The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Hillsborough you can determine when it's the best time to plant zinnia by referring to the USDA zone info.

Planting Calendar for Zinnia

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

It's not a good idea to plant zinnia until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant zinnia in Hillsborough 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. You probably don't want to wait any later than that or else your zinnia may not have a chance to grow to maturity. Starting your zinnia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Hillsborough. In the coldest months of winter you should expect an average low temperature of 5°F.

Since the USDA zone info for Hillsborough may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Hillsborough it frosts late in the year after April 15 so always be ready to cover your zinnia in the event of one of those late frosts.

USDA Zone Info for Hillsborough

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Hillsborough

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