Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to estimate when to plant sweet sultan by reviewing the USDA zone info for Keokuk.

Planting Calendar for Sweet Sultan

Frost tolerance for sweet sultan:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since sweet sultan are barely cold tolerant you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant sweet sultan in Keokuk is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant sweet sultan and expect a good harvest is probably August. If you wait any later than that and your sweet sultan may not have a chance to fully mature. If you are starting your sweet sultan indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Remember that USDA zone info for Keokuk is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Keokuk there is a last frost after April 15 so make sure that you are prepared to protect your sweet sultan if you have a surprise late frost.

USDA Zone Info for Keokuk

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 Keokuk

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