Planting out bedding plants?

[Bluntness100]

I bought a couple of trays of petunias at the weekend, as I had huge success with them last year. However I bought them later in the year and more mature.

These are much smaller, although some flowering, and the garden centre had them indoors.

And now I'm a bit unsure what to do. When should I plant them outside please, they are for containers and hanging baskets, and do I need to do anything to make them hardy?

Right now I have put the trays in the green house, but am slightly unsure on what to do next, as don't want to kill them.

Any advice would be great, thank you.

Wait until Mid May. There could still be frosty nights. Meanwhile, on sunny days put them out to harden off, but bring them in later in the afternoon.
When you put them out, place them in an elevated position so that slugs and snails can’t get at them.

Ok, I will do and thank you, that's very helpful.