One of the best tools that you have as gardeners to help us determine 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.

A way of figuring out when to plant trifolium is to refer to the USDA zone info for Denver.

Planting Calendar for Trifolium

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

You can plant trifolium a bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant trifolium in Denver 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 trifolium and expect a good harvest is probably August. You probably don't want to wait any later than that or else your trifolium may not have a chance to really do well. Starting your trifolium 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 Denver. In the coldest months of winter you should expect an average low temperature of -15°F.

Always keep in mind that USDA zone info for Denver is an average and the actual date of last frost will vary from year to year. Half of the time in Denver you get surprised by a frost after April 15 so make sure that you are ready to cover your trifolium in the event of a late frost.

USDA Zone Info for Denver

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 Denver

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