Keep in mind when planting that Firecracker is thought of as hardy, so Firecracker will tend to go dormant or grow slowly over the winter months. Ensure your soil has a ph of between 5.1 and 6.0 as Firecracker is a weakly acidic soil loving plant.
By our calculations, you should look at sowing Firecracker about 56 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Firecracker is a hardy plant.