Nutrient Guide For A Flowering Cannabis Plant
I have went over this in the nutrient guide for a vegetative cannabis plant, however for anyone who hasn’t read that I will give you a brief overview of the nutrients your cannabis plant will require to thrive. The main three nutrients are nitrogen (N), phosphorous (P) and potassium (K) and they will be denoted by the NPK formula on the side of your nutrient bottle. Secondary nutrients are Calcium, Sulphur and Magnesium. In trace quantities, boron, copper, molybdenum, zinc, iron, and manganese.
If feeding by hand and using dry nutrients, mix them the day before in very hot water to dissolve and let cool overnight. If using tap water, leave the top off to evaporate some of the chlorine. If using premixed liquid nutrients then skip this step. Most hydroponic solutions should be in the range of 150-600 parts per million in dissolved solids. 300-400 ppm is optimum. It is possible to test your solution or soil with a electrical conductivity meter if your unsure of what your giving your plants.
Keep in mind most dissolved solids readings are usually on the low side, and actual nutrient levels are usually higher. It is possible with passive hydroponics, to get nutrient build-up over several feedings, to the point the medium is over saturated in nutrients. Just feed straight water now and again, until you notice the plants are not as green (slightly), then resume normal feeding.
Your plant will still need all of the same nutrients that you were giving it in the vegetative stage, however the ratios will differ greatly. When flowering your plants will require higher amounts of phosphorous and potassium instead of the nitrogen heavy feed you gave them early on in the vegetative stage. Any fertilizer that is labelled bloom will be beneficial for your plant during the flowering stage. By lowering the amount of nitrogen that you are feeding your plants you will ensure that the plant in question does not waste energy producing more leaves, the increases levels of potassium and phosphorous will ensure your cannabis plant has thick colas and flowers.
In the latter phase of flowering (approx week 10-13) your buds will start to pack on mass as vertical growth slows dramatically. Marijuana can be very fussy so be very aware of any clues she gives as to nutrient deficiencies. A sure-sign of ‘nute-burn’ or overfeeding is the appearance of brown leaf tips anytime during the nutrient cycle. In the next few weeks the bottom leaves of the cannabis plant will start to turn yellow in color. This is normal and not a sign of a nutrient deficiency. Rather than processing new minerals through the roots, the plant saves energy for budding by feeding on itself. You should reduce feeding at this time from half to 25% of normal. Once the pistils turn rust-colored and the trichomes start changing from clear to milky it is time to stop feeding altogether and only give your girls pure water. This will flush your plants of any excess nutrients and give you a cleaner smoke.