One of the best tools that you have as gardeners to help us determine your gardening schedule is the 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 getting a good idea when to plant nasturtium is to look at the USDA zone info for South Portland.

Planting Calendar for Nasturtium

Frost tolerance for nasturtium:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's a bad idea to plant nasturtium until after the last frost because they require warm weather.

The earliest that you can plant nasturtium in South Portland 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 nasturtium and expect a good harvest is probably August. You probably don't want to wait any later than that or else your nasturtium may not have a chance to fully mature. Starting your nasturtium indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in South Portland. In the coldest months of winter you should expect an average low temperature of -15°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 South Portland and it can change quite a bit from year to year. Since half of the time in South Portland last frost occurs after April 15 be ready to protect your nasturtium if you have one of those late frosts.

USDA Zone Info for South Portland

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 South Portland

You may be interested in your other planting guides for South Portland.