Fertilizing and watering in the sedum roof blanket

So by 4pm after an 11am start the 185 square metres of sedum roof is covered and trimmed. Now fertilizer is sprinkled by hand over the roof and the whole roof sprayed with a sprinkler head for an hour or more to avoid the fertilizer burning the sedum. Because of this the initial watering cannot be done using the leaky pipe system but subesquent waterings can. And overnight we get some rain which is a real bonus!