The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's the best time to plant geranium in Thornton by reviewing the USDA zone info.

Planting Calendar for Geranium

Frost tolerance for geranium:	Not tolerant of frost.
When to plant:	After the last frost.

You should not plant geranium until after all chance of frost has passed because they require warm weather.

The earliest that you can plant geranium in Thornton is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant geranium and expect a good harvest is probably August. If you wait any later than that and your geranium may not have a chance to fully mature. You can get started a little bit earlier by starting your geranium indoors.

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 USDA zone info for Thornton may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Thornton it frosts late in the year after April 15 so be sure to be ready to cover your geranium in the event of a 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.