Petunias prefer full Sun. How many hours of direct sunlight are these getting? That last picture shows them in full shade.

I planted .... a few weeks ago.

==>> where are you ... thats pretty late for planting ...i might have planted them.. and put them in full bright shade for a week ... before exposing them to any sun ...

did you immediately put them in sun .... its been very hot for some of us ... and thats never great at planting time ..

did your MG potting soil have fert in it ... thats not good for plants in shock ...

frankly ... transplant shock ... due to large transplants... total root disturbance .... late in the planting cycle ... also.. if you bought them from a greenhouse.. there is a shock there also ....

if you look close.. there is new growth .. that looks just fine.. i suspect.. if you have the patience.. in a 2 or 3 weeks.. you are going to be beating them back with a stick ...

the drainage holes are not an issue... imo ... they arent supposed to be covered ...

ken

Phew! Ok, they get a lot of sun, actually - at least 6-8 hours of direct hot sun. I was afraid that one of the probs was that they were being fried out there (haven't had much luck growing things on that side of the house so I am trying container gardening). Ok, I will keep my fingers crossed. It just looks like something is spreading from that one box to the others. I hope it's saveable! I didn't think about shock. The poor things!

Do I detect a greenish tint to the mix? Is it algae? If so the mix is far too wet. What has your watering scheme been?

@floral_UK - yes, very observant! I saw that this morning when I was investigating, but wasn't sure if that was supposed to be there (??? Never used Miracle Gro potting mix before so had no idea what I was looking at, sorry not an expert gardener here by any means, lol) or if it was something not good. I have only watered it by hand 3 times since I planted them - like once a week, because it has been rainy off and on here in the 3 weeks or so that I planted them. Right now they look too wet for sure. If it is algae, what should I do?

@zen_man - do you think I planted too many in each box? Could that be contributing to the problem? The bugs looked like little flies or fruit flies? I can add more potting mix, but if it is algae on them, I should take care of that first?

Hi momnipotent,

" The bugs looked like little flies or fruit flies? "

Well, if this was indoors I would say the little flies are Fungus Gnats, and it is possible that they are breeding in your potting mix. Their larva are maggots that are clear or white and about 1/4 inch long with a black head. Check your growing medium to see if you can find any small maggots with black heads.

" ...but if it is algae on them, I should take care of that first? "

I grow some zinnias indoors during the Winter and if algae get started in a pot (which is always a possibility) the algae uses up all of the nutrients and the plant dies of starvation. I lost several pots of zinnias to algae before I realized the seriousness of the problem. Now, when algae start to be a problem, I use a product called Physan 20, about 2 teaspoons per gallon in my plant water as an algae preventative. Physan 20 is a multipurpose product, that is used as a disinfectant, sanitizer, deodorizer, fungicide, bactericide, algaecide, and virucide. Many greenhouses use it. I use a lot of it in my indoor zinnia project and some in my outdoors zinnia gardens. I literally buy the stuff by the gallon, and I am on my third gallon now. You could probably get by with the 8-ounce size of Physan 20.

We don't know for sure that the algae is harming your petunias, and we don't know for sure that the fungus gnat maggots are harming them either. Those are just possibilities.

ZM (not associated with any product or vendor mentioned or linked)

Algae really shouldn't be happening outdoors. It is a sign of excess moisture. Stir up the surface of the soil with a fork or something and don't water unless the medium is dry a few inches down. I'd also be tempted to top up those boxes to the brim with dry mix. The petunias won't mind and they'll gave more root space.

I agree with floral_uk. When looking at the photo, I see very wet soil and green on top of the soil. Go with floral's advice. Good luck with your petunias!

I would agree with Floral and Bouquet ... my first thought upon seeing the soil was that it looked like it was kept far too wet. Second thought was in regards to what looked to be a case of them being too heavily shaded until the sunny photo and your mention of how much direct sun they were receiving.

If kept too wet the roots will rot which prevents plants from uptaking water and nutrients. You didn't mention where/what zone you are.

have they started to bounce back??