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 USDA zone info for Renton should be used to estimate when to plant romanesco.

Planting Calendar for Romanesco

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

Since romanesco do well in moderate cold you can plant them just a bit earlier in the year than more sensitive plants.

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

Last Frost Date

On average all chance of frost has passed is on March 15 in Renton. You should expect an average low temperature of 15°F in the coldest months of winter.

Keep in mind that USDA zone info for Renton is an average and the actual date of last frost will vary from year to year. Since half of the time in Renton you get surprised by a frost after March 15 be ready to cover your romanesco if you have one of those late frosts.

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.