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

You can figure out when it's possible to plant parsnip in Thornton by reviewing the USDA zone info.

Planting Calendar for Parsnip

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

Parsnip can survive in moderate cold which tells us that you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant parsnip in Thornton 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 parsnip and expect a good harvest is probably September. Any later than that and your parsnip may not have a chance to fully mature. Starting your parsnip indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Thornton. In the coldest months of winter you should expect an average low temperature of -15°F.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Thornton and it will vary from year to year. Half of the time in Thornton you get a frost after April 15 so be sure to be ready to protect your parsnip if you have 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.