Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Boulder it's a good idea to determine when you can plant salsify.

Planting Calendar for Salsify

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

Salsify are one of those plants that can tolerate a tiny bit of cold weather which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant salsify in Boulder 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 salsify and expect a good harvest is probably August. If you wait any later than that and your salsify may not have a chance to fully mature. Starting your salsify indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Boulder. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Boulder is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Boulder you get surprised by a frost after April 15 be ready to protect your salsify in the event of a surprise late frost.

USDA Zone Info for Boulder

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Boulder

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