One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant polygonums in Wapato should be figured out by using the USDA zone info.

Planting Calendar for Polygonums

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

Since polygonums are not cold tolerant you have to wait until after the last frost has passed before you can plant them.

The earliest that you can plant polygonums in Wapato 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 polygonums and expect a good harvest is probably August. Any later than that and your polygonums may not have a chance to grow to maturity. Starting your polygonums indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Wapato. In the coldest months of winter you can expect an average low temperature of -5°F.

Since the USDA zone info for Wapato is an average the actual date of last frost changes from year to year. Half of the time in Wapato you get a frost after April 15 so make sure that you are ready to protect your polygonums in the event of a surprise late frost.

USDA Zone Info for Wapato

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°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 0°F.

Plants to Grow in Wapato

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