Posted: 18/10/2013 at 15:26
I grow autumn sown sweetpea every year and have done for years. I leave them outside all winter long, let most of them germinate outside and never see the inside of a growhouse or coldframe. Mine grow below the windowledge or on the windowledge where the rain that we have so much of, does'nt tend to flood them.
They can easily withstand frosts although not prolonged frosts. I've only ever lost them once and that was the year the frost lasted for 3 weeks or so at one time. I lost them then because I was away from home and they could'nt thaw out enough to water.
In my humble opinion sweetpea sown in autumn make much stronger and healthier plants than those sown in late winter or early spring, although I do sow then as well to prolong the season and just because I can.