Use this planting calendar to find the best times of the year to grow fruits, vegetables, herbs, flowers, and other popular plants in Mercer island, WA, based on the USDA Hardiness Zone 9a.
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Mercer island, WA Frost Dates & Growing Season
Last Spring Frost Date for Mercer island, WA
The average last frost date in spring for Mercer island is March 25th. For gardeners planting sensitive crops like tomatoes, peppers, and basil, it is generally recommended to wait until April 8th 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 Mercer island, WA
The average first frost date in fall for Mercer island is November 1st. 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 Mercer island, WA
Based on historical frost data, the estimated growing season length in Mercer island is approximately 221 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.
Mercer island, WA Planting Calendar
This weekly planting calendar displays the ideal windows for starting seeds, transplanting, and harvesting your plants.
Mercer island, WA Monthly Planting Recommendations
January
In January, recommended activities include starting Coleus seeds indoors (from January 28th to February 11th), starting French Lavender seeds indoors (from January 14th to January 28th), and starting Onion seeds indoors (from January 14th to January 28th).
February
In February, recommended activities include direct sowing California Poppy (from February 25th to March 11th), direct sowing Chives (from February 25th to March 11th), and starting Brussel Sprout seeds indoors (from February 11th to February 25th).
March
In March, recommended activities include direct sowing Beet (from March 11th to March 25th), direct sowing Lemon Balm (from March 25th to April 8th), and direct sowing Calendula (from March 11th to March 25th).
April
In April, recommended activities include direct sowing Runner Bean (from April 1st to April 15th), direct sowing Lima Bean (from April 8th to April 22nd), and direct sowing Okra (from April 8th to April 22nd).