Nearly all cut flower and bedding plant growers plant zinnias. Many growers observe losses in crop quality due to leaf spot diseases. This project entailed seed treatment trials to study source of inoculum and efficacy trials of disease suppressive microbials and compost in greenhouses and cut flower fields. Clorox at 20% for 20 minutes reduced viable bacteria on seeds to zero; hot water treatments 52°C for 20 minutes reduced the presence of fungi. Both treatments affected seed germination rate, but at an acceptable level. The cut flower growers observed an increase in plant quality when seeds were grown in BioComp compost instead of standard peat/lite mixes. Disease suppression was observed with the variety Ruffles treated with the microbial inoculants Mycostop, RootShield, and SoilGard. The results in identifying effective seed treatments and disease suppressive inoculants are very promising, but need to be repeated before making firm conclusions.