the petunas have beautiful flowers but soon they become slimey and "melt"
Unfortunately, your photo did not come through. It does sound like something bacterial, though.
This article will help you with bactericide use:
https://www.gardeningknowhow.com/garden-how-to/info/applying-bactericide-to-plants.htm
This article will help with fungicide use:
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
They will start forming seed after in bloom for a while. Cut the plants back by about 1/3 and give them a slow release fertilizer like a 10-10-10.
https://www.gardeningknowhow.com/ornamental/flowers/petunia/deadheading-petunias.htm
https://www.gardeningknowhow.com/ornamental/flowers/petunia/petunia-care.htm
will the petunias grow back?
Yes. Cut them back by at least 1/3 of their length so you are sure to cut off the seedheads forming. The seedheads will shut off the flowers. By shearing them back, they will return quickly to bloom again. Also give them a slow release fertilizer if you haven't fertilized recently, such as a 10-10-10.
https://www.gardeningknowhow.com/ornamental/flowers/petunia/petunia-care.htm
https://www.gardeningknowhow.com/ornamental/flowers/petunia/deadheading-petunias.htm
Is this a virus or something that i should throw away so i can keep my other plants safely? Please tell me what should i do with it and why it can happen to my plant. Sincerely,thanks.
Likely, it is due to being planted in clay soil. This type of soil is too heavy, and retains too much moisture to support Petunias. They are very sensitive to infection, so well draining potting mix will be necessary to keep these plants alive.
This article will help you to care for Petunias:
https://www.gardeningknowhow.com/ornamental/flowers/petunia/petunia-care.htm
I live in Brisbane Australia. I would love to put some flowering plantars under my windows facing south. I'm considering a trough container garden w superbells, petunias, lobelia and silver falls. It's very sunny in this area (despite facing south). However, given the eaves, it will probably not be direct sunlight. Is that a no go? Thanks
I would try it and see how they do the first year. If flowering is diminished, the next year you can try shade plants. Here is more:
https://www.gardeningknowhow.com/special/shade/shade-tolerant-flowers.htm
I was wondering because I am late to cleaning up planters, but if they can be overwintered, I won't throw them out. But if they can't be overwintered, I need to dump them out quick - warm today, but cold later in the week. The patio is near the house.
No. They are annuals, and will have to be grown from seed next year. The good news is that it has likely seeded, already. This will mean that you will probably see new plants coming up next year, whether it be in the same container, or near where the container was.
Here is an article that will help you with the care of Petunias:
https://www.gardeningknowhow.com/ornamental/flowers/petunia/petunia-care.htm
This is my first season working in a greenhouse, I have a lot to learn, I have just repotted and planted annuals from plugs into quarts and some into hanging baskets. How often should they be trimmed, I know you need to do some to get them nice and full, also how often should they be fertilized. The plants are Petunias, Geraniums, Lantana, Cali's, Impatient, Bacopa, the more common annuals.
It would be difficult to give a timetable because growth depends on a lot of factors. However, as the stems begin growing beyond the container, start pinching them back 1/2 an inch to an inch. As they get fuller, continue to pinch the growing tips so they will branch. You will get a feel for it, the more you do it, and how often.
If you use an all purpose time-release granular fertilizer like 10-10-10, you can fertilize once every two months.
https://www.gardeningknowhow.com/garden-how-to/info/pinching-plant.htm