Should I Start Cool Weather Seeds in a Greenhouse in Zone 9
We have cauliflower, kale, sugar peas, chard, and broccoli.
I suggest planting the seed you mentioned in a greenhouse. Peas are difficult to transsplant, they should be direct sown into the ground. Maybe the kale too, depending on your usual weather patterns. (Here in 6b, we've experienced 68* with sun yesterday, and expecting a high of 35* tomorrow...if 40 mph winds don't blow us away tonight!) Broccoli chard and cauloflower can certainally be grown in cool temps, but I would keep minimum temperatures closer to 45*. Even cool weather plants can be adversely affected by temps too low as young seedlings.