Cornflower · Narva, Ida-Virumaa, Estonia
When to plant cornflowers in Narva
Main outdoor window
29 Apr - 27 May
A climate estimate. Check your soil, forecast and cultivar.
Timed from last spring frost
26 April
In Narva, on your chosen risk.
First flowers
3-23 Jul
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 Narva
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.
Start indoors
15 Mar - 12 Apr
Six weeks before your last frost, under cover or on a windowsill.
Sow direct
29 Apr - 27 May
Delayed by a soil-warming estimate derived from historical air temperatures. The frost-only date would be 5 Apr. Measure your soil before planting.
Plant out
29 Apr - 27 May
Delayed by a soil-warming estimate derived from historical air temperatures. The frost-only date would be 12 Apr. Measure your soil before planting.
In flower
3-23 Jul
Cornflowers through the year
Against the frost risk in Narva
Seasonal context
Rainfall and the growing season in Narva
August has the highest average precipitation (92 mm); March has the lowest (47 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 Narva
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 | -7.8°C (17.9°F)17.9°F (-7.8°C) | -4°C (24.8°F)24.8°F (-4°C) | 29.1 |
| February | -8.5°C (16.8°F)16.8°F (-8.5°C) | -4°C (24.8°F)24.8°F (-4°C) | 26.6 |
| March | -5°C (23°F)23°F (-5°C) | -0.1°C (31.7°F)31.7°F (-0.1°C) | 27.9 |
| April | 0.5°C (32.9°F)32.9°F (0.5°C) | 6.7°C (44°F)44°F (6.7°C) | 12.8 |
| May | 6.1°C (43.1°F)43.1°F (6.1°C) | 13°C (55.4°F)55.4°F (13°C) | 0.8 |
| June | 11.7°C (53°F)53°F (11.7°C) | 17.9°C (64.2°F)64.2°F (17.9°C) | 0.0 |
| July | 15°C (58.9°F)58.9°F (15°C) | 20.8°C (69.4°F)69.4°F (20.8°C) | 0.0 |
| August | 14.2°C (57.6°F)57.6°F (14.2°C) | 20°C (67.9°F)67.9°F (20°C) | 0.0 |
| September | 10°C (50°F)50°F (10°C) | 15.1°C (59.2°F)59.2°F (15.1°C) | 0.0 |
| October | 4.6°C (40.2°F)40.2°F (4.6°C) | 8.2°C (46.7°F)46.7°F (8.2°C) | 3.4 |
| November | -0.4°C (31.2°F)31.2°F (-0.4°C) | 2.3°C (36.1°F)36.1°F (2.3°C) | 15.0 |
| December | -5°C (22.9°F)22.9°F (-5°C) | -1.7°C (28.9°F)28.9°F (-1.7°C) | 25.5 |
For cornflowers, 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 cornflowers for Narva
- August is the wettest month in the rainfall grid, averaging about 92 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 cornflowers
Use the calendar to plan ahead, then check the conditions in your own garden.
- Measure the soil at sowing depth. Aim for at least 7°C (44.6°F); the calendar estimates soil warmth from air temperatures and cannot measure your bed.
- Frost tolerance does not make saturated or frozen soil suitable for planting. Wait until the bed can be worked without smearing or compacting it.
- Harden off plants raised indoors: gradually expose them to outdoor light, wind and temperature before their final move into the bed.
- 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.
Use the cooler season and manage self-seeding
Choose full sun or light shade with drainage. Too much shade can leave stems weak and leaning, while tall varieties may need support.
Avoid unnecessary fertilising: cornflowers tolerate relatively poor soil. Maintain moderate moisture while plants establish rather than leaving a new sowing to dry out.
Deadhead to limit self-seeding, or leave some seed heads where wildlife and natural reseeding are welcome. Check local planting guidance before allowing a non-native plant to spread.
Further reading: NC State Extension Plant Toolbox: cornflower . General crop guidance; local dates on this site are calculated separately. Source checked 18 September 2026 by Safe to Plant; this is not an expert review.
How the dates are calculated and their limits · Keep a growing record · Report a local discrepancy
Why these dates
Choose full sun or light shade with drainage. Too much shade can leave stems weak and leaning, while tall varieties may need support.
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.
This calendar uses frost-relative offsets as a starting point. Cornflowers are timed from 6 weeks before that frost for an indoor start, with planting out 2 weeks before it, and this page simply resolves those offsets against the frost date computed for Narva.
The calendar also applies a soil-warming estimate derived from historical air temperatures. Where that estimate is later than the frost-based date, it delays the window. Soil in your own garden can warm earlier or later; a thermometer at sowing depth is a better final check. Cold, wet conditions can slow germination and increase decay risk.
Narva is zone 6a, 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 186 days, against 65 to 85 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Also in Narva
Other flowers to time
Growing cornflowers in Narva
Can I grow cornflowers in Narva?
The calendar estimates a planting window, not a guarantee of success. August is the wettest month in the rainfall grid, averaging about 92 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 cornflowers in Narva?
Aim for 29 Apr - 27 May in an average year. If you would rather not gamble on the weather, wait until 28 Apr - 26 May - by then frost has finished in nine years out of ten.
Can I plant cornflowers earlier in Narva?
The historical frost estimate is 5 Apr. For Cornflowers, an air-temperature model estimates soil warmth of about 7°C (44.6°F) around 29 Apr. This is not a soil measurement or a forecast. Check your bed at sowing depth; cold, wet conditions can slow growth and increase decay risk.
When might cornflowers flower in Narva?
The estimated period is 3-23 Jul, based on 65 to 85 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 cornflowers 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.