Keep in mind when planting that Rocket Mix is thought of as very hardy, so this plant will tend to survive through freezing conditions. Rocket Mix needs a loamy soil with a ph of 6.0 to 7.0 (weakly acidic soil to neutral soil).
By our calculations, you should look at sowing Rocket Mix about 56 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Rocket Mix is a very hardy plant.