Harman US

Planting Calendar for ZIP 80731

Based on your local frost dates - last spring frost around May 11, first fall frost around Oct 3 - here is when to plant 79 common crops near ZIP 80731.

Last spring frost
May 11
First fall frost
Oct 3
Hardiness zone
5b

Vegetables

Crop Start seeds indoors Plant outside Fall planting by
Tomatoes Mar 30 May 18 (Transplant out) -
Peppers Mar 16 May 25 (Transplant out) -
Cucumbers Apr 20 May 18 (Transplant out) Jul 26
Zucchini Apr 20 May 18 (Transplant out) Jul 31
Summer Squash Apr 20 May 18 (Transplant out) Jul 29
Winter Squash Apr 20 May 18 (Transplant out) -
Pumpkins Apr 20 May 18 (Transplant out) -
Green Beans - May 11 (Direct sow) Jul 26
Sweet Corn - May 18 (Direct sow) -
Melons Apr 20 May 25 (Transplant out) -
Watermelon Apr 20 May 25 (Transplant out) -
Okra - May 25 (Direct sow) -
Eggplant Mar 16 May 25 (Transplant out) -
Lettuce Apr 13 Apr 13 (Transplant out) Jul 31
Spinach - Mar 30 (Direct sow) Aug 5
Kale Mar 30 Apr 20 (Transplant out) Jul 26
Peas - Mar 30 (Direct sow) Jul 21
Carrots - Apr 20 (Direct sow) Jul 11
Beets - Apr 13 (Direct sow) Jul 26
Radishes - Apr 13 (Direct sow) Aug 22
Broccoli Mar 30 Apr 27 (Transplant out) Jul 16
Cauliflower Mar 30 Apr 27 (Transplant out) Jul 11
Cabbage Mar 30 Apr 20 (Transplant out) Jul 11
Onions Mar 2 Apr 13 (Transplant out) -
Potatoes - Apr 27 (Direct sow) -
Swiss Chard Apr 13 Apr 27 (Transplant out) Jul 26
Sweet Potatoes - Jun 1 (Direct sow) -
Brussels Sprouts Mar 30 Apr 27 (Transplant out) Jun 11
Celery Mar 2 May 18 (Transplant out) -
Leeks Mar 2 Apr 27 (Transplant out) May 22
Turnips - Apr 27 (Direct sow) Jul 31
Rutabaga - May 11 (Direct sow) Jun 16
Parsnips - Apr 27 (Direct sow) May 22
Kohlrabi Apr 13 Apr 27 (Transplant out) Jul 26
Collard Greens Mar 30 Apr 27 (Transplant out) Jul 16
Mustard Greens - Apr 27 (Direct sow) Aug 5
Arugula - Apr 27 (Direct sow) Aug 10
Bok Choy Apr 13 Apr 27 (Transplant out) Jul 31
Green Onions - Apr 27 (Direct sow) Jul 21
Tomatillos Mar 30 May 18 (Transplant out) -
Fennel Apr 13 Apr 27 (Transplant out) Jul 1
Popcorn May 11 May 25 (Transplant out) -
Black-Eyed Peas May 11 May 25 (Transplant out) Jul 1
Lima Beans May 11 May 25 (Transplant out) -
Edamame May 11 May 25 (Transplant out) -
Peanuts May 11 May 25 (Transplant out) -
Globe Artichoke Mar 16 Apr 27 (Transplant out) Jun 21
Horseradish May 11 Apr 27 (Transplant out) -
Ground Cherries Mar 30 May 25 (Transplant out) -
Radicchio Apr 6 Apr 27 (Transplant out) Jul 11
Endive Apr 6 Apr 27 (Transplant out) Jun 21
Watercress Apr 20 Apr 27 (Transplant out) Jul 21
Sorrel Mar 30 Apr 20 (Transplant out) Jul 21
Sunchokes May 11 Apr 27 (Transplant out) -
Malabar Spinach Mar 30 May 25 (Transplant out) -
Amaranth Greens Apr 20 May 25 (Transplant out) Aug 5
Luffa Gourd Mar 30 May 25 (Transplant out) -
New Zealand Spinach Apr 13 May 25 (Transplant out) -
Fava Beans May 11 Apr 13 (Transplant out) Jun 26
Chayote Apr 13 May 25 (Transplant out) -
Corn Salad May 11 Apr 13 (Transplant out) Jul 21
Bitter Melon Apr 13 May 25 (Transplant out) -
Cardoon Mar 30 May 11 (Transplant out) -

Herbs

Crop Start seeds indoors Plant outside Fall planting by
Basil Mar 30 May 18 (Transplant out) -
Cilantro - Apr 27 (Direct sow) Jul 31
Parsley Mar 16 May 25 (Transplant out) Jul 6
Dill - May 18 (Direct sow) Jul 21
Lemon Balm Mar 30 May 11 (Transplant out) -
Borage May 11 May 11 (Transplant out) Jul 26
Chervil May 11 Apr 20 (Transplant out) Jul 26
Lemongrass Mar 16 May 25 (Transplant out) -
Summer Savory Mar 30 May 11 (Transplant out) -
Marjoram Mar 30 May 18 (Transplant out) -
Lovage Mar 30 May 11 (Transplant out) Jun 21
Anise Hyssop Mar 16 May 11 (Transplant out) -
Shiso Mar 30 May 18 (Transplant out) -
Stevia Mar 16 May 25 (Transplant out) -
Chamomile Mar 30 Apr 27 (Transplant out) Jul 16
Tarragon May 11 May 11 (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 Holyoke, Co, 13.8 miles away. Averages for planning, not a forecast. Page updated Aug 4, 2026.

Full frost dates for 80731 Local weather →