factor in unprotected home plantings.

Sylvilagus palustris in Sanibel Island 02 (rabbit-damage)
Rabbit Damage 22 crops

Sylvilagus and Lepus species

Cottontails and jackrabbits strip bark from young fruit trees in winter and graze tender garden vegetables year-round, especially seedlings.

Tetranychus urticae on sweet pepper, Bonenspintmijt op paprika (2) (two-spotted-spider-mite)
Two-Spotted Spider Mite 16 crops

Tetranychus urticae

Tiny mite that feeds on leaf undersides, causing stippling and webbing during hot dry weather.

Lochmaea (10.3897-zookeys.856.30838) Figure 10 (flea-beetle)
Flea Beetle 16 crops

Multiple species (Chrysomelidae)

Tiny black or bronze jumping beetles that put hundreds of small holes in seedling leaves. Most damaging on direct-seeded brassicas and young eggplant.

Popillia japonica (japanese-beetle)
Japanese Beetle 15 crops

Popillia japonica

Defoliating beetle introduced to North America in 1916. Skeletonizes leaves of many fruit trees, berry canes, and pecan.

Drosophila suzukii smulans2 (spotted-wing-drosophila)
Spotted Wing Drosophila 15 crops

Drosophila suzukii

Invasive vinegar fly that attacks ripening soft fruit, unlike native Drosophila species which target overripe fruit. Now the dominant berry-and-cherry pest across the US.

All pests →

Top diseases for zone 5b

Ranked by how many crops in your zone they affect. Click through for symptoms, controls, and resistant varieties.

Gray mold (Botrytis cinerea) on Rosa sp-5573591 (gray-mold)
Gray Mold (Botrytis) fungal

Botrytis cinerea

Ubiquitous fungal disease that causes fruit rot during cool wet weather, often the dominant berry disease in humid regions.

Downy mildew on leaves of Cucumis sativus (downy-mildew-cucurbit)
Downy Mildew fungal

Pseudoperonospora cubensis (cucurbits) and others

Water mold (oomycete, not a true fungus) that thrives in cool damp conditions. Spreads rapidly through cucurbit and brassica plantings on wind-borne spores.

Seedlings - Flickr - peganum (3) (damping-off)
Damping Off fungal

Pythium and Rhizoctonia species

Soil-borne complex of water molds and fungi that kill seedlings before or shortly after emergence. The single most common cause of seed-starting failures.

Tobacco mosaic virus symptoms tobacco (mosaic-virus)
Mosaic Virus viral

Cucumber mosaic virus, Tobacco mosaic virus, and others

Family of plant viruses producing mottled yellow-and-green leaf patterns. Vectored primarily by aphids; some are seed-transmitted or spread by handling tools and tobacco products.

Crown Gall of Sunflower (crown-gall)
Crown Gall bacterial

Agrobacterium tumefaciens

Soil-borne bacterium that enters plants through wounds and induces tumor-like galls on roots, crown, and lower stems. Galls reduce vigor and shorten plant lifespan; on Rubus the disease is often fatal.

Plasmodiophora brassicae on cauliflower, Knolvoet bij bloemkool (clubroot)
Clubroot fungal

Plasmodiophora brassicae

Soil-borne disease causing characteristic distorted club-shaped roots on brassicas. Persists in soil for 10-20 years; the dominant brassica pathogen in acidic poorly-drained soils.

Elsinoë veneta a1 (8) (anthracnose-cane)
Cane Anthracnose fungal

Elsinoe veneta

Fungal cane disease causing purple-bordered lesions that girdle and weaken bramble and Ribes canes, reducing yield over consecutive seasons.

Ligustrum lucidum IMG 2904 (phytophthora-root-rot)
Phytophthora Root Rot fungal

Phytophthora species

Soil-borne water mold that destroys roots in waterlogged soils, the leading cause of blueberry decline in poorly drained sites.

All diseases →

Companion planting suggestions

Beneficial pairings drawn from companion data, filtered to crops that grow in zone 5b.

All companion pairs →

Soil types reference

Soil texture and pH decide what grows easily on your specific lot. Find the closest match below for crop recommendations and amendment guidance.

Practical tips for Green Bay

Delay spring plantings until May 15 rather than the conventional May 1 weekend. The April 30 average last frost date masks significant year-to-year variation; tender annual crops and perennials are safer planted after mid-May.

Choose short-season apple and cherry varieties. With 161 frost-free days, select apples and cherries that ripen by mid-September, leaving buffer before the October 9 first frost. When available, choose cultivars originally bred for Zone 4 (like Zestar, Gala, or Honeycrisp) rather than zone 5, as they have later bloom times and better tolerate April frost surprises.

Mulch deeply in November. Winter lows of -10 to -15°F and freeze-thaw cycles in early spring can heave perennials. Apply 4 to 6 inches of wood chips or leaf mulch after the ground freezes to stabilize soil temperature and reduce winter injury.

Frequently asked questions

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What's the best fruit tree to plant in Green Bay?

Sour cherries and apples are most reliable; European plums and pears follow. Peaches are marginal, the -10 to -15°F winters and late spring frosts often kill flower buds. Choose apple varieties originally bred for Zone 4 (Zestar, Gala, Honeycrisp) rather than heat-demanding types.

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When should I transplant tomatoes outdoors?

Transplant after May 20-25 to avoid late-frost risk. The April 30 average last frost is deceptive; frost damage to tender plants commonly occurs into May. Start seeds indoors in late March for a mature plant by transplant time.

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What's the biggest weather risk in zone 5b here?

Late spring frosts are most damaging. Warm spells in late April trigger growth and flowers, then a hard May freeze kills them. Protect by choosing late-blooming varieties, avoiding frost pockets, and ensuring morning sun exposure to help thaw frost damage.

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How do I manage apple scab and fungal diseases?

Lake Michigan humidity drives apple scab, cherry leaf spot, and powdery mildew. Manage by pruning for air circulation, removing fallen leaves (fungal spore source), and applying sulfur or neem preventively when cool and wet. Resistant varieties help but don't eliminate management needs.

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Can I grow Japanese plums in Green Bay?

Japanese plums are risky; they bloom very early and face late-frost damage regularly. European plums (like 'Stanley') need fewer chill hours and bloom later, making them far safer. Attempt Japanese types only with a protected south-facing microclimate.

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What should I plant in early spring?

Start cool-season crops (peas, leafy greens, broccoli, cabbage) in late April as soon as soil is workable; they tolerate light frosts and mature well before summer. Delay warm-season crops (tomatoes, beans, squash, peppers) until after May 20 to avoid frost loss.

Frost data: NOAA Climate Normals 1991-2020, station USW00014898. Local microclimates can shift these dates by a week or more.

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