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When to Plant Flower-of-an-Hour in Mercer Island, WA

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of estimating when it's possible to plant flower-of-an-hour is to refer to the USDA zone info for Mercer Island.


Planting Calendar for Flower-of-an-Hour

Frost tolerance for flower-of-an-hour: Tolerant of a very small amount of frost.
When to plant: Up to 3 weeks before last frost.

You can plant flower-of-an-hour slightly earlier in the year because they are barely cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant flower-of-an-hour
Possibly ok, but a risky time to plant flower-of-an-hour
Probably not a good time to plant flower-of-an-hour

The earliest that you can plant flower-of-an-hour in Mercer Island is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant flower-of-an-hour and expect a good harvest is probably August. You probably don't want to wait any later than that or else your flower-of-an-hour may not have a chance to grow to maturity. If you are starting your flower-of-an-hour indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Mercer Island. It might get as low as 15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Mercer Island and it is different every year. Since half of the time in Mercer Island last frost occurs after March 15 be ready to protect your flower-of-an-hour in the event of a late frost.

USDA Zone Info for Mercer Island

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)March 15
Average Date of First Frost (fall)November 15
Lowest Expected Low15°F
Highest Expected Low20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Mercer Island

You may be interested in your other planting guides for Mercer Island.