When to plant crocuses in Grenoble: 25 September – 1 December

In Grenoble, crocus: plant from 25 September to about 1 December. For planting stock, the places nearby include Ferme de la Grand'Mèche (farm shop, 14 km) and Chèvrerie du Pic St Michel (farm shop, 15 km); addresses and opening hours are below.

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).

Crocus in Grenoble: soil, season and weather

Nights then average below 0 °C in November–March; the coldest, January, averages -5.1 °C.

Planting	25 September – 1 December
First autumn frost	25 October
Coldest nights	January, -5.1 °C
Soil back at 1 °C in spring	19 February
Daylight	12:04 on 25 September
Daylight at the winter solstice	8:45

The same dates in Grenoble hold for Garlic, Tulip, Daffodil and Hyacinth.

Crocus in Grenoble: depth, winter cold, pests and pets

Plant Dutch crocuses (Crocus vernus) about 12 cm deep and 9 cm apart; smaller species go 7–10 cm deep (RHS).

In Grenoble the average daily temperature stays at 10 °C or lower for about 31 weeks a year (our estimate from ten years of monthly weather). For this bulb Wisconsin Horticulture Extension gives a cold period of 15–17 weeks at about 2–10 °C. The winter here gives that in the ground, so the bulbs need no pre-chilling.

Crocuses multiply on their own (they naturalise); in a lawn, hold off mowing until their leaves die back (RHS).

Birds, squirrels and rodents damage crocuses; planting under metal mesh may reduce losses (RHS). Spring crocus gives dogs and cats vomiting and diarrhoea; do not confuse it with autumn crocus (Colchicum), which is very toxic (Pet Poison Helpline).

Sources: RHS, Wisconsin Horticulture Extension, Pet Poison Helpline.

Crocus in nearby cities

Around Grenoble, Aosta is 45 days earlier and Lyon 31 days later.

City	Distance	Date	Difference
Valence	70 km	22 October – end of December	27 days later
Annecy	86 km	15 October – end of December	20 days later
Lyon	93 km	26 October – end of December	31 days later
Saint-Étienne	108 km	18 October – end of December	23 days later
Geneva	117 km	18 October – end of December	23 days later
Aosta	139 km	11 August – 22 October	45 days earlier

Where to buy crocus for planting in Grenoble

Planting stock goes into the ground from 25 September to about 1 December; buy it before that. Within 15 km of Grenoble OpenStreetMap lists 17 garden centres, 4 plant nurseries, 55 markets and 19 farm shops (collected 20 October 2026).

Ferme de la Grand'Mèche — farm shop
Mon, Tue, Thu, Fri 17:00–19:00; Wed, Sat 11:00–12:00, 17:00–19:00; Sun 17:00–18:00 · 14 km
Chèvrerie du Pic St Michel — farm shop
Mon–Fri 09:00–12:00, 17:00–19:00; Sat 17:00–19:00 · 15 km
Gamm Vert — garden centre
15 km
Ets Coquet — garden centre
5 km
Jardins Alternatifs — garden centre
8 km
Des Racines et des Fruits — plant nursery
12 km · racinesetfruits.fr
Jardin ingeco — plant nursery
4 km
Palmeraie des Alpes — plant nursery
13 km

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