Keep in mind when planting that Plume Mix is thought of as tender, so it is really important to plant out well after your last frost date. Try to keep the ph of your soil between the range of 6.1 and 7.5 as Plume Mix likes to be in weakly acidic soil - weakly alkaline soil.
By our calculations, you should look at sowing Plume Mix about 49 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Plume Mix is a tender plant.