WHEN TO PLANT
Wait...don't try to jump the gun on planting! Most spring annuals can't be planted until after the danger of killing frost has passed; refer to the chart on hardiness for more details. Many warm season plants, such as periwinkles and caladiums, cannot tolerate cool soil temperature. Delay planting until the medium reaches 70 degrees.
Discard any plants that may have reseeded themselves from last season. They'll be less vigorous and may not resemble their hybrid parents. If it's not possible for you to plant right away, keep plants in a lightly shaded spot and be sure to water them as needed. If possible, it is best to plant on a cloudy or overcast day or late in the day to reduce transplanting shock.