One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Sammamish should be read to estimate when to plant gomphrena.

Planting Calendar for Gomphrena

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

Gomphrena do ok in moderate cold which tells us that you can start planting them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant gomphrena in Sammamish 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 gomphrena and expect a good harvest is probably August. You probably don't want to wait any later than that or else your gomphrena may not have a chance to really do well. If you are starting your gomphrena indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Sammamish. It might get as low as 15°F during the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Sammamish and it is different every year. Half of the time in Sammamish there is a last frost after March 15 so just be sure to be ready to protect your gomphrena if you have one of those late frosts.

USDA Zone Info for Sammamish

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 Low	15°F
Highest Expected Low	20°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 Sammamish

You may be interested in your other planting guides for Sammamish.