Do my autoflowering weed seeds need additional nutrients? I was told by the company that sold them to me that nutrients aren't required, but from my 20 years of experience, I don’t see how they don’t need nutrients. I will be eagerly waiting any advice.

By August Dunning | Last updated: December 17, 2021

flowering cannabis

Autoflowering cannabis is the third type of cannabis (Ruderalis genetics) that evolved originally in short summer locations. Autoflowering cannabis doesn’t have a photoperiod sensitivity so it will flower about 15-22 days after germination and, depending on the variety, harvest is between 50 -100 days. Because it has this significantly different life cycle, fertilization is different as well. So, you must load inputs to get top performance and yield. Micronutrient minerals are essential for rapid root expansion, so the following growth has the means of absorbing nutrients. Minerals are necessary to balance the N-P-K inputs, so having them in the growing medium is essential for maximum growth stimulation. You can also add beneficial microbes. The microbes make the micronutrient minerals more available for absorption and together cause massive root branching and strong top growth. And it’s probably a good idea to use a B-vitamin like Organic B or B-52 all along the cycle to keep stress and fertilizer shock to a minimum since you are pushing the plants for maximum yield.

Growth: First off don’t transplant them, there’s no time to waste on transplant shock so just germinate them in the medium they will be harvested in. A good container is the 420 one-gallon grow bag on Amazon for great oxygen delivery to the roots for a huge root ball to pump nutrients into buds that works with the short grow cycle. Keep the light soft at the beginning with T-5 high-output fluorescent and switch to LED or HID in a week after the first leaves come out and raise them as the plants grow. And don’t have the light too close to the plant tops. If the leaves curl, it’s too close. They need at least 18 hours of strong light with a full spectrum in veg and bloom so choose illumination based on day-spectrum charts. A combination of metal halide and high pressure sodium is an easy fix to this requirement. Autoflowering cannabis only gets to about 48 inches tall, so LEDs provide great light as well from start to finish. Back off the red-light frequencies in sodium for the last 48 hours before you harvest to max out THC and terpene production.

Fertilization: Nutrient application is started slowly in the first week (like half strength). At two weeks start using potassium silicate for structure growth that will support large calyx growth. Thereafter ramp up the feeding during the first two to three weeks using a pH-balancing formula. At the first sign of flowers do a small flush with reverse osmosis or distilled water, then switch to a high-yield simulator. Add a bloom booster to max out your calyx formation.

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Propagation Seeds Plant Nutrition Plant Growth Cannabis

Written by August Dunning

Profile Picture of August Dunning

August Dunning is the CEO of Eco Organics and is a physicist, chemist and an inventor. He is the former systems ops designer for the International Space Station and a former regional manager of liquid, solid and electric propulsion systems for Pratt and Whitney space propulsion, Edwards AFB, NAWC and JPL.

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