Sunflower · Gary, Indiana, United States
When to plant sunflowers in Gary
Main outdoor window
29 Apr - 13 May
A climate estimate. Check your soil, forecast and cultivar.
Timed from last spring frost
22 April
In Gary, on your chosen risk.
First flowers
8 Jul - 7 Aug
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 Gary
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.
Sow direct
29 Apr - 13 May
One week after your last frost.
In flower
8 Jul - 7 Aug
Sunflowers through the year
Against the frost risk in Gary
Seasonal context
Rainfall and the growing season in Gary
May has the highest average precipitation (114 mm); January has the lowest (51 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 Gary
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) | -0.4°C (31.3°F)31.3°F (-0.4°C) | 28.4 |
| February | -6.5°C (20.3°F)20.3°F (-6.5°C) | 2.1°C (35.7°F)35.7°F (2.1°C) | 25.9 |
| March | -1.6°C (29.1°F)29.1°F (-1.6°C) | 8.2°C (46.7°F)46.7°F (8.2°C) | 21.5 |
| April | 3.4°C (38.2°F)38.2°F (3.4°C) | 14.6°C (58.3°F)58.3°F (14.6°C) | 6.7 |
| May | 9.4°C (48.9°F)48.9°F (9.4°C) | 20.4°C (68.8°F)68.8°F (20.4°C) | 0.2 |
| June | 15.2°C (59.4°F)59.4°F (15.2°C) | 25.7°C (78.2°F)78.2°F (25.7°C) | 0.0 |
| July | 18.1°C (64.6°F)64.6°F (18.1°C) | 28.1°C (82.6°F)82.6°F (28.1°C) | 0.0 |
| August | 17.8°C (64°F)64°F (17.8°C) | 28°C (82.3°F)82.3°F (28°C) | 0.0 |
| September | 13.7°C (56.6°F)56.6°F (13.7°C) | 24.7°C (76.5°F)76.5°F (24.7°C) | 0.0 |
| October | 7°C (44.6°F)44.6°F (7°C) | 17.5°C (63.4°F)63.4°F (17.5°C) | 1.4 |
| November | 0.5°C (32.8°F)32.8°F (0.5°C) | 9.2°C (48.6°F)48.6°F (9.2°C) | 14.8 |
| December | -4.7°C (23.6°F)23.6°F (-4.7°C) | 2.5°C (36.5°F)36.5°F (2.5°C) | 25.9 |
For sunflowers, 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 sunflowers for Gary
- May is the wettest month in the rainfall grid, averaging about 114 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 sunflowers
Use the calendar to plan ahead, then check the conditions in your own garden.
- Measure the soil at sowing depth. Aim for at least 12°C (53.6°F); the calendar estimates soil warmth from air temperatures and cannot measure your bed.
- Check the local overnight forecast before planting out. Delay planting or keep protection ready if frost is forecast, even after the historical last-frost date.
- 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.
Choose a sunflower for your space
Mature heights range from compact plants to giants. Check the packet before placing them near paths, smaller crops or an exposed boundary.
Keep seedlings watered while roots establish. Established plants can tolerate dry conditions better than newly germinated seeds, so drought tolerance is not a reason to leave the seedbed dry.
If you want wildlife value, leave suitable seedheads for birds. If you want cut flowers or edible seed, choose a variety intended for that purpose.
Growing in a container
Choose a dwarf variety for pots and provide drainage; large varieties need considerably more root room and protection from wind.
Further reading: NC State Extension: annual sunflower . 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
Mature heights range from compact plants to giants. Check the packet before placing them near paths, smaller crops or an exposed boundary.
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. Sunflowers are timed for direct sowing 1 weeks after it, and this page simply resolves those offsets against the frost date computed for Gary.
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.
The median frost-free season here is 192 days, against 70 to 100 days to first flower for this crop counted from sowing. That margin is what decides whether a late sowing is worth attempting.
Growing sunflowers in Gary
Can I grow sunflowers in Gary?
The calendar estimates a planting window, not a guarantee of success. May is the wettest month in the rainfall grid, averaging about 114 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 sunflowers in Gary?
Aim for 29 Apr - 13 May in an average year. If you would rather not gamble on the weather, wait until 12-26 May - by then frost has finished in nine years out of ten.
When might sunflowers flower in Gary?
The estimated period is 8 Jul - 7 Aug, based on 70 to 100 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 sunflowers 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.