One of the first steps you take when you are getting a good idea 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.

A common way of figuring out when it's the best time to plant diascia is to refer to the USDA zone info for Colby.

Planting Calendar for Diascia

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

Diascia do well in moderate cold which means that you can plant them earlier than other frost tender plants.

The earliest that you can plant diascia in Colby 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 diascia and expect a good harvest is probably September. You probably don't want to wait any later than that or else your diascia may not have a chance to grow to maturity. If you are starting your diascia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Colby the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Remember that USDA zone info for Colby may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Colby there is a last frost after April 15 so be sure to be ready to protect your diascia if you have one of those late frosts.

USDA Zone Info for Colby

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 Colby

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