One of the most important factors in hydroponic gardening is the use of a quality hydroponic fertilizer . There are a few main types of these. MR1 grows the fastest, but Metrop MR2 is the most popular. It contains all macro and micro nutrients, including nitrogen, potassium, and phosphorus. It also contains no water or harmful colouring. You should give your plants the same amount each day, regardless of the nutrient content of the soil. The MR2 should be applied daily in poor or nutrient-rich soil, and you can even use it daily in a nutrient-rich soil. It should be stored in a cool, dry place, and out of the reach of children.