Use this planting calendar to find the best times of the year to grow fruits, vegetables, herbs, flowers, and other popular plants in Hillsborough, CA, based on the USDA Hardiness Zone 10a.
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Hillsborough, CA Frost Dates & Growing Season
Last Spring Frost Date for Hillsborough, CA
The average last frost date in spring for Hillsborough is January 15th. For gardeners planting sensitive crops like tomatoes, peppers, and basil, it is generally recommended to wait until January 29th 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 Hillsborough, CA
The average first frost date in fall for Hillsborough is December 15th. 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 Hillsborough, CA
Based on historical frost data, the estimated growing season length in Hillsborough is approximately 334 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.
Hillsborough, CA Planting Calendar
This weekly planting calendar displays the ideal windows for starting seeds, transplanting, and harvesting your plants.
Hillsborough, CA Monthly Planting Recommendations
January
In January, recommended activities include direct sowing Lemon Balm (from January 15th to January 29th), direct sowing Zinnia (from January 22nd to February 5th), and direct sowing Watermelon (from January 29th to February 12th).
November
In November, recommended activities include starting Tomato seeds indoors (from November 20th to December 4th), starting Black Eyed Susan seeds indoors (from November 20th to December 4th), and starting Begonia seeds indoors (from November 6th to November 20th).
December
In December, recommended activities include starting Pumpkin seeds indoors (from December 25th to January 1st), direct sowing Arugula (from December 18th to January 1st), and direct sowing Sweet Pea (from December 18th to January 1st).