Question
Why are my purple wave petunias dying? They were full and beautiful two weeks ago.  Now they are brown at the root and are dying.  I water everyday, and they are in full sun. What's up with this flower?

Answer
Lynne,
Brown roots or stems at ground level are a sign of root rot/crown rot. Might you be keeping them too damp? In general, annuals (including Wave petunias) do best with a deep soaking less often. So watering with a sprinkler every four days for 40 minutes when first planted, and then once established every six days, is better than every day watering. If it's really sunny and hot where you live they might need it more often than that, especially when first planted.  Part of the timing of watering also depends on your soil: if you have rich loam, or heavy clay, you have to water less often than if you have sandy loam.

If these are in a container, they might need watering every day, but if they are in a container that drains the excess out, and it is sunny and warm where you are, they can take every day or every other day and will do well. Perhaps your container isn't draining and the plants are too wet.  For containers, learn how heavy the container feels when it's wet. Then lift it daily and don't water it until it's light weight...or you can feel the soil and see if it's still damp and if so, don't water.

The other thing to know is to water in the morning, not the evening unless the plants are dead dry at the end of the day. Most plants don't do well with wet foliage and stems all night.

The final thing that can cause brown roots and dying plants is too much fertilizer. If the fertilizer given was too strong, or too much, or given to the plant when it was dry, this causes fertilizer burn. Always apply fertilizer to a well watered plant, and don't mix it too strong.

I hope this helps,
C.L.