I only suggested that because they do self seed at the garden and my friend used to have a yardful from self sown seeds and of course, they go through the winter outside. They were beautiful.
Searching cleome germination, I get this
http://higgledygarden.com/2013...
She suggests a week of cold stratification in the fridge, fluctuating temps and light for germination.
Swallowtail says this:
"Plant Cleome Seeds: Sow cleome seed in cell packs or flats press into soil and barely cover. Keep at 75-80°F. during the day, and 10°F. cooler at night. Germination is in 10-21 days. The Queen series cleomes are best sown where they are to grow after all danger of frost ¼ in. deep and 3 in. apart. Thin to 18-24 in. apart.
Grow Cleome: The Sparkler series of cleomes are primed for easy germination and should not be chilled prior to sowing. The Queen series cleomes will germinate at higher rates if the seed is chilled. Spread seed out evenly on a moist paper towel, fold and put inside a zip-lock bag. Place bag in the refrigerator for 2 weeks. Remove seeds and immediately sow into prepared seed beds. For both series high daytime temperatures followed by cooler nighttime temperatures is extremely beneficial. When seed is sown outdoors temperature swings will occur naturally. Indoors, using a heating pad during the day, and turning the pad off at night is highly effective."
So apparently the cold period is short enough that you could plant in the spring.
