The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Douglas you should be able to estimate when you can plant jerusalem artichokes.

Planting Calendar for Jerusalem artichokes

Frost tolerance for jerusalem artichokes:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Jerusalem artichokes do well in moderate cold which means that you can get them planted earlier than other plants that might not handle the cold.

The earliest that you can plant jerusalem artichokes in Douglas 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 jerusalem artichokes and expect a good harvest is probably August. If you wait any later than that and your jerusalem artichokes may not have a chance to grow to maturity. If you are starting your jerusalem artichokes indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Douglas the average date of last frost happens on May 15. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Douglas is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Douglas there is a last frost after May 15 so make sure that you are ready to protect your jerusalem artichokes if you have one of those late frosts.

USDA Zone Info for Douglas

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Douglas

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