One of the best tools that you have as gardeners to help us estimate 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.

The best time to plant lisianthus in Portland can be figured out by referring to the USDA zone info.

Planting Calendar for Lisianthus

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

It's probably a bad idea to plant lisianthus until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant lisianthus in 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 lisianthus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your lisianthus may not have a chance to really do well. You can get started a little bit earlier by starting your lisianthus indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Portland. In the coldest months of winter you should expect an average low temperature of 0°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Portland and it can change quite a bit from year to year. Half of the time in Portland last frost occurs after April 15 so be sure to be ready to cover your lisianthus if you have a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Portland

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