One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to determine when to plant welsh onion by referring to the USDA zone info for Robstown.

Planting Calendar for Welsh onion

Frost tolerance for welsh onion:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant welsh onion slightly earlier in the year because they do ok in moderate cold.

The earliest that you can plant welsh onion in Robstown is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant welsh onion and expect a good harvest is probably September. If you wait any later than that and your welsh onion may not have a chance to grow to maturity. Starting your welsh onion indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Robstown. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Robstown may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Robstown there is a last frost after February 15 so make sure that you are prepared to protect your welsh onion in the event of a surprise late frost.

USDA Zone Info for Robstown

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 Robstown

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