Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By checking out the USDA zone info for Colby you will be able to estimate when you can plant platycodon.

Planting Calendar for Platycodon

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

Since platycodon are barely cold tolerant you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant platycodon in Colby 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 platycodon and expect a good harvest is probably August. You probably don't want to wait any later than that or else your platycodon may not have a chance to grow to maturity. Starting your platycodon indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Colby and it changes from year to year. Half of the time in Colby you get a frost after April 15 so always be ready to protect your platycodon if you have a late frost.

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.