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When to Plant Balloon Flower in Thornton, CO

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.

The best time to plant balloon flower in Thornton can be determined by reviewing the USDA zone info.


Planting Calendar for Balloon Flower

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

Since balloon flower are barely cold tolerant you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant balloon flower
Possibly ok, but a risky time to plant balloon flower
Probably not a good time to plant balloon flower

The earliest that you can plant balloon flower 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 balloon flower and expect a good harvest is probably August. You probably don't want to wait any later than that or else your balloon flower may not have a chance to really do well. If you are starting your balloon flower indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Thornton the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Thornton and it changes from year to year. Half of the time in Thornton you get a frost after April 15 so just be sure to be ready to cover your balloon flower in the event of one of those late frosts.

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.