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.

A common way of estimating when you can plant cosmos is to consult the USDA zone info for Highland.

Planting Calendar for Cosmos

Frost tolerance for cosmos:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Cosmos do well in very little cold which means that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant cosmos in Highland 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 cosmos and expect a good harvest is probably August. If you wait any later than that and your cosmos may not have a chance to grow to maturity. You can get started a little bit earlier by starting your cosmos indoors.

Last Frost Date

In Highland the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Remember that USDA zone info for Highland is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Highland you get surprised by a frost after April 15 be ready to protect your cosmos in the event of a surprise late frost.

USDA Zone Info for Highland

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 Highland

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