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When to Plant Sunflowers in Rio Grande City, TX

One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of estimating when it's the best time to plant sunflowers is to look at the USDA zone info for Rio Grande City.


Planting Calendar for Sunflowers

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

It's probably a bad idea to plant sunflowers until after the last 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 Rio Grande City 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 sunflowers and expect a good harvest is probably September. You probably don't want to wait any later than that or else your sunflowers may not have a chance to fully mature. If you are starting your sunflowers indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Rio Grande City the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Rio Grande City and it changes from year to year. Half of the time in Rio Grande City there is a last frost after February 15 so just be sure to be ready to cover your sunflowers in the event of a late frost.

USDA Zone Info for Rio Grande City

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)February 15
Average Date of First Frost (fall)December 15
Lowest Expected Low25°F
Highest Expected Low30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Rio Grande City

You may be interested in your other planting guides for Rio Grande City.