are your containers in full sun???

i think you need to riddle back a few more days .. rather than focusing on overnight temps .... stuff just doesnt usually die in hours .... unless it was a FREEZE. as compared to a frost .. but not at the temps you mention ...

btw.. how big are they????

the beat down from the rain might be an option ... but was there any more severe cold in the few days prior ... were the plants outdoors long enough to be hardened off to the 50's temps .. though that isnt very cold otherwise ...

i presume zen will come along.. and give you a better answer.. but in the mean time.. could you post a pic or two??? .. use the camera/photo button below the box you type in to add pix directly to your post ... some of us dont like hitting links ...

ken

who is Zen? a person or a practice. I don't have pics, i'll see if I can get some. as to your questions. Yes in full sun,, when there is some. Size about 3/4 inch. Prior conditions: well temps have been swinging up and down. one night I left them out when the night-time forecast was 39, (about a week-ago), I didn't cover them, and that's the first time I had some die. They turn brown, altho still standing. I wasn't entirely surprised, I figured in spite of the forecast, it must have dipped below freezing. Now that you (Ken) have pointed me to prior conditions, I'm wondering if that night weakened them, even tho ones that didn't obviously die. Since that event, it hasn't been any colder than that, it has been 65 one day and then 55 the next.thanks for your questions. I'll try to come back later with a picture.

Start them indoors 2 weeks before last frost. No problem.

Zinnias like to grow fast, without any growth check...in warm soil. I sow them directly (they are nice big seeds, easy to handle)) around mid May or even as late as 1st week in June. They germinate in as little as 3 days and will be big enough to flower in 6 weeks or so. Like morning glories, there is nothing to be gained from an early sowing...and much to be lost. Struggling, etiolated seedlings rather than sturdy, fast growing plantlets.

looking back, I don't know what happened with the zinnias I posted about. A mystery. But I sowed the rest of the seeds in container and they germinated in a few days - now it is warm. And once in the ground, they are doing great. I also direct sowed some just for comparison. I find the germination rate much better if I sow in the container, altho that does present one additional step.