One of the first steps you take when you are determining 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.

The earliest that you can plant lavender in Boulder should be figured out by using the USDA zone info.

Planting Calendar for Lavender

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

Since lavender are one of those plants that can tolerate a little bit of cold weather you can plant them a little earlier in the year than other frost tender plants.

The earliest that you can plant lavender in Boulder is February. However, you really should wait until March if you don't want to take any chances.

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

Last Frost Date

In Boulder the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Boulder and it changes from year to year. Half of the time in Boulder you get a frost after April 15 so make sure that you are prepared to protect your lavender in the event of a 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.