One of the first steps you take when you are estimating 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 common way of getting a good idea when it's the best time to plant oxalis is to look at the USDA zone info for Umatilla.

Planting Calendar for Oxalis

Frost tolerance for oxalis:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since oxalis require warm weather it's important to wait until after the last frost before you can plant them.

The earliest that you can plant oxalis in Umatilla 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 oxalis and expect a good harvest is probably August. If you wait any later than that and your oxalis may not have a chance to really do well. Starting your oxalis indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Umatilla the average date of last frost happens on April 15. You can expect an average low temperature of 5°F in the coldest months of winter.

Since the USDA zone info for Umatilla is just an average the actual date of last frost changes from year to year. Since half of the time in Umatilla there is a last frost after April 15 be ready to cover your oxalis if you have one of those late frosts.

USDA Zone Info for Umatilla

Here is the info for USDA Zone 7b.

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

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

Plants to Grow in Umatilla

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