Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By reviewing the USDA zone info for Lake Oswego it's a good idea to figure out when it's the best time 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.

You can plant gomphrena just a tiny bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant gomphrena in Lake Oswego 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 grow to maturity. You can get started a few weeks earlier by starting your gomphrena indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Lake Oswego. It might get as low as 15°F during the coldest months of winter.

Since the USDA zone info for Lake Oswego is not always accurate the actual date of last frost is different every year. Since half of the time in Lake Oswego you get a frost after March 15 be ready to protect your gomphrena in the event of a surprise late frost.

USDA Zone Info for Lake Oswego

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 Lake Oswego

You may be interested in your other planting guides for Lake Oswego.