One of the first steps you take when you are figuring out your gardening schedule is find your 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 making a decision about when it's a good idea to plant tithonia is to look at the USDA zone info for Alton.

Planting Calendar for Tithonia

Frost tolerance for tithonia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably not a good idea to plant tithonia until after the last frost has passed because they require warm weather.

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

Last Frost Date

In Alton the average date of last frost happens on April 15. It might get as low as -10°F during the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Alton and it will vary from year to year. Half of the time in Alton last frost occurs after April 15 so just be sure to be ready to protect your tithonia if you have a surprise late frost.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Alton

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