In the garden now (2 November 2026)
Denver planting calendar
Bars show when each crop can go in and when a planting from that window is ready. The blue band is the frost season, from the average first autumn frost to the average last spring frost. Hover or tap a crop for details.
Sow indoorsSow or plant outdoorsHarvestFrost seasonToday
Swipe sideways to see the whole year →
Dates by crop
| Crop | Sow indoors | Sow / plant outdoors | Harvest |
|---|---|---|---|
| Tomato | Mar 26 – Apr 30 | May 21 – Jul 28 plant out | Jul 19 – Oct 7 |
| Pepper | Mar 22 – Apr 26 | May 31 – Jul 24 plant out | Jul 28 – Oct 7 |
| Eggplant (aubergine) | Mar 27 – May 1 | Jun 5 – Jul 21 plant out | Aug 3 – Oct 7 |
| Cucumber | Apr 28 – May 25 | May 26 – Aug 7 sow | Jul 11 – Oct 7 |
| Zucchini (courgette) | Apr 23 – May 20 | May 21 – Aug 11 sow | Jul 5 – Oct 7 |
| Pumpkin and winter squash | Apr 23 – May 20 | May 21 – Jul 10 sow | Aug 9 – Oct 7 |
| Watermelon | May 8 – Jun 4 | Jun 5 – Jul 20 sow | Aug 7 – Oct 7 |
| Sweet corn | – | May 13 – Jul 24 sow | Jul 23 – Oct 7 |
| Green beans | – | May 21 – Aug 7 sow | Jul 9 – Oct 7 |
| Peas | – | Mar 23 – Apr 3 sow | Jun 13 – Jul 12 |
| Lettuce | Mar 2 – Mar 25 | Apr 6 – Apr 22, Aug 18 – Sep 1 sow | Jun 5 – Jul 8, Sep 26 – Oct 18 |
| Spinach | – | Mar 23 – Apr 21 sow | May 29 – Jul 4 |
| Kale | Feb 16 – Mar 23 | Mar 30 – May 14, Aug 8 – Aug 31 sow | Jun 11 – Sep 8, Sep 22 – Nov 22 |
| Cabbage | Jun 20 – Jul 13 | Aug 8 – Aug 17 plant out | Oct 7 – Oct 29 |
| Broccoli | Feb 23 – Mar 18, Jun 30 – Jul 19 | Apr 13 – Apr 22, Aug 18 – Aug 23 plant out | Jun 19 – Jul 19, Oct 12 – Oct 22 |
| Carrots | – | Apr 13 – Jun 30, Aug 8 – Aug 23 sow | Jun 22 – Nov 22 |
| Beets (beetroot) | – | Apr 13 – Jun 30, Aug 8 – Aug 28 sow | Jun 15 – Oct 29 |
| Radishes | – | Mar 30 – May 15, Sep 3 – Sep 19 sow | May 15 – Jun 21, Sep 25 – Oct 22 |
| Onions | Jan 26 – Mar 2 | Apr 6 – Jun 30 plant out | Jul 12 – Oct 8 |
| Garlic | – | Oct 5 – Oct 22 sow | Jun 7 – Jun 27 |
| Potatoes | – | Apr 20 – Jun 17 sow | Jul 13 – Oct 6 |
| Swiss chard | – | Apr 20 – Sep 1 sow | Jun 14 – Oct 29 |
| Basil | Apr 19 – May 17 | May 31 – Aug 25 plant out | Jun 27 – Oct 7 |
| Cilantro (coriander) | – | Apr 13 – May 4, Sep 3 – Sep 10 sow | May 31 – Jul 7, Oct 8 – Oct 22 |
| Parsley | Feb 16 – Mar 23 | Apr 13 – Jun 30, Aug 8 – Aug 19 sow | Jun 26 – Nov 7 |
Dates are for a typical year and the middle of the window is the safest. Sow a little at a time across a window rather than all at once. Cold snaps, heat waves, frost pockets and city warmth all shift the real dates; watch the forecast.
Frost dates in Denver
- Average last spring frost
- May 4
- Late frost (1 year in 10)
- May 16
- Average first autumn frost
- October 8
- Early frost (1 year in 10)
- September 25
- Frost-free growing season
- 156 days
“Average” is the date with an even chance of a later (spring) or earlier (autumn) frost: a night at or below 0 °C (32 °F) at screen height. Tender crops go out a week or two after the spring date, which brings the risk down to about one year in ten.
Source: NOAA 1991–2020 normals, Denver-Stapleton (11 km from the city centre).
Climate at a glance
- Hardiness zone
- 6a from station records
- Average coldest winter night
- -22°C-8°F
- Warmest month
- July, highs 33°C91°F
- Coldest month
- January, lows -7°C20°F
- Crops with an outdoor window
- 25 of 25
The zone follows the USDA scheme: bands of the average lowest temperature of the year, 10 °F wide, split into a and b halves. Worked out from the coldest night of each year 1991–2020 at the NOAA station. It tells you which perennials survive winter, not when to sow.
Temperature and rain by month
Average highAverage lowRainFreezing point
| Month | High | Low | Mean | Rain |
|---|---|---|---|---|
| January | 8°C47°F | -7°C20°F | 1°C33°F | 13 mm0.5 in |
| February | 9°C48°F | -6°C21°F | 2°C35°F | 14 mm0.6 in |
| March | 14°C57°F | -2°C28°F | 6°C43°F | 31 mm1.2 in |
| April | 18°C64°F | 2°C35°F | 10°C49°F | 45 mm1.8 in |
| May | 23°C73°F | 7°C44°F | 15°C59°F | 58 mm2.3 in |
| June | 30°C85°F | 12°C54°F | 21°C69°F | 39 mm1.5 in |
| July | 33°C91°F | 15°C60°F | 24°C75°F | 46 mm1.8 in |
| August | 31°C88°F | 14°C58°F | 23°C73°F | 39 mm1.5 in |
| September | 27°C80°F | 10°C49°F | 18°C65°F | 30 mm1.2 in |
| October | 19°C67°F | 3°C37°F | 11°C52°F | 27 mm1.1 in |
| November | 12°C54°F | -3°C27°F | 5°C41°F | 20 mm0.8 in |
| December | 8°C46°F | -7°C20°F | 1°C33°F | 13 mm0.5 in |
Monthly averages 1991–2020 from TerraClimate (about 4 km grid).