Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Helena you will be able to determine when it's possible to plant basil.

Planting Calendar for Basil

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

Basil are not cold tolerant which tells us that you really should wait until it warms up after the last frost when the weather gets warmer before you can plant them.

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

Last Frost Date

The average date of last frost is March 15 in Helena. You should expect an average low temperature of 10°F in the coldest months of winter.

Since the USDA zone info for Helena is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Helena it frosts late in the year after March 15 be ready to protect your basil if you have one of those late frosts.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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