Re the Geraniums. They will not do at all in a shed with no windows. I find they root well when Close to the glass so you will need to put them on your window sill indoors. This you could do now, they will root & grow on through the winter.
Poppies are usually sown direct into the ground where they are to flower & then thinned out( that's if you mean annual poppies). Not sure about the oriental ones & the delphiniums. Do you mean to plant outside, or put into a bigger pot & place in a cold frame or greenhouse?

I take my Geranium cuttings in the spring as their survival rate is better then.

when you say geraniums do you mean the summer bedding ones actually pelargoniums?
I have done many over the years. some plants have been lifted and kept barely dry in an unheated but frost free conservatory. then I took cuttings in the early summer.
other times I have taken cuttings now rooted and potted them on and kept frost free and although green they don't do much growing as they are too cool.

What do you mean by planting poppy seeds on? Did you grow seedlings in a pot?
Usually poppy seed should just be scattered on broken soil in about March or later.
The reason that poppies are commemorative of WW1 is that the agricultural fields of France were utterly smashed by artillery & then the first thing that re-grew in the churned up soil was blood red poppies

Hi, I grew Dwlphiniums from seed the 1st time this year. They are known to be difficult to germinate. My 1st 2 times failed and so I did a bit more research into it. I had a bowl of only slightly warm water, placed seeds in that and left to soak overnight. Then I sewed then into a seed tray of seed compost, covering them lightly with compost. I sprayed the compost until fairly damp. I then covered seed tray in kitchen foil and put in a warm place. This was done in February. This gave me the highest germination rate. Good luck 😀

Wow so much help guys thanks very much I’m going to scatter the poppies in March, and as for the delphiniums I’m going to try so wish me luck, Geraniums will try to grow them indoors then take them out next year. I don’t have a greenhouse or conservatory but I do have a very large floor to ceiling window. So thanks everyone for your generous help.

With the delphinium, I bought 2 sorts. One said was giant and one that was dwarf. The dwarf ones was a lot easier to germinate. As said with the giant ones, 1st two packets didn't germinate and the 3rd try, I got about 40 ish to grow. I kept an eye on the 3rd lot, making sure the compost was still damp but kept the foil cover till I saw that had seedlings growing. This gardening thing is learning all the time lol. 😀 Jen