Planting Calendar for ZIP 80302
Based on your local frost dates - last spring frost around May 6, first fall frost around Oct 5 - here is when to plant 79 common crops near ZIP 80302.
Last spring frost
May 6
First fall frost
Oct 5
Hardiness zone
6a
Vegetables
| Crop | Start seeds indoors | Plant outside | Fall planting by |
|---|---|---|---|
| Tomatoes | Mar 25 | May 13 (Transplant out) | - |
| Peppers | Mar 11 | May 20 (Transplant out) | - |
| Cucumbers | Apr 15 | May 13 (Transplant out) | Jul 28 |
| Zucchini | Apr 15 | May 13 (Transplant out) | Aug 2 |
| Summer Squash | Apr 15 | May 13 (Transplant out) | Jul 31 |
| Winter Squash | Apr 15 | May 13 (Transplant out) | - |
| Pumpkins | Apr 15 | May 13 (Transplant out) | - |
| Green Beans | - | May 6 (Direct sow) | Jul 28 |
| Sweet Corn | - | May 13 (Direct sow) | - |
| Melons | Apr 15 | May 20 (Transplant out) | - |
| Watermelon | Apr 15 | May 20 (Transplant out) | - |
| Okra | - | May 20 (Direct sow) | - |
| Eggplant | Mar 11 | May 20 (Transplant out) | - |
| Lettuce | Apr 8 | Apr 8 (Transplant out) | Aug 2 |
| Spinach | - | Mar 25 (Direct sow) | Aug 7 |
| Kale | Mar 25 | Apr 15 (Transplant out) | Jul 28 |
| Peas | - | Mar 25 (Direct sow) | Jul 23 |
| Carrots | - | Apr 15 (Direct sow) | Jul 13 |
| Beets | - | Apr 8 (Direct sow) | Jul 28 |
| Radishes | - | Apr 8 (Direct sow) | Aug 24 |
| Broccoli | Mar 25 | Apr 22 (Transplant out) | Jul 18 |
| Cauliflower | Mar 25 | Apr 22 (Transplant out) | Jul 13 |
| Cabbage | Mar 25 | Apr 15 (Transplant out) | Jul 13 |
| Onions | Feb 25 | Apr 8 (Transplant out) | - |
| Potatoes | - | Apr 22 (Direct sow) | - |
| Swiss Chard | Apr 8 | Apr 22 (Transplant out) | Jul 28 |
| Sweet Potatoes | - | May 27 (Direct sow) | - |
| Brussels Sprouts | Mar 25 | Apr 22 (Transplant out) | Jun 13 |
| Celery | Feb 25 | May 13 (Transplant out) | - |
| Leeks | Feb 25 | Apr 22 (Transplant out) | May 24 |
| Turnips | - | Apr 22 (Direct sow) | Aug 2 |
| Rutabaga | - | May 6 (Direct sow) | Jun 18 |
| Parsnips | - | Apr 22 (Direct sow) | May 24 |
| Kohlrabi | Apr 8 | Apr 22 (Transplant out) | Jul 28 |
| Collard Greens | Mar 25 | Apr 22 (Transplant out) | Jul 18 |
| Mustard Greens | - | Apr 22 (Direct sow) | Aug 7 |
| Arugula | - | Apr 22 (Direct sow) | Aug 12 |
| Bok Choy | Apr 8 | Apr 22 (Transplant out) | Aug 2 |
| Green Onions | - | Apr 22 (Direct sow) | Jul 23 |
| Tomatillos | Mar 25 | May 13 (Transplant out) | - |
| Fennel | Apr 8 | Apr 22 (Transplant out) | Jul 3 |
| Popcorn | May 6 | May 20 (Transplant out) | - |
| Black-Eyed Peas | May 6 | May 20 (Transplant out) | Jul 3 |
| Lima Beans | May 6 | May 20 (Transplant out) | - |
| Edamame | May 6 | May 20 (Transplant out) | - |
| Peanuts | May 6 | May 20 (Transplant out) | - |
| Globe Artichoke | Mar 11 | Apr 22 (Transplant out) | Jun 23 |
| Horseradish | May 6 | Apr 22 (Transplant out) | - |
| Ground Cherries | Mar 25 | May 20 (Transplant out) | - |
| Radicchio | Apr 1 | Apr 22 (Transplant out) | Jul 13 |
| Endive | Apr 1 | Apr 22 (Transplant out) | Jun 23 |
| Watercress | Apr 15 | Apr 22 (Transplant out) | Jul 23 |
| Sorrel | Mar 25 | Apr 15 (Transplant out) | Jul 23 |
| Sunchokes | May 6 | Apr 22 (Transplant out) | - |
| Malabar Spinach | Mar 25 | May 20 (Transplant out) | - |
| Amaranth Greens | Apr 15 | May 20 (Transplant out) | Aug 7 |
| Luffa Gourd | Mar 25 | May 20 (Transplant out) | - |
| New Zealand Spinach | Apr 8 | May 20 (Transplant out) | - |
| Fava Beans | May 6 | Apr 8 (Transplant out) | Jun 28 |
| Chayote | Apr 8 | May 20 (Transplant out) | - |
| Corn Salad | May 6 | Apr 8 (Transplant out) | Jul 23 |
| Bitter Melon | Apr 8 | May 20 (Transplant out) | - |
| Cardoon | Mar 25 | May 6 (Transplant out) | - |
Herbs
| Crop | Start seeds indoors | Plant outside | Fall planting by |
|---|---|---|---|
| Basil | Mar 25 | May 13 (Transplant out) | - |
| Cilantro | - | Apr 22 (Direct sow) | Aug 2 |
| Parsley | Mar 11 | May 20 (Transplant out) | Jul 8 |
| Dill | - | May 13 (Direct sow) | Jul 23 |
| Lemon Balm | Mar 25 | May 6 (Transplant out) | - |
| Borage | May 6 | May 6 (Transplant out) | Jul 28 |
| Chervil | May 6 | Apr 15 (Transplant out) | Jul 28 |
| Lemongrass | Mar 11 | May 20 (Transplant out) | - |
| Summer Savory | Mar 25 | May 6 (Transplant out) | - |
| Marjoram | Mar 25 | May 13 (Transplant out) | - |
| Lovage | Mar 25 | May 6 (Transplant out) | Jun 23 |
| Anise Hyssop | Mar 11 | May 6 (Transplant out) | - |
| Shiso | Mar 25 | May 13 (Transplant out) | - |
| Stevia | Mar 11 | May 20 (Transplant out) | - |
| Chamomile | Mar 25 | Apr 22 (Transplant out) | Jul 18 |
| Tarragon | May 6 | May 6 (Transplant out) | - |
How to read this calendar
Start seeds indoors is when to sow in trays inside so seedlings are ready to transplant. Plant outside is when to transplant seedlings or direct-sow seed, based on frost tolerance. Fall planting by is the latest date to start a fall crop and still harvest before the first fall frost. Tender crops wait until after the last spring frost; hardy crops can go out earlier.
Computed from NOAA 1991–2020 Climate Normals at Boulder, Co, 4.9 miles away. Averages for planning, not a forecast. Page updated Aug 4, 2026.