Posted: 05/04/2013 at 10:02
Provide some support in the form of sticks for your sweetpeas and sunflowers, they sound ok.
Sweetspeas do benefit from a pinch but I've never pinched sunflowers, as most grow on one stem. Unless you have a bush variety, of course.
I am not aware of any "rule of thumb" with regards to pinching. I just learnt how to grow and treat my plants through practice, trial and error and lots and lots of reading - RHS encyclopedia was of some help, as was other reading material.
If your seeds are still in the seed leaf stage, 2-3 inches and are floppy. That is usually an indication that not enough light has been provided and their have put all the energy into searching. Often, this kind of syptom does not make for strong plants.