Medpot Minstrel: Hydroponics Medical Marijuana

Friday, March 16, 2007


Macro and Micro Nutrients, Deficiencies, Overdose

Whenever the appearance of some leaves changes, the first thing that comes to mind is nutrient deficiency. Either that, or too much of a certain nutrient. But before I jump to such conclusions, I always make sure that all the other variables are under control.

Each of the vital ingredients that contribute to healthy cannabis plants has to be checked, in order to narrow down the cause of a leaf’s yellowing, for instance. Is there sufficient air (ventilation), light, and water to maintain the balance required for photosynthesis?

Are the temperature, humidity, and CO2 levels within the desirable range? Before nutrient deficiency or excess can be determined, you have to look at the recent history of the plants. Has anything stressful or potentially stressful happened in the last couple of days?

I’m about to make the final gender selection and switch my six ladies to a 12 hours light, 12 hours darkness regimen. Yes, it’s time for them to start building flowers. I will give them Bud Blood during the first week of flowering, then Big Bud for weeks two, three, and four, followed by Overdrive for weeks five and six.

Bud Blood will help the plant along the natural course of bud formation. Big Bud will contribute the building blocks of bud growth, while Overdrive will accelerate that growth. Sort of like putting gasoline with an additive in your car’s gas tank, then stepping on the gas pedal.

Nutrients are elements that plants need to thrive. Hydrogen, Oxygen, and Carbon are obtained from water and air. Normal air has 300 ppm of carbon dioxide in it without any CO2 generation.

Nutrients are divided into macronutrients (Nitrogen, Phosphorus, and Potassium) and micronutrients (Magnesium, Zinc, Boron, Calcium, Cobalt, Copper, Iron, Manganese, Molybdenum, Selenium, Silicon, Sulphur, and Chlorine).

The macro ones are needed by the plant in relatively large quantities, while the micro ones are only needed in trace amounts.

Another way that Nutrients are divided are into Mobile and Immobile Nutrients. Nitrogen, Phosphorus, Potassium, Magnesium, and Zinc are Mobile, all the others are Immobile.

Mobile Nutrients move to the parts of the plant where they are needed. Older leaves show deficiencies of these Nutrients first.

Immobile Nutrients stay in the place within a plant where they are originally deposited. Young shoots and leaves show deficiencies of these Nutrients, before older leaves.

Macronutrients show up as the NPK number on the packaging of each fertilizer. Sensi Grow A & B, for instance—my base fert—has an NPK of 5-2-6, which means that it contains 5% Nitrogen, 2% Phosphorus, and 6% Potassium.

Sensi Bloom A & B has an NPK of 5-4-8, which accounts for the fact that during the flowering stage plants need more Phosphorus and Potassium. In addition, this cannabis specific 2-part has all the micronutrients that my ladies need, in easily absorbable form.

Grandma Enggy’s Seaweed Extract has an NPK of 1.5-1.5-1.5, which means that it has 1.5% of each of the major macronutrients.

Marijuana requires large amounts of Nitrogen during vegetative growth and less of a percentage of Nitrogen in relation to Phosphorus and Potassium, during the bloom phase.

In order to figure out the exact percentage of macronutrients that your plants receive, you not only have to take into account the NPK of your base fert, but also the NPK’s of all your supplements.

For instance, during this coming week I’m mixing Sensi One Bloom A & B and Bud Blood. Bud Blood has an NPK of 0-39-25, so when I add that to the NPK of my base fert, I wind up with a total NPK of 5-43-33. I only add Bud Blood for one week, in order to help trigger flowering.

This means that for one week a full 43% of my nutrient solution will be composed of Phosphorus, with 33% Potassium. Nitrogen will stay at the 5% level.

Big Bud has a much more modest level of P and K (0-1-4) but it still changes the ratio of P and K to N. Overdrive has an NPK of 1-3-4.

All the ingredients of my nutrient mix have to be taken into account when figuring my total NPK ratio. B-52, for instance, has an NPK of 2-1-4. Mother Earth Super Tea Bloom, which I like to add to the mix for that organic touch, has an NPK of .50-1.50-2.0.

Composed of alfalfa extract, canola meal, citric acid, crab meal, earthworm castings, fish meal, sea kelp, and shrimp meal, Mother Earth Super Tea Bloom was designed to give my cannabis ladies natural supplements, nutrients, and vitamins—i.e. organic ingredients—that are missing from synthetic fertilizers.

Nitrogen helps my ladies to make proteins that are essential for new protoplasm in the cells. That’s why a bigger relative percentage is needed during vegetative growth. It is utilized in the production of amino acids, enzymes, nucleic acids, chlorophyll, and alkaloids.

Leaf and stem growth depend on Nitrogen and the overall size and vigor of each cannabis plant depends on the availability of this macronutrient. It is not only active during the formation of young shoots and leaves, but also while young buds are being formed.

Nitrogen comes in Ammoniacal form (too much of this can burn your plants) or in the more common form of Nitrates. This latter form is much slower to assimilate than the Ammoniacal kind.

The most common nutrient deficiency is Nitrogen deficiency. Symptoms are a lower growth rate, lower leaves which are unable to produce chlorophyll turn yellow between the veins, while the veins stay green. Eventually, the entire leaf becomes yellow and dies.

Stems and leaf undersides may turn reddish purple. This symptom could also mean Phosphorus deficiency. Nitrogen is a very Mobile nutrient, it must be added regularly to fast growing gardens, otherwise it dissipates into the environment.

An overdose of Nitrogen will result in excessively lush foliage that lacks hardness and hardiness. It is vulnerable to insect attacks and fungal infestations. Stems are weak and may fold easily. The plants are unable to uptake water.

Allowed to go untreated, a Nitrogen overdose may result in leaves turning brown, drying, and falling off. It also results in roots growing very slowly, turning a dark color, and rotting.

If you’re growing in hydro, Nitrogen overdose can be treated by flushing your system with pure water for one week giving the plants a chance to use up the excess Nitrogen in their leaves. If symptoms persist, cut back on the amount of the Nitrogen that you add to the nutrient mix.

Phosphorus is essential for photosynthesis and aids energy transfer within the plant. This macronutrient is involved in maintaining overall vigor, as well as resin and seed production.

Phosphorus deficiency is indicated by stunted growth, and bluish-green leaves, often with blotches.

Reddish purple stems and leaf undersides may also result. Large black blotches appear on severely affected leaves and they end up dropping off. Flowering happens much slower and buds are generally smaller. These plants are susceptible to insect and fungal attacks.

Potassium is utilized by the plant in the manufacture of sugars and starches. Growth by cell division is affected by Potassium. Chlorophyll production is enhanced and stomata openings are regulated by this macronutrient.

Signs of Potassium deficiency are older leaf tips then leaves turning dark yellow and dying. Stems become brittle. Disease often follows.

By using a synthetic or organic fertilizer from Advanced Nutrients, along with the suggested supplements, root colonizers, and bloom boosters, you can be sure that you’re feeding your cannabis plants the optimum levels of all macro and micronutrients, so you don’t have to worry about deficiencies or overdosing.

posted by Wes @ 4:31 PM

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