Planting sweet peas in autumn may seem counterintuitive, but it is the best way to get a head start and ensure success if you live in an area that experiences hot summers. Sweet peas hate the heat and quickly peter out when temperatures are in the 90’s and above. Growing sweet peas in autumn gets your plants way ahead of the game and blooming in early spring before that darned heat arrives! Please remember, all parts of the sweet pea plant are toxic.