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.

In Richardson you can determine when it's possible to plant tree onions by looking at the USDA zone info.

Planting Calendar for Tree onions

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

You can plant tree onions just a tiny bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant tree onions in Richardson 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 tree onions and expect a good harvest is probably August. Any later than that and your tree onions may not have a chance to grow to maturity. If you are starting your tree onions indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is March 15 in Richardson. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Richardson may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Richardson you get surprised by a frost after March 15 be ready to protect your tree onions if you have a late frost.

USDA Zone Info for Richardson

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Richardson

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