One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of making a decision about when it's the best time to plant catharanthus is to examine the USDA zone info for Seward.

Planting Calendar for Catharanthus

Frost tolerance for catharanthus:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably not a good idea to plant catharanthus until after the last frost has passed because they require warm weather.

The earliest that you can plant catharanthus in Seward 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 catharanthus and expect a good harvest is probably August. Any later than that and your catharanthus may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your catharanthus indoors.

Last Frost Date

The average date of last frost is April 15 in Seward. In the coldest months of winter you can expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Seward is an average and the actual date of last frost is different every year. Half of the time in Seward you get a frost after April 15 so make sure that you are ready to protect your catharanthus in the event of a surprise late frost.

USDA Zone Info for Seward

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 Seward

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