Before planting it is a good idea to find your USDA Zone info to figure out 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.

You can figure out when it's possible to plant onions in Rio Grande City by looking at the USDA zone info.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since onions do well in cold you can plant them much earlier in the year than other frost tender plants.

The earliest that you can plant onions in Rio Grande City is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant onions and expect a good harvest is probably October. Any later than that and your onions may not have a chance to really do well. You can get started a few weeks earlier by starting your onions indoors.

Last Frost Date

The average date of last frost is February 15 in Rio Grande City. In the coldest months of winter you should expect an average low temperature of 25°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Rio Grande City and it can change quite a bit from year to year. Since half of the time in Rio Grande City you get a frost after February 15 be ready to protect your onions in the event of a surprise 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 Low	25°F
Highest Expected Low	30°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.