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.

The best time to plant salpiglossis in Johnston can be determined by checking out the USDA zone info.

Planting Calendar for Salpiglossis

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

Salpiglossis require warm weather which means that it is necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant salpiglossis in Johnston 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 salpiglossis and expect a good harvest is probably August. Any later than that and your salpiglossis may not have a chance to grow to maturity. Starting your salpiglossis indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Johnston. In the coldest months of winter you can expect an average low temperature of -20°F.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Johnston and it will vary from year to year. Half of the time in Johnston you get surprised by a frost after April 15 so make sure that you are prepared to protect your salpiglossis in the event of a late frost.

USDA Zone Info for Johnston

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Johnston

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