One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can determine when it's the best time to plant sunflowers in Alamosa by referring to the USDA zone info.

Planting Calendar for Sunflowers

Frost tolerance for sunflowers:	Not tolerant of frost.
When to plant:	After the last frost.

Sunflowers do not do well in cold weather which means that you need to 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 sunflowers in Alamosa is May. However, you really should wait until June if you don't want to take any chances.

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

Last Frost Date

On average the last frost is on May 15 in Alamosa. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Alamosa is an average the actual date of last frost is different every year. Half of the time in Alamosa it frosts late in the year after May 15 so make sure that you are prepared to protect your sunflowers in the event of a surprise late frost.

USDA Zone Info for Alamosa

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Alamosa

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