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.

A common way of estimating when to plant delphinium is to consult the USDA zone info for Brownsburg.

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.

Delphinium can survive in very little cold which tells us that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant delphinium in Brownsburg 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. Any later than that and your delphinium may not have a chance to fully mature. You can get started a little bit earlier by starting your delphinium indoors.

Last Frost Date

On average the last frost is on April 15 in Brownsburg. You should expect an average low temperature of -15°F in the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Brownsburg and it can change quite a bit from year to year. Since half of the time in Brownsburg it frosts late in the year after April 15 be ready to protect your delphinium in the event of a late frost.

USDA Zone Info for Brownsburg

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 Brownsburg

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