Keep in mind when planting that Sultan Red and Yellow is thought of as very hardy, so this plant will tend to go dormant over the long winter months. Ideally plant in loamy soil and try to keep the ph of your soil between the range of 6.0 and 7.0 as Sultan Red and Yellow likes to be in weakly acidic soil to neutral soil.
By our calculations, you should look at sowing Sultan Red and Yellow about 56 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Sultan Red and Yellow is a very hardy plant.