The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Portland you can determine when it's possible to plant tropical water plants by using the USDA zone info.

Planting Calendar for Tropical Water Plants

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

Tropical Water Plants do not do well in cold weather which means that it is important to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant tropical water plants 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 tropical water plants and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tropical water plants may not have a chance to grow to maturity. If you are starting your tropical water plants indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost is on March 15 in Portland. You can expect an average low temperature of 15°F in the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year 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 you get a frost after March 15 so always be ready to protect your tropical water plants if you have a late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Portland

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