Try to plant in a location that enjoys full sun and remember to water moderately. Keep in mind when planting that Car Wash is thought of as hardy, so this plant will grow or become dormant during the winter.
Growing Car Wash from seed
By our calculations, you should look at sowing Car Wash about 56 days before your last frost date.
Transplanting Car Wash
As Car Wash is hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.