Some, but only some, of my petunias are turning brown and dying off. This one has a perfectly happy petunia (different variety) growing right next to it.


The same thing is happening in some of my other containers, too. Any thoughts?

Are your containers black or dark colored? Thin plastic, or thick foam?

Are the sick plants on the sunny side of each container? I wonder if the soil is getting too hot for them.

I've had something similar happen before, so I switched to lighter colored, thick foam pots. The sides are at least an inch thick, maybe more.

That might be the culprit in one instance, but the one in the photo is in a half barrel and is actually on the cooler side. You can see there is a perfectly happy one right next to it, and another on the far side of the barrel. And the pansy next to it is fine, too, and they seem to be more sensitive than petunias. Is there some sort of blight that affects petunias?

A fair number of them I believe, but if the top inch or two of your soil has a chance to dry out between waterings/wettings I'd think they weren't the culprits. Is it possible to keep the surface soil dry for awhile and bottom water only? If it is, I'd move it to part-shade and try that (depending on your local conditions, of course). If you're getting regular rains, then maybe not.

If you aren't watering daily - are there any signs of critters digging in it? I had some seedlings that looked rather peaked for a while because a rodent planted sunflower seeds right next to them. If they cover up the hole it's easy to miss the loosened soil. We've had no rain this year, but I still don't water more often than every other day (and usually longer than that), so my disturbed seedling's roots had time to dry out a bit. Damaged, but salvageable.

Actually, I should count my blessings that I have any plants at all this year. Up until the last week or so, it's been all I can do to keep them from rotting from all the water that drenched us. And now all of a sudden we have temperatures in the 90s.
Critters. Hmmmm, could be ants? We are having a problem with them, and I suppose they could easily cause the same sort of problem. I know they killed off a small columbine.

Could be ants...could be the drastic change in conditions, too, especially from super wet to hot. They might have started to blight or rot during the wet and are showing it now due to the stress of the heat. Part-shade, I'd say, and cautious watering. No fertilizer for a while, either.

Well, they can't be moved (BIG containers), but that could very well be what's going on. The one in the photo may make it, but there are two or three others that are probably toast. Not really a big problem because I started way too many and I have some extras that I can use to replace the goners. I shouldn't have this problem next year; I finally came up with a spot to harden off the seedlings where they won't get soaked and end up in standing water if it rains. It was puzzling, tho, because the ones that I'm losing are in all different areas. I'll bet you're right, that they were already compromised and the drastic change was just too much for them. Thanks for giving it some thought, chelle!

I think they got too much moisture and the high heat was just too much for them. I would fertilize them. All your moisture probably depleted the soil mix of most nutrients.

Actually, I tried that, and it didn't seem to make any difference. But what's really weird is that I still have a couple sitting in tiny 4" pots that are doing ok! But as soon as I try to move them into larger pots, they die off!

That is weird

It seems to be only the ones that stayed in small pots for too long and suffered from alternate soggy and dry conditions. Most of the stuff that I planted out earlier is doing just fine, so it has to have something to do with the abuse. Poor babies!
I have some mystery petunias that are doing really well and they're so pretty! Wish I knew what they were so I could buy more. They were supposed to be Hula Hoop Blues, but obviously are not! I thought they were maybe the pink hula hoops, but they're not setting seed, which the blue ones do, so I'm thinking they're something else. Some of them are almost all white and they're ruffled. Very cute.

What are the varieties that are croaking? Some of the petunias that are commercially grown are very sensitive to the pH of water and/or soil. Sometimes the plant get stressed and they stop uptake of nutrients. Temperature and also water temperature also affects the uptake of nutrients.

I think those are Hulahoop

Mostly it's the pale yellow ones that I grew from seeds I harvested off plants I bought last year. And a few of my second generation Sophisticas.

I know, those pink ones do look like Hulahoop, but they are more ruffled than the blue ones and I always get seeds from the blue ones, too. So I'm not sure. I took my paint brush to a few of the blooms I have in a pot out front; maybe I'll get lucky! It would make sense that they're Hulahoop, since the seed packet was for Blue Hulahoops and I did get some of the blue ones. I notice that we don't have Hulahoops in the database. I'd add them, but I'm not sure of the proper botanical name for them.

Some petunias are daylight sensitive too. Varies/series of petunias differ. Mine are OK but putting out less flowers. Our days are definitely getting shorter.
http://assoc.garden.org/course...
Also, sometimes petunias can gain "oomph" by cutting back occasionally.

Karen

The pale yellow petunias are definitely more sensitive to SOMETHING than the other varieties I planted this year! Pity, too, because they're so nice mixed with marigolds and blue lobelia.