Could be a number of things Fuggy, including over watering, under watering, cold nights, or the stress of replanting. You don't say whether they are in a greenhouse(in which case it could be a bacterial problem) or outside. When the weather warms up and dries out, the problem will probably go away on its own. You can help prevent the spread of disease by clipping off and destroying affected flowers and leaves. Give plants wider spacing so they'll have better airflow around them and dry out more quickly. Use drip irrigation, if necessary, to avoid wetting foliage and flowers when watering. If the problem persists, spray with a protective fungicide.