One of the first steps you take when you are estimating your gardening schedule is find your 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.

The first chance to plant platycodon in Thornton should be determined by referring to the USDA zone info.

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.

Platycodon are barely cold tolerant which tells us that you can get them planted just a bit earlier than plants that are more sensitive to the cold.

The earliest that you can plant platycodon in Thornton 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. You can get started a few weeks earlier by starting your platycodon indoors.

Last Frost Date

The average date of last frost is April 15 in Thornton. In the coldest months of winter you should expect an average low temperature of -15°F.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Thornton and it changes from year to year. Since half of the time in Thornton you get a frost after April 15 be ready to cover your platycodon in the event of a surprise late frost.

USDA Zone Info for Thornton

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 Thornton

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