Greenly Garden
Get the app
EN

When to plant hyacinths in Green Bay: 30 September – 17 November

In Green Bay, hyacinth: plant from 30 September to about 17 November.

Bulbs are best planted early in the window: late-planted bulbs may flower later or less well. Late planting works only while the soil can be dug. Mulch after planting.

The date is about two weeks before the average daily temperature here falls below 0 °C (ten years of weather): an estimate, not the day the ground freezes, and a cold spell can freeze it earlier. Sources: Iowa State University Extension, Wisconsin Horticulture Extension, UNH Extension, RHS, how the ground freezes (NRC Canada, CBD-26).

Hyacinth in Green Bay: soil, season and weather

Nights then average below 0 °C in November–March; the coldest, January, averages -9.8 °C.

Planting30 September – 17 November
First autumn frost30 October
Coldest nightsJanuary, -9.8 °C
Soil back at 1 °C in spring8 March
Daylight11:48 on 30 September
Daylight at the winter solstice8:49

The same dates in Green Bay hold for Garlic, Tulip, Daffodil and Crocus.

Hyacinth in Green Bay: depth, winter cold, pests and pets

Plant hyacinths 10 cm deep, at least 7.5 cm apart (RHS). In the ground hyacinths are fully hardy, but in containers they can be frost tender in cold winters (RHS); here winter nights average below 0 °C, so wrap the pots or move them to a sheltered spot.

In Green Bay the average daily temperature stays at 10 °C or lower for about 27 weeks a year (our estimate from ten years of monthly weather). For this bulb Wisconsin Horticulture Extension gives a cold period of 12–15 weeks at about 2–10 °C. The winter here gives that in the ground, so the bulbs need no pre-chilling.

Flowers get smaller in the years after planting: for full spikes, replace the bulbs or add a few new ones each autumn (RHS).

If squirrels are a problem, protect the bulbs with wire mesh (RHS). Hyacinths are toxic to dogs, cats and horses: intense vomiting and diarrhoea (ASPCA).

Sources: RHS, Wisconsin Horticulture Extension, ASPCA.

Hyacinth in nearby cities

Around Green Bay, Madison is 3 days earlier and Traverse City 10 days later.

CityDistanceDateDifference
Milwaukee165 km2 October – 25 November2 days later
Traverse City192 km10 October – 26 November10 days later
Madison196 km27 September – 20 November3 days earlier
Grand Rapids256 km4 October – 29 November4 days later
Rockford265 km28 September – 25 November2 days earlier
Chicago295 km7 October – 3 December7 days later

Where to buy hyacinth for planting in Green Bay

Planting stock goes into the ground from 30 September to about 17 November; buy it before that. Within 15 km of Green Bay OpenStreetMap lists 6 garden centres, 1 plant nursery and 2 markets (collected 20 October 2026).

Places: © OpenStreetMap contributors, ODbL.

Questions

When to plant hyacinths in Green Bay?

In Green Bay, hyacinth: plant from 30 September to about 17 November. Bulbs are best planted early in the window: late-planted bulbs may flower later or less well. Late planting works only while the soil can be dug. Mulch after planting.

When is the last spring frost in Green Bay?

Last spring frost around 29 April, first autumn frost around 30 October.

Other crops in Green Bay, with their dates