Keep in mind when planting that Sidborough Poppet is thought of as hardy, so Sidborough Poppet will tend to go dormant or grow slowly over the winter months.
By our calculations, you should look at sowing Sidborough Poppet about 90 days before your last frost date.
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Sidborough Poppet is a hardy plant.