One of the best tools that you have as gardeners to help us determine 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 a good idea to plant nierembergia is to consult the USDA zone info for Madison.

Planting Calendar for Nierembergia

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

Since nierembergia require warm weather it's important to wait until after the last frost when the weather gets warmer before you can plant them.

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

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Madison. In the coldest months of winter you can expect an average low temperature of 10°F.

Since the USDA zone info for Madison is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Madison you get a frost after March 15 so just be sure to be ready to cover your nierembergia if you have one of those late frosts.

USDA Zone Info for Madison

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Madison

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