Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Renton you can estimate when it's the best time to plant zinnia by checking out the USDA zone info.

Planting Calendar for Zinnia

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

Since zinnia require warm weather it is necessary to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant zinnia in Renton 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 zinnia and expect a good harvest is probably August. Any later than that and your zinnia may not have a chance to really do well. Starting your zinnia indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Renton may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Renton you get surprised by a frost after March 15 be ready to cover your zinnia in the event of a surprise late frost.

USDA Zone Info for Renton

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 Renton

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