One of the first steps you take when you are estimating your gardening schedule is find your 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.

By looking at the USDA zone info for Tomball it's a good idea to figure out when you can plant skullcap.

Planting Calendar for Skullcap

Frost tolerance for skullcap:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since skullcap do not do well in cold weather it's necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant skullcap in Tomball 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 skullcap and expect a good harvest is probably September. Any later than that and your skullcap may not have a chance to fully mature. If you are starting your skullcap indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Tomball the average date of last frost happens on February 15. It might get as low as 20°F during 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 Tomball and it will vary from year to year. Half of the time in Tomball there is a last frost after February 15 so make sure that you are prepared to protect your skullcap if you have one of those late frosts.

USDA Zone Info for Tomball

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Tomball

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