One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Boulder you can estimate when you can plant dill by referring to the USDA zone info.

Planting Calendar for Dill

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

Dill are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than more sensitive plants.

The earliest that you can plant dill 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 dill and expect a good harvest is probably August. If you wait any later than that and your dill may not have a chance to really do well. You can get started a few weeks earlier by starting your dill indoors.

Last Frost Date

On average the last frost is on April 15 in Boulder. It might get as low as -15°F during the coldest months of winter.

It's important to remember that USDA zone info for Boulder is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Boulder you get a frost after April 15 so always be ready to protect your dill if you have 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.