Pleasewould somebody explain growing sweet peas to me?

[WellTidy]

I would like to grow sweet peas this year. I had the idea of growing them in a long multi purpose compost bag or two, and putting the bag in some sort of wooden trough on my patio, against a wall, and growing the sweet peas in there.

I see adverts this this for sweet peas and think that is just what I am looking for, but when they arrive, would I be able to just put them straight outside in the gro bag? I don't want to grow things on indoors, and I don't have a cold frame or greenhouse or anything. Everything I buy, I need to be able to directly plant into the soil.

So - if I can't buy the sweet peas above, how do I buy them?!

Wait until the last frost has passed and then buy them as plug plants. They can be bought quite cheaply from garden centres or somewhere like Parker’s online. Thompson and Morgan are quite expensive for basic plants you can buy a lot cheaper elsewhere.
These mini plugs sold at the moment won’t survive outside yet and are meant for growing on in a greenhouse but a lot of people think just because they are in the garden centre now they are ready to go out. They buy and plant only to find the frost gets them and they have to buy again. I think the go do it deliberately to generate extra sales.

Fantastic, thank you (again) Cant. I will definitely wait and try Parkers in early May.