Nutrients – “Turps notes version”
To have a successful harvest, plants require a specific diet the same way an athlete requires a protein rich diet. Providing your plants with the right nutrients is key to having a successful harvest. There are two ways of doing this: 1. Organic 2. Synthetic (salt based formulas). This process is where new growers can become overwhelmed trying to make the right decision with so many options available. So, we are going to try and break it down for you guys giving the “Coles notes” version rather than the lengthy chapters from respected grow guides.
There are three main categories of nutrients; Macro-nutrients (Primary nutrients) Secondary nutrients and Micronutrients (trace elements) Each of these can be further classified into mobile or immobile nutrients. Mobile nutrients are your Nitrogen, Phosphorus, Potassium, Magnesium, and Zinc. What makes these mobile is they can translocate from one section of the plant to another. For example: Excess nitrogen accumulated in older leaves can translocate to younger leaves which may be suffering a deficiency. This results in deficiency symptoms appearing on the older lower leaves first. Your immobile nutrients are Calcium, Boron, Chlorine, Cobalt, Copper, Iron, Manganese, Molybdenum, Silicon, and Sulfur which do not translocate to new growing areas instead remaining in their original place. An immobile nutrient deficiency will show symptoms in the newer leaves at the top of the plant.
These are the nutrients the plant uses the most. Fertilizers usually show the NPK ratios in big numbers on the front of the package and always listed in the order N-P-K. These nutrients must always be in available form providing the building blocks for rapid growth.
Nitrogen (N) – (mobile macro nutrient)
During the vegetative phase, your plants require more nitrogen, while during flower less nitrogen is required. It is especially important to keep your nitrogen levels in check during flower. Elevated levels of nitrogen especially in the beginning stages of flower can actually trigger hermaphroditism in plants which are prone. Nitrogen is responsible for your plants ability to create essential proteins. This plays a key role in tying proteins, hormones, chlorophyll, vitamins, and enzymes together. It is essential in the production of amino acids, enzymes, nucleic acids, chlorophyll, and alkaloids. Nitrogen’s main function is responsible for the growth of leaves and stems, as well as impacting size and vigor.
How to identify a nitrogen deficiency:
• Slowed growth
• Early stages of deficiency leaves will start to turn yellow between the veins. While the veins remain green
• Later stages the yellowing progresses through the entire leaf eventually causing it to die and drop off
How to treat nitrogen deficiency:
• For Synthetic(salt) growers use a high nitrogen fertilizer, or a complete NPK fertilizer. (Within 4-5 days you should see health and vigor returning)
• For Organic growers use a fast-acting source such as Guano, Fish emulsion, or blood meal.
• Nitrogen fixing bacteria (this will help your plants uptake the appropriate amount of nitrogen, and even help reverse and overdose)
How to identify nitrogen toxicity – Signs to look for a nitrogen toxicity include dark foliage and down curling of the tips of your leaves. This can cause your foliage to turn soft which leaves it vulnerable to insect and fungal attacks. Stems may become weak and fold easily. In severe cases leaves will turn a brownish copper color, become dry and fall off.
How to treat Nitrogen toxicity:
• Flushing the growing medium with PH corrected water with 3x the volume of water to growing medium letting the over flow drain. You can use a PPM or EC meter to watch the levels decline to where they should be depending on stage of growth
• Flushing with PH correcting water and nitrogen fixing bacteria
Phosphorus (P) – (mobile macronutrient)
The most amount of phosphorus used during seedling germination, cloning, and flowering.
Phosphorus is important for photo synthesis providing a mechanism for the energy to transfer within the plant, not only that but it is also associated with overall vigor, resin, and seed production.
How to identify phosphorous Deficiency:
• Stunted growth/ slow growing plants
• Smaller leaves
• Leaves turning blueish green
• Under side of stems and main veins turn reddish purple (this is not always visible)
• Leaf tips of older leaves turn dark and curl downward (in serious cases leaves develop large purplish- black necrotic blotches)
• Leaves will evolve to a bronzish purple, become dry, shrivelled, contorted, and drop off.
• Delay in flowering
• Buds are noticeably smaller
• Plants may become infected with a fungal disease or insect infestation due to because they are weak which will increase vulnerability
How to treat phosphorous deficiency:
• It is always easier to prevent a deficiency then correct one (this goes for all nutrients). A few things you can do to prevent this are: making sure your soil isn’t soggy or acidic by ensuring proper drainage and keeping the soil PH between 5.5-6.5 also keeping iron and zinc levels in check.
Synthetic(salts) growers – water with a compete NPK fertilizer
Organic growers – bat guano, steamed bone meal, natural phosphates, or barnyard manure to increase phosphorus levels. Always make sure to use finely ground organic components.
How to identify phosphorus toxicity – Phosphorus may take a few weeks to show signs of toxicity. Cannabis uses a lot of phosphorus during its life and most cultivars can tolerate high levels. However, excess interferes with the stability and uptake of calcium, copper, iron, magnesium, and zinc.
How to treat Phosphorus toxicity
• Flushing the growing medium, a minimum of three times the volume of water to volume of growing medium
Potassium (K) (mobile macro nutrient)
All stages of growth require potassium. High levels of potassium are associated with a high resistance to bacteria and mold, and an increase in combining sugars, starches, and carbs. This is essential to their production and movement. It increases chlorophyll in the foliage helping regulate the stomata openings which helps plants by aiding in photosynthesis, and absorbing nutrients through foliar feeding. Having a sufficient source of potassium is essential for carbohydrates to accumulate and be translocated. It is responsible in making the proteins that augment the oil content improving flavour in your cannabis, encourages strong root growth which increases disease resistance and the amount of water intake.
How to identify potassium deficiency:
• It takes awhile to show signs
• Plants may develop spots
• Turn dark yellow and even die
• Stems become brittle
• Signs of burning on the edges of leaves
• Leaves turn gray, and progress to a rusty brown color and eventually die
• Older leaves yellow with rust color blotches
How to treat potassium deficiency:
• Synthetic(salt) growers can use a complete NPK fertilizer, or add pure potassium powder and PH correct the water
• Organic growers can add potassium in the form of soluble potash (wood ashes) mixed with water (when using wood ash be sure to check the PH as it can raise above 10, correct it to around 6.5 before feeding)
Hot to identify potassium toxicity –
Potassium toxicity will appear with symptoms of magnesium, manganese, zinc, and iron deficiencies.
How to treat potassium toxicity:
• Flush growing medium with a min of three times the volume water to three times growing medium
Secondary nutrients (trace elements)
Secondary nutrients such as magnesium, calcium and sulfur are also used by the plants in large amounts. Vigorously growing plants can process more secondary nutrients than most general-purpose fertilizers supply. Therefore, growers choose to use high quality two- or three-part hydroponic fertilizers to supply all necessary secondary nutrients. Reverse osmosis water is void of these nutrients while tap water can contain an abundance. When growing in a soil/soilless (peatmoss, coco, etc.) medium with a PH below 7. Use one cup of dolomite lime per gallon of medium. This will ensure there is a sufficient level of calcium and magnesium in your medium.
Magnesium (mobile secondary nutrient)
Magnesium is especially essential in the production of cannabis. Deficiencies are especially common in acidic soils (below PH of 7) adding dolomite limes to acidic soils before planting will help stabilize the PH as well as add magnesium and calcium. Epson salts can be added to correct magnesium deficiencies if no dolomite was used when planting. Magnesium is essential in the process of photosynthesis. It helps enzymes make carbohydrates and sugars that are later transformed into flowers. It also neutralizes the soil acids and toxic compounds produced by the plant.
How to identify magnesium deficiency:
• No signs for first 3 to 4 weeks
• More common indoors vs outdoors
• During the 4th to 6th week lower leaves and the middle leaves develop yellowy patches while the veins remain dark green
• 6th week + Yellowy patches turn into rusty brown spots
• Within a few weeks the entire plant could become discoloured
• If this prolongs the plant will start to turn yellowish-white and then die
How to treat magnesium deficiency
• Synthetic (salt) growers feed cal mag (read label on bottle for required amount) It may vary depending on brand
• Organic growers treat by watering with two teaspoons of Epson salts (magnesium sulfate) per gallon of water. for fast results give a foliar feeding with a 2% solution of Epson salt
How to identify magnesium toxicity
• This is extremely rare, almost unheard of (according to our credible books)
Calcium (immobile secondary nutrient)
A Similar ratio of calcium to other macro nutrients is required while growing cannabis. The production and growth of cells requires a good amount of calcium. Its primary purpose is to preserve membrane permeability and cell integrity, which guarantees a consistent flow of nitrogen and sugars. This simulates enzymes that help build strong cell and root walls. The growing tip of each root must contain calcium.
How to identify calcium deficiency
This is very uncommon except unless the grower is using reverse osmosis water and is not supplementing with a cal mag product.
How to identify calcium deficiency:
• Weak stems
• Very dark green foliage
• Exceptionally slow growth
• Young leaves are the first to show signs
• Severe calcium deficiency causes new growth to turn yellowish purple before shrivelling up and dying
• Bud development is inhibited
• Plants are stunted
• Harvest is diminished
How to treat calcium deficiency:
• Synthetic (salt) growers use the required amount of a cal mag supplement depending on brand
• Organic growers dissolve ½ teaspoon of hydrated lime per gallon of water. Keep watering until the symptoms disappear
Hot to identify calcium toxicity
• Potassium, magnesium, manganese, and iron deficiencies may present themselves
• Stunted growth
How to treat calcium toxicity
• Flush with a minimum of 3x the volume of water to the volume of growing medium
Sulfur (immobile secondary nutrient)
Sulfur is essential in the production of many hormones and vitamins. Sulfur is responsible for protein synthesis and the forming of the amino acids cysteine and thiamin (vit B) which are the building blocks of proteins. Oils and flavours rely on sulfur for their production as well as the synthesis and breakdown of fatty acids.
I am sure you have been told when measuring out your liquid nutrients “be sure to rinse out the measuring container in between bottles!!” This is because sulfur and calcium cannot be combined in a concentrated form or it will create crude insoluble gypsum (calcium sulfate) and end up as a residue on the bottom of the tank, which is why most bottled nutrients come in 2-3 part kits.
How to identify a sulfur deficiency:
• Young leaves turn lime green to yellowish
• Leaves yellow
• It resembles a nitrogen deficiency
• Can cause elongated stems which become woody at the base
• It occurs indoors if PH is too high and/or there is excessive calcium in the medium
• Overall smaller plant
• Dark green foliage
• Discoloured/burnt leaf tips and margins
How to treat a sulfur deficiency:
• Synthetic (salt) growers use a hydroponic fertilizer containing sulfur, or add an organic sulfur to a fertilizer that contains Epson salts
• Organic growers use a mushroom compost or most animal manures. (Keep in mind when using manures use only properly cured manures)
• Excess of sulfur in the soil causes no problems if the EC is relatively low. If the EC is high the plants will take up more sulfur blocking the uptake of other nutrients
How to treat sulfur toxicity:
• PH your water to 6 and flush with a min of three times the volume of water for the volume of growing medium
Synthetic nutrients, or salts are broken down and available for the plant to absorb immediately. Where organic nutrients require a complex process to break down the organic matter turning it into available forms of NPK. This is a biological process which requires micro-organisms of all kinds that perform a chemical and physical change to the organic matter. Different organisms are involved in different stages of this process.
Breakdown starts right after the organism or part of the organism dies. This organic material is colonized by micro-organisms using enzymes to oxidise the organic matter for the purpose of obtaining energy. When growing organically, incorporating earth worms (or red wigglers) into your soil will assist this process exponentially. During decomposition, the organic matter is broken down into simpler organic molecules which are required to decompose into mineralized nutrients. What does this mean?
Mineralization is a biological process where organic compounds are chemically converted by micro-organisms in the soil. These micro-organisms are comprised of bacteria and fungi which release enzymes causing oxidation. This releases energy and carbon feeding the micro-organisms. At the end of this process, you are left with nutrients in the mineral form. Plants require these nutrients to be in mineral form to up take them from the soil.
Micronutrients, also know as trace elements/trace nutrients main function is chlorophyll formation and as catalysts for the plant to process other elements. It is a clever idea to use cheat lave trace elements which are available in powder and liquid form. These should be added to the growing medium prior to planting. Trace elements are essential in very small amounts, so be sure to follow directions of the product exactly. It is also very easy for trace elements to reach toxic levels.
A chelate is an organic compound which contains ligand which bonds to electrically charged metal particles. This bond keeps metal ions such as zinc, iron, manganese soluble in water, which minimizes the reactions these metals would have with other materials in the growing media. Chelate metals are immediately absorbed by your roots because of there stability and solubility.
Humic acid is the most common natural chelate which can be added into the soil in a liquid or powder form. However, UV light causes chelates to rapidly decompose meaning you can apply it a few tines a week.
Magnesium, manganese and zinc all work to promote the same enzyme functions. Zinc also reacts with other elements to help form chlorophyll. Zinc is essential for stem growth and protein production as well as being a catalyst for most enzymes and auxins.
How to identify a deficiency:
• It is the most common found micronutrient deficiency
• Younger leaves show interveinal chlorosis
• New leaves and growing tips come in small
• Thin blades which contort and wrinkle
• Leaf tips and margins discolor and burn
• Burn spots grow progressively larger
• Often confused with manganese or iron deficiency
• Buds will contort into odd shapes, turn crispy, dry, and hard
• Stunted new growth including buds
How to treat a Zinc deficiency:
• Flush growing medium with a diluted mix of a complete fertilizer containing chelated trace elements( zinc, iron, and manganese)
• Add a quality brand hydroponic micronutrient mix containing chelated trace elements
Excess zinc prevents iron from functioning properly causing an iron deficiency and severely toxic plants can die very quickly.
Manganese (immobile nutrient)
Manganese is associated with lots of complicated functions which are fundamental in your plants chloroplast membrane system. Manganese helps utilize nitrogen and iron in the production of chlorophyll.
How to identify a Manganese deficiency:
• Young leaves show signs of interveinal chlorosis however the veins remain green
• Symptoms spread from younger to older leaves
• Necrotic spots develop
• Leaves turn pale and fall off
• Overall plant growth is stunted
• Maturation is prolonged
• Severe deficiency looks like a magnesium deficiency
How to treat a Manganese deficiency:
• Flush with a low PH water (5.5) then add a complete chelated micronutrient formula
• Growth slows down and overall vigor is lost
• Dark orange rusty brown spots on leaves causing tissue damage
Iron (immobile nutrients)
Iron is essential to the enzyme systems and to transport electrons during photosynthesis, respiration, and chlorophyll production. Iron allows plants to use the energy provided by sugars. Iron is important for the reduction of nitrates and sulphates as well as their assimilation.
How to identify an Iron deficiency:
• More common when the PH is above 6.5 and very uncommon when PH is below 6.5
• First signs are interveinal chlorosis on the smaller leaves. This starts at the opposite end of the leaf tip
• Leaf edges turn upwards
• Severe cases can cause the leaves to fall off
• Excess of copper can lead to an iron deficiency
• Leaves develop necrosis and fall off
How to treat a deficiency:
• Lower the soil PH below 6.5
• Avoid using fertilizers with substantial amounts of manganese, zinc, and copper. These prevent the uptake of iron
• Phosphorus and iron compete against each other for uptake
• Improve drainage
• Increase root zone temperature
• Apply chelated iron in liquid form
• Keep your nutrient solution out of the light, as UV rays can cause iron to precipitate
• Cow, horse, and chicken manure are good organic sources of iron and chelates
• Very rare
• High levels do not damage cannabis, but it can interfere with uptake of phosphorus
• Over application of iron chelate can kill the plant in a few days
How to treat toxicity:
• Flush with a minimum of 3x the volume of water to the volume of growing medium
Boron (immobile nutrient)
Boron isn’t the cause of many problems; however, it needs to be available for the entire life cycle of your plants. Boron’s behaviour is not fully understood yet, however, we do know boron assists with calcium uptake, as well as a number of other plant functions. There is convincing evidence supporting its role in cell division, differentiation, maturation, respiration, and pollen germination.
How to identify a Boron deficiency:
• The tips of stems and roots show abnormal growth
• Root tips are swollen, discoloured and stop stretching
• Growing shoots appear to have light burn from HID lighting
• First leaves thicken and become brittle
• Top shoots contort and turn dark
• Necrotic spots develop between leaf veins
• Roots become mushy, which is perfect for root rot and other diseases
• Leaves become thick, distorted, and wilt with chlorotic and necrotic spotting
How to treat a boron deficiency:
• Mix 1 tsp of boric acid per one gallon of water. Apply it as a soil drench
• Supplementation of hydroponic micronutrients containing boron
• Keep in mind boron is toxic if the solution is too concentrated
• Leaf tips turn yellow causing them to fall off
• Leaf necrosis
• Avoid using boric acid-based insecticides
Copper (immobile nutrient)
Copper is often found in the root system and can also be used as a fungicide. Copper is only required in small amounts and helps with carbohydrate metabolism, nitrogen fixation, the process of oxygen reduction, and also assists with the creation of proteins and sugars.
How to identify a copper deficiency:
• Copper deficiencies are common
• Young leaves and growing shoots wilt
• Leaves develop necrosis and turn a dark copper gray color
• Drooping can occur even when sufficiently watered
• Growth is slowed, yield is decreased
• A small deficiency can cause new shoots to die back
How to treat a copper deficiency:
• Cannabis rarely develops a copper deficiency
• Use a copper-based fungi (copper sulphate) (Do not apply if temperature is above 75 degrees to prevent burning of foliage)
• Apply a complete nutrient that contains copper
• Copper is extremely toxic even in a minor excess
• Overall plant growth is slowed
• Interveinal iron chlorosis
• Fewer branches grow
• Roots become dark, thick, and slow growing
How to treat a toxicity:
• Flush with a minimum of 3x the volume of water to the volume of growing medium
Its main function is converting nitrate to ammonium. It is used by cannabis in very small amounts and mostly active in roots and seeds.
How to identify a molybdenum:
• This micronutrient is rarely deficient
• Deficiency causes nitrogen shortage
• Older and middle age leaves yellow and may develop interveinal chlorosis
• Leaves will continue to yellow and roll up
• Growth is stunted
• Leaves may become severely twisted, die, and drop
• If using acidic soils, you may experience more deficiencies
• Too much Molybdenum can cause deficiency in copper and iron, however excess is uncommon in cannabis gardens.
Silicic acid is the form of silicon that the plants absorb. This helps keep iron and manganese levels consistent. Silicon accumulates in the epidermal cell walls where it forms hydrated amorphous silica. It also builds up in the walls of other cells. Having an abundant amount of soluble silicon is a great IPM tool because stronger cell walls resist pests and diseases more thoroughly as well as heat and drought tolerance.
How to identify a silicon deficiency:
• Decrease in yield
• New leaves grow deformed
How to treat a silicon deficiency:
• Water with PH adjusted potassium silicate solution
• There are no known symptoms of toxicity