Flowering with LED Grow Lights
In nature flowering occurs in the fall, after the long hot days of summer. The long nights and short days of autumn signal the start of flowering. With LED grow lights we mimic the seasons by changing the light cycle from 18 hours a day to 12 hours. Give your plants 12 hours of uninterrupted darkness and 12 hours of light to induce visible signs of flowering in two weeks or less. Adding more light to the plants also help give bigger flowers and yield. It is recommended to add an all red 90 watt led grow light at this stage for more robust flowering. Once you have induced flowering for one to two weeks and flowering starts, it can last can last eight weeks or longer.
During flowering, growth patterns and chemistry changes in the plants. Stems elongate, leaves grow progressively fewer blades and flower formation is rapid at first then slows. Phosphorus and potassim uptake increase to promote floral fomation. Your nutrients should have less nitrogen and more potassium and phosphorus during flowering. Don’t give nutrients too often as this can cause your plant to get nutrient burned. You should use about 30% less nutrients with LED flowering grow lights as compared to MH/HPS systems. Do not overwater and do not harvest too early.
Flowers initially appear near the top of the terminal growth and gradually develop on lower branches starting at the tips and moving downward. Flowers have white pistils which look like hairs. The pistils are attached at the base to an ovule which is contained in a light green pod called a calyx. Pistil packed calyxes form dense clusters along the stems. These clusters are called a top or cola. The calyxes form develop rapidly for the first four weeks after which they grow at a slower rate. Must of the harvest weight is then put on the last two or three weeks of growth when the calyx formation has slowed which is why it is so important to not harvest too early because the majority of your yield comes the last couple weeks. The pistils will continue to swell and change in color from white to amber to reddish brown. Once this occurs you are ready to harvest your plants.