No I do not add any other fertiliser as blood , fish and bone is a slow release fertiliser and suffices for the season. I keep them well watered and only make one sowing. I will be harvesting carrots from July until Christmas the early ones are frozen whole as I think that there is nothing worse than having carrots on my plate that have been chopped into slices.Thanks Plot22. Awesome feedback!! Nice photo too! So you add blood, fish, bone as a granule to the soil 1 week prior to seeding...and do you add anymore fertilizer at a later point? Do you do plant one group early spring and another group in summer to get 2 harvests ?