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.

A way of getting a good idea when it's the best time to plant marigold is to look at the USDA zone info for Swarthmore.

Planting Calendar for Marigold

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

Marigold do not do well in cold weather which means that it is important to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant marigold in Swarthmore 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 marigold and expect a good harvest is probably August. You probably don't want to wait any later than that or else your marigold may not have a chance to grow to maturity. Starting your marigold indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Swarthmore. You should expect an average low temperature of 0°F in the coldest months of winter.

It's important to remember that USDA zone info for Swarthmore is just an average and the actual date of last frost is different every year. Half of the time in Swarthmore there is a last frost after April 15 so just be sure to be ready to protect your marigold in the event of a surprise late frost.

USDA Zone Info for Swarthmore

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Swarthmore

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