Cannabis seedlings get most of the nutrients they need from the seed while absorbing water through their first leaves as the root system develops, which is why it is important to grow them in a warm, humid environment. You will not have to start feeding cannabis seedlings until they reach about 2 to 4 weeks old and have developed a few true leaves, entering the vegetative stage. We recommend a mild nutrient solution such as Clonex.
Cannabis plants require macronutrients which are nitrogen (N), phosphorus (P), and potassium (K), which are typically listed on fertilizer products as an NPK ratio. Cannabis plants also require secondary nutrients including calcium, magnesium, and sulfur for plant health and growth. Additional micronutrients include manganese, zinc, molybdenum, iron, copper, chlorine and boron. We recommend Greene Aminos from GreenGro Biologicals. Fertilizer products can vary greatly with the ingredients used to achieve their NPK ratio, ranging from highly chemical to natural, organic products.
Some growers prefer to start their plants off on a 2:1:2 ratio early in the vegetative growth phase which can introduce your plants to fertilizer without causing chemical burn. Others start with a higher ratio of 4:2:3 to jumpstart growth and see great results.
By mid-vegetative stage, you can get more aggressive with a mix closer to 10:5:7, with a heightened nitrogen level helping your plants to produce green, luscious foliage and bud sites. You’ll want to reduce this to something closer to a 7:7:7 ration during the last week of the vegetative stage. With some TLC and attention to your plant’s needs, you will learn what ratio and fertilizer works best for your cannabis crop.