Does anyone have any tips on how to press dry sweet peas?
To be honest, I would not bother to try it as the petals are too delicate for pressing, they will detach from the stem and if you mean drying for floral decoration, they will simply continue to develop a pod and shed the petals.
The old way was to dry any flower betweent the pages of a book.
Some guides recomend drying delicate flowers in a vase of sand/borax or silica completely covering them and entirely dry kept in a dry warmish place. Put wire around the stems before you put them in
You'd have to be really careful when you removed the sand but might be worth a try, Some also recomend giveing them a last drink with glycerine in it which in some way fortifys them one part Gylc to two parts water.
But they are so delicate that you might get one in ten survive intact.
hope that helps
x sunloving