Keep in mind when planting that Mixed Hardy is thought of as hardy, so this plant will survive close to or on freezing temperatures. Mixed Hardy needs a sandy, loamy and clay soil with a ph of 5.6 to 6.0 (weakly acidic soil).
By our calculations, you should look at sowing Mixed Hardy about 105 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Mixed Hardy is a hardy plant.