When to Plant Delphinium in Brighton, CO

Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant delphinium in Brighton should be estimated by using the USDA zone info.


Planting Calendar for Delphinium

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

You can plant delphinium just a tiny bit earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

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

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

Last Frost Date

The average date of last frost is April 15 in Brighton. You can expect an average low temperature of -15°F in the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Brighton and it changes from year to year. Half of the time in Brighton it frosts late in the year after April 15 so always be ready to protect your delphinium in the event of a surprise late frost.

USDA Zone Info for Brighton

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 Brighton

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