One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

A way of estimating when it's the best time to plant zinnia is to examine the USDA zone info for Preston.

Planting Calendar for Zinnia

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

Zinnia do not do well in cold weather which tells us that it is important to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant zinnia in Preston 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 zinnia and expect a good harvest is probably August. If you wait any later than that and your zinnia may not have a chance to grow to maturity. Starting your zinnia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Preston is an average the actual date of last frost changes from year to year. Half of the time in Preston there is a last frost after April 15 so make sure that you are ready to cover your zinnia in the event of one of those late frosts.

USDA Zone Info for Preston

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 Preston

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