When to Plant Sunflowers in Louisville, CO

Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant sunflowers in Louisville should be figured out 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 has passed.

You can not plant sunflowers until after all chance of frost has passed because they require warm 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 Louisville 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 grow to maturity. You can get started a couple of weeks earlier by starting your sunflowers indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Louisville. It might get as low as -10°F during the coldest months of winter.

Keep in mind that USDA zone info for Louisville is an average and the actual date of last frost is different every year. Since half of the time in Louisville it frosts late in the year after April 15 be ready to cover your sunflowers in the event of one of those late frosts.

USDA Zone Info for Louisville

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-10°F
Highest Expected Low-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Louisville

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