Castle Rock, Colorado planting calendar and frost dates

Frost dates in Castle Rock

NOAA U.S. Climate Normals 1991-2020 for Elizabeth 2nw, 11.5 miles ENE of the city center and 290 feet lower. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.

What to plant each month in Castle Rock

1. January

   Start indoors: onions

2. February

   Start indoors: broccoli, cauliflower, collard greens, kale, leeks, onions, petunias, ranunculus

3. March

   Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, celery, chives, collard greens, eggplants, ginger, kale, leeks, lettuce, marigolds, onions, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons

4. April

   Start indoors: basil, black-eyed susans, cabbages, cantaloupes, celery, chives, cilantro, collard greens, eggplants, ginger, lettuce, marigolds, nasturtiums, peppers, ranunculus, sage, snapdragons, spinach, swiss chard, tomatoes, watermelons

   Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, lettuce, onions, parsley, peas, poppies, radishes, ranunculus, raspberries, rhubarb, roses, spinach, strawberries, swiss chard, turnips, wildflowers

5. May

   Start indoors: cantaloupes, cosmos, cucumbers, okra, pumpkins, ranunculus, watermelons, winter squash, zucchini

   Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, dahlias, dill, figs, garden mums, ginger, gladioli, grapes, green onions, kentucky bluegrass, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, onions, oregano, parsley, perennial ryegrass, petunias, potatoes, radishes, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, turnips

6. June

   Start indoors: zinnias

   Plant or sow outdoors: asparagus, basil, bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, garden mums, ginger, green beans, green onions, kentucky bluegrass, okra, peanuts, peppers, perennial ryegrass, pumpkins, st. augustinegrass, sunflowers, sweet peas, sweet potatoes, tall fescue, tomatoes, watermelons, winter squash, zoysiagrass, zucchini

   Plant for fall: brussels sprouts

7. July

   Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, zinnias, zoysiagrass

   Plant for fall: bearded irises, beets, broccoli, brussels sprouts, cabbages, carrots, cauliflower, collard greens, daylilies, kale, lettuce, peas, radishes, snapdragons, spinach, swiss chard, turnips

8. August

   Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hydrangeas, kale, lettuce, lilies, ornamental alliums, peonies, radishes, roses, saffron, snapdragons, spinach, tulips, turnips

9. September

   Plant for fall: crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, kale, lilies, ornamental alliums, peonies, radishes, saffron, tulips

10. October

    Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips

Frost dates and zones by ZIP code in Castle Rock

Castle Rock's 3 main ZIP codes take their frost dates from 2 different NOAA stations: the typical last frost ranges from May 9 in 80108 to May 16 in 80104. Every one of them is in zone 5b.

Planting dates for popular crops in Castle Rock

Nearby cities

• Parker, CO zone 5b, last frost May 9
• Centennial, CO zone 6a, last frost May 5
• Aurora, CO zone 6a, last frost May 4
• Lakewood, CO zone 6a, last frost May 5
• Denver, CO zone 6a, last frost May 4
• Commerce City, CO zone 6a, last frost May 4