Yes, you will need to use plant nutrients when growing organically to get the most out of your plants, however using more nutrients does not mean more growth. You can make many errors such as over-feeding your plants. Make sure you refer to the British Organic Bio nutrient schedule to make sure you feed your crops correctly.
What substrate should I use when growing organically?
There are various types of substrates to use when growing indoors, however when growing organically the best substrate to use is an all-mix substrate as it contains mixed types of peat. BOB Organic All-mix is perfect for this, as it is pre-fertilised & activated using organic materials.