Crocus · Des Plaines, Illinois, United States
When to plant crocuses in Des Plaines
Main outdoor window
10-24 Sep
A climate estimate. Check your soil, forecast and cultivar.
Timed from last spring frost
26 April
In Des Plaines, on your chosen risk.
First flowers
1 Feb - 31 Mar
If you plant at the start of the window.
The average last frost. Half of all years are later than this.
Step by step in Des Plaines
Download these planting dates (.ics)
Import into Apple Calendar, Google Calendar or Outlook. Dates use the selected risk level and are planning estimates, not frost alerts.
Each window is a planning range. Check the forecast, soil and cultivar before planting; a later date is not automatically safer in hot or wet conditions.
Plant the corms
10-24 Sep
Four to six weeks before your first frost, so roots form before the ground cools.
In flower
1 Feb - 31 Mar
Crocuses through the year
Against the frost risk in Des Plaines
Seasonal context
Rainfall and the growing season in Des Plaines
May has the highest average precipitation (121 mm); January has the lowest (44 mm). Compare this pattern with the planting windows and your water supply.
During wetter months, check that beds and containers drain after heavy rain. During drier months, plan how you will keep seeds and new transplants watered. Monthly averages can hide long dry spells and intense storms; they do not show soil moisture, humidity or this week's weather.
Source: NASA POWER, corrected MERRA-2 precipitation, 2001–2020. Values are approximate monthly totals, including the water equivalent of snow, from the nearest 0.5° × 0.625° grid cell. This reference period differs from the temperature record. Rainfall provides context and does not change the calculated planting dates. Method and limitations.
Monthly growing conditions in Des Plaines
Compare the planting window with the local temperature pattern. These are historical monthly averages, not this year's forecast or measured soil temperatures. Average frost days do not tell you whether a particular night will freeze.
| Month | Average low | Average high | Frost days |
|---|---|---|---|
| January | -9.8°C (14.4°F)14.4°F (-9.8°C) | -1.5°C (29.3°F)29.3°F (-1.5°C) | 29.4 |
| February | -8.2°C (17.3°F)17.3°F (-8.2°C) | 1.1°C (33.9°F)33.9°F (1.1°C) | 26.6 |
| March | -2.4°C (27.6°F)27.6°F (-2.4°C) | 7.7°C (45.9°F)45.9°F (7.7°C) | 23.1 |
| April | 2.6°C (36.7°F)36.7°F (2.6°C) | 14.5°C (58.1°F)58.1°F (14.5°C) | 8.7 |
| May | 8.8°C (47.8°F)47.8°F (8.8°C) | 20.7°C (69.3°F)69.3°F (20.7°C) | 0.3 |
| June | 14.7°C (58.5°F)58.5°F (14.7°C) | 26.3°C (79.3°F)79.3°F (26.3°C) | 0.0 |
| July | 17.6°C (63.8°F)63.8°F (17.6°C) | 28.7°C (83.6°F)83.6°F (28.7°C) | 0.0 |
| August | 17.2°C (63°F)63°F (17.2°C) | 28.3°C (83°F)83°F (28.3°C) | 0.0 |
| September | 12.9°C (55.2°F)55.2°F (12.9°C) | 24.7°C (76.4°F)76.4°F (24.7°C) | 0.0 |
| October | 5.9°C (42.7°F)42.7°F (5.9°C) | 17°C (62.6°F)62.6°F (17°C) | 3.2 |
| November | -0.7°C (30.7°F)30.7°F (-0.7°C) | 8.4°C (47.2°F)47.2°F (8.4°C) | 18.0 |
| December | -6.3°C (20.6°F)20.6°F (-6.3°C) | 1.4°C (34.5°F)34.5°F (1.4°C) | 27.5 |
For crocuses, also check drainage, sunlight and cultivar requirements. See the rainfall context above; humidity, irrigation and local pest pressure are not calculated.
Local growing check
Before choosing crocuses for Des Plaines
- May is the wettest month in the rainfall grid, averaging about 121 mm. Check how your own bed drains and plan watering around actual soil moisture; monthly rain totals are not an irrigation schedule.
The temperature and rainfall tables on this page show the underlying climate estimates. How these suitability checks work · Record what happens in your garden.
Before you plant crocuses
Use the calendar to plan ahead, then check the conditions in your own garden.
- Frost tolerance does not make saturated or frozen soil suitable for planting. Wait until the bed can be worked without smearing or compacting it.
- Use the maturity range on your seed packet when choosing a variety. Cold, short days and transplant stress can make harvest later than the calendar estimate.
Plan a spring crocus patch that can finish its leaf growth
Provide sun or light shade and sharp drainage. Keep moisture available during active growth, while avoiding heavy waterlogged soil. Newly planted corms may need protection from digging rodents without using traps or barriers that injure wildlife.
Mark the area during dormancy and divide congested patches when appropriate. Do not confuse ornamental spring crocus with saffron or with poisonous Colchicum sold as autumn crocus. A common name alone is not an edible-plant identification.
What to record this season
Did corms remain in place and return with flowers after their leaves completed growth? Add the cultivar, sowing date and conditions to your growing record so you can compare next season.
Further reading: Crocus (Common Crocus, Dutch Crocus, Dutch Crows, Species Crocuses) | North Carolina Extension Gardener Plant Toolbox . General crop guidance; local dates on this site are calculated separately. Source checked 19 September 2026 by Safe to Plant; this is not an expert review.
The reference describes plant identity and cultivation. Its regional calendar months and hardiness observations do not validate the calculated dates for another location. This reference covers the broader plant group; confirm the named form and its specific requirements with the supplier.
How the dates are calculated and their limits · Keep a growing record · Report a local discrepancy
Why these dates
Provide sun or light shade and sharp drainage. Keep moisture available during active growth, while avoiding heavy waterlogged soil. Newly planted corms may need protection from digging rodents without using traps or barriers that injure wildlife.
Check the named variety and local forecast before exposing young growth. The catalog cold-damage figure is a reference, not a guarantee: plant age, acclimatisation, wind and the duration of a freeze affect damage.
Crocuses are anchored to the first autumn frost rather than the last spring one, so the planting window on this page counts backwards from the end of the season in Des Plaines instead of forwards from its start.
Des Plaines is zone 5b, within the crop's general range. This is an initial cold-hardiness check; cultivar, exposure, drainage and unusual winters can still change the outcome.
The median frost-free season here is 179 days, against 120 to 170 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Nearby
Crocuses in places close by
Also in Des Plaines
Other flowers to time
Growing crocuses in Des Plaines
Can I grow crocuses in Des Plaines?
The calendar estimates a planting window, not a guarantee of success. May is the wettest month in the rainfall grid, averaging about 121 mm. Check how your own bed drains and plan watering around actual soil moisture; monthly rain totals are not an irrigation schedule.
When should I plant crocuses in Des Plaines?
Aim for 10-24 Sep in an average year. If you would rather not gamble on the weather, wait until 27 Aug - 10 Sep - by then frost has finished in nine years out of ten.
When might crocuses flower in Des Plaines?
The estimated period is 1 Feb - 31 Mar, based on 120 to 170 days from the modeled planting date. Cultivar, planting material and growing conditions can change this interval; check the plant as well as the calendar.
How much frost will crocuses tolerate?
Check the named variety and local forecast before exposing young growth. The catalog cold-damage figure is a reference, not a guarantee: plant age, acclimatisation, wind and the duration of a freeze affect damage.