One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when to plant delphinium in Hummelstown by reviewing 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.

Delphinium can survive in a tiny bit of cold which means that you can plant them just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant delphinium in Hummelstown 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. If you wait any later than that and your delphinium may not have a chance to fully mature. If you are starting your delphinium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Hummelstown. In the coldest months of winter you can expect an average low temperature of 0°F.

Keep in mind that USDA zone info for Hummelstown is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Hummelstown you get surprised by a frost after April 15 so make sure that you are prepared to protect your delphinium in the event of a late frost.

USDA Zone Info for Hummelstown

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Hummelstown

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