One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to figure out when it's the best time to plant lithospermum by referring to the USDA zone info for Manhattan.

Planting Calendar for Lithospermum

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

Lithospermum require warm weather which tells us that it is important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant lithospermum in Manhattan is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant lithospermum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lithospermum may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your lithospermum indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Manhattan. You can expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Manhattan is an average the actual date of last frost is different every year. Since half of the time in Manhattan you get surprised by a frost after April 15 be ready to cover your lithospermum in the event of a surprise late frost.

USDA Zone Info for Manhattan

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 Manhattan

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