You don’t need to add anything initially when potting up or planting out, but because Coco Grow and Coco Grow+ don’t contain any plant nutrients, you will need to add a fertiliser when the plants are actively growing; for the vast majority of plants this is from early spring to early autumn. Coco Grow Boost does contain a N:P:K fertiliser that lasts for up to six months. You will need to add plant nutrients and feed after this time.