Use this planting calendar to find the best times of the year to grow fruits, vegetables, herbs, flowers, and other popular plants in Castle rock, CO, based on the USDA Hardiness Zone 5b.
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Castle rock, CO Frost Dates & Growing Season
Last Spring Frost Date for Castle rock, CO
The average last frost date in spring for Castle rock is May 19th. For gardeners planting sensitive crops like tomatoes, peppers, and basil, it is generally recommended to wait until June 2nd before moving plants outdoors. Waiting these extra few weeks significantly reduces the risk of a late freeze damaging young transplants.
First Fall Frost Date for Castle rock, CO
The average first frost date in fall for Castle rock is October 5th. This date marks the approximate end of the growing season for tender plants. Gardeners should plan to harvest frost-sensitive vegetables or provide heavy protection (such as row covers) before this date to avoid crop loss.
Growing Season Length in Castle rock, CO
Based on historical frost data, the estimated growing season length in Castle rock is approximately 139 days. This duration determines which vegetable varieties have enough time to reach maturity before the winter cold sets in. Short-season varieties are recommended for crops that require a longer warm period.
Please note: These dates are climatological averages. Actual weather conditions vary by year. Always check the local 10-day forecast before planting.
Castle rock, CO Planting Calendar
This weekly planting calendar displays the ideal windows for starting seeds, transplanting, and harvesting your plants.
Castle rock, CO Monthly Planting Recommendations
March
In March, recommended activities include starting Aubergine seeds indoors (from March 24th to April 7th), starting Coneflower seeds indoors (from March 24th to April 7th), and starting Onion seeds indoors (from March 10th to March 24th).
April
In April, recommended activities include direct sowing Crimson Clover (from April 21st to May 5th), direct sowing Poppy (from April 21st to May 5th), and direct sowing Sweet Pea (from April 21st to May 5th).
May
In May, recommended activities include direct sowing Butternut Squash (from May 26th to June 9th), direct sowing Gladiolus (from May 19th to June 2nd), and direct sowing Calendula (from May 5th to May 19th).
June
In June, recommended activities include direct sowing Melon (from June 2nd to June 16th), direct sowing Butterfly Pea (from June 2nd to June 16th), and direct sowing Chia (from June 2nd to June 16th).