When to Plant Sunflowers in Cornelius, OR

One of the best tools that you have as gardeners to help us figure out 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.

You can determine when you can plant sunflowers in Cornelius by using the USDA zone info.


Planting Calendar for Sunflowers

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

Since sunflowers are not cold tolerant you really should wait until after all chance of frost has passed before you can plant them.

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 Cornelius 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. Any later than that and your sunflowers may not have a chance to fully mature. You can get started a little bit earlier by starting your sunflowers indoors.

Last Frost Date

In Cornelius the average date of last frost happens on March 15. It might get as low as 15°F during the coldest months of winter.

Remember that USDA zone info for Cornelius is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Cornelius last frost occurs after March 15 be ready to protect your sunflowers if you have a late frost.

USDA Zone Info for Cornelius

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 Cornelius

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