Botrytis

• This mold thrives in cool moisture and attacks seedlings. It covers the stems, flowers and leaves with powdery spores, and is easily transmitted from plant to plant through soil and water. Avoid botrytis by avoiding wetting the leaves, flowers and stems of the plants when watering by watering from below the plant.
  
  

Damping Off

• Another fungus that often attacks young petunias is a fungus that is referred to as damping off. This happens to newly germinated seedlings that promptly wilt and die over night. Sanitation is key when preventing this soil fungus. Utilize only sterile containers and sterile seed starter when growing trailing petunias from seed.
  
  

Pests

• Flea beetles sometimes attack trailing petunias, eating small holes in the leaves. White flies may also be attracted, but rarely harm the plant, proving themselves more nuisance than problem. Do not be alarmed by the sticky feel of petunia leaves, as this is a natural occurrence of the plant. Slugs may also attack petunias.
  
  

Drooping

• Petunias often look sickly or droopy after a rain or hard watering, but will perk back up in a few hours. If watering, use the mist setting on your hose to prevent beating them down too severely. They may not bloom on cloudy or overcast days, as the flowers close at night and open during the day when light is good.