ZM

You mentioned that your zinnias got so tall that they fell over. That sounds like an unhealthy situation. If zinnias don't have enough light, they "stretch" for more light. And if they are too close together, they compete with each other for light and stretch.

Also, July is early for mildew to become a problem. Maybe there is something wrong with your growing conditions. Zinnias require full sun, which usually means at least 8 hours of direct sun exposure per day. Were your zinnias growing in a partly shaded location?

Hi Pat,

" I plant them in a raised bed made up of 5 gallon pots filled with good soil mix and placed next to each other. My bed is about 25 ft. x 15 ft. I planted 3 zinnia plants per pot. "

Where did you get so many 5-gallon pots? I don't know the particulars of 5-gallon pots, but plastic 5-gallon buckets are typically about a foot in diameter, so that bed is roughly equivalent to a Square Foot Garden (SFG), except that you have put three zinnia plants where normally only one would go. So I think those zinnias are suffering from overcrowding. My recommendation would be, next year place only one zinnia per pot.

" The other bed was also in full sun, but next to a small greenhouse. This one did not get good air circulation because of the GH, so they got the mildew in early July.
... Will try tall marigolds in this bed next year, surely they will do better. "

They might. My luck with marigolds has not been so good. I do like their foliage, and I don't mind their odor. But for me, they tend to be "red spider magnets". And since spider mites are spiders, and not insects, insecticides tend to not control them.

Good luck next year.

ZM