One of the best tools that you have as gardeners to help us determine 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.

A common way of estimating when it's possible to plant geranium is to check out the USDA zone info for San Marcos.

Planting Calendar for Geranium

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

It's a bad idea to plant geranium until after the last frost because they are not cold tolerant.

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

Last Frost Date

In San Marcos the average date of last frost happens on March 15. You can expect an average low temperature of 15°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for San Marcos and it will vary from year to year. Half of the time in San Marcos last frost occurs after March 15 so make sure that you are prepared to protect your geranium in the event of one of those late frosts.

USDA Zone Info for San Marcos

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 San Marcos

You may be interested in your other planting guides for San Marcos.