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.

You will be able to estimate when it's the best time to plant tall phlox by using the USDA zone info for Prosser.

Planting Calendar for Tall Phlox

Frost tolerance for tall phlox:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Tall Phlox do well in a little bit of cold which tells us that you can plant them just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant tall phlox in Prosser is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant tall phlox and expect a good harvest is probably September. You probably don't want to wait any later than that or else your tall phlox may not have a chance to grow to maturity. If you are starting your tall phlox indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Prosser. It might get as low as 0°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Prosser is an average and the actual date of last frost is different every year. Half of the time in Prosser last frost occurs after April 15 so make sure that you are ready to protect your tall phlox in the event of a late frost.

USDA Zone Info for Prosser

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 Prosser

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