Annuals bloom better if the old flowers are removed. This prevents seed formation that normally makes annuals start to decline. The practice is particularly important when growing ageratum, calendula, cosmos, marigold, pansy, rudbeckia, scabiosa, verbena, and zinnia.
Lead in soil can be a hazard when children play in bare soil or when people bring soil into the house on their shoes. The following two federal standards have been set for lead hazards in residential soil: 400 parts per million (ppm) and higher in play areas of bare soil; 1,200 ppm (average) and higher in bare soil in the remainder of the yard. The only way to find out if soil lead hazards exist is to test.