The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when to plant lithospermum is to look at the USDA zone info for Humble.

Planting Calendar for Lithospermum

Frost tolerance for lithospermum:	Not tolerant of frost.
When to plant:	After the last frost.

Lithospermum are not cold tolerant which tells us that it is important to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant lithospermum in Humble 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 lithospermum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your lithospermum may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your lithospermum indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on February 15 in Humble. It might get as low as 20°F during the coldest months of winter.

It's important to remember that USDA zone info for Humble 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 Humble last frost occurs after February 15 so just be sure to be ready to cover your lithospermum in the event of a late frost.

USDA Zone Info for Humble

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 Humble

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