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.

One way of determining when it's a good idea to plant heliotrope is to look at the USDA zone info for Astoria.

Planting Calendar for Heliotrope

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

Since heliotrope are not cold tolerant you really should wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant heliotrope in Astoria 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 heliotrope and expect a good harvest is probably August. Any later than that and your heliotrope may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your heliotrope indoors.

Last Frost Date

The average date of last frost is March 15 in Astoria. In the coldest months of winter you can expect an average low temperature of 15°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Astoria and it will vary from year to year. Half of the time in Astoria it frosts late in the year after March 15 so just be sure to be ready to protect your heliotrope in the event of a surprise late frost.

USDA Zone Info for Astoria

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 Astoria

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