When to Plant Sunflowers in Gladstone, OR

The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to estimate when to plant sunflowers by checking out the USDA zone info for Gladstone.


Planting Calendar for Sunflowers

Frost tolerance for sunflowers: Not tolerant of frost.
When to plant: After the last frost has passed.

You can not plant sunflowers until after all chance of frost has passed because they do not do well in cold weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant sunflowers
Possibly ok, but a risky time to plant sunflowers
Probably not a good time to plant sunflowers

The earliest that you can plant sunflowers in Gladstone is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant sunflowers and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sunflowers may not have a chance to grow to maturity. Starting your sunflowers indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on March 15 in Gladstone. You can expect an average low temperature of 15°F in 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 Gladstone and it will vary from year to year. Since half of the time in Gladstone there is a last frost after March 15 be ready to protect your sunflowers if you have a late frost.

USDA Zone Info for Gladstone

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 Gladstone

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