Choosing the Right Strain - Indica or Sativa?

The Sativa High

The sativa high is often characterized as uplifting, energetic and known for arousing brain activity. The effects of sativa marijuana are mostly cerebral. They give a uplifting high that is great for work, as well as providing a good measure of pain relief for certain symptoms. Some pure sativas are also very high in THC content. They are known to have a quite spacey, or hallucinogenic, effect. Sativas are a good choice for daytime smoking.

The Indica High

The indica highs are most often described as a pleasant calming body buzz. Indicas are great for relaxation, stress relief, and for an overall sense of calm and serenity. Marijuana indicas are also very effective for overall body pain relief, and often used in the treatment of insomnia and anxiety. They are the late evening choice of many smokers as an all night sleep aid. A few pure indica strains are very potent in THC, and will cause the "couchlock" effect, enabling the smoker to simply sit still and enjoy the experience of the smoke. Indica also has higher levels of CBD canabidiol.

Cannabidiol (CBD) is a psychoactive cannabinoid found in Cannabis. It is a major constituent of the plant, representing up to 40% in its extracts.

CBD alone is not intoxicating, but displayed sedative effects in animal tests. Some research, however, indicates that CBD can increase alertness. It may decrease the rate of THC clearance from the body, perhaps by interfering with the metabolism of THC in the liver. CBD appears to affect both the CB1 and CB2 receptors- with higher affinity for the CB2 receptors. Cannabis indica dominant strains of the plant are known to be higher in CBD than Cannabis sativa strains.

Medically, it appears to relieve convulsion, inflammation, anxiety, and nausea, and to inhibit cancer cell growth. Recent studies have shown cannabidiol to be as effective as atypical antipsychotics in treating schizophrenia.

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Diagnosing & Treating Nutrient Toxicity & Deficiencies

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Nitrogen (N) - Mobile

Deficiency

Nitrogen deficiency is the most common nutrient deficiency. Growth slows, lower leaves cannot produce chlorophyll and yellow between veins while veins remain green. Yellowing progresses through entire leaf, eventually causing ti to die and drop off. Stems and leaf undersides may turn reddish-purple, but could be a sign of P deficiency. N is very mobile, dissipates quickly, and must be added regularly to sustain fast growth.

• Older leaves will yellow between veins then entirely.
• More and more leaves will yellow. Severly affected leaves drop.
• Stems and leaf vein undersides might turn reddish-purple.
• Younger leaves develop interveinal chlorosis.
• Foliage yellows and leaf drop is severe.

Treating Deficiency

Fertilize with N or complete N-P-K fertilizer for results in 4 to 5 days. Fast acting organic sources of (N)itrogen are: seabird guano, fish emulsion and blood meal. Bio-fertilizers will also stimulate (N) uptake.

Toxicity

Toxic levels of Nitrogen causes excessively lush soft foliage susceptible to stress, insect and fungal attacks. Stems weaken and may fold over easily. Water uptake is restricted. If severe, leaves turn a brownish-copper, dry and eventually fall off. Roots develop slowly and tend to rot. Flowers are smaller. Ammonium toxicity is common in acidic soils. Nitrate toxicity is more prevalent in alkaline rich soil.

• Exccessively lush green foliage.
• Weak stems and slow root growth.
• Flowers become whispy.
• Leaves brown, dry and fall off.

Treating Toxicity

Flush the growing medium with mild complete fertizlier. Flush a minimum of three times the volume of water for the volume of growing medium. Monitor (N)itrate closely.

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Phosphorus (P) - Mobile

Spotting Phosphorus Deficiency

Phosphorus deficiency causes stunted growth. Leaves are smaller bluish-green and often covered with "blotches". Stems, leaf stems and main veins turn reddish purple, starting with the undersides. Reddening may not be well pronounced. Older leaf tips darken and curl downward. If severe, leaves develop large, dark purplish dead blotches that turn bronzish-purple, dry, shrivel, contort and finally drop off. Plants vulnerable to stress produce small, measly buds. Deficiency aggravated by clayey, acidic and soggy soil. Deficiencies most common when: growing medium pH is about 7, pH is below 5.8 with excess of Fe and Zn, and or soil is chemically bound with phosphates.

• Stunted and slow growth.
• Dark bluish-green leaves often with dark blotches.
• Plants are smaller overall.
• Leaves turn bronzish-purple, contort and drop off.

Treating Deficiency

By lowering pH to 5.5 - 6.2 (in hydroponic applications), 6 - 7 pH in clay soils, 5.5 - 6.5 pH for potting soils. An excess of Fe and Zn in acidic soil makes phosphorous unavailable. Add complete hydroponic fertilizer with phosphorous. Organic solutions include fine grade bat guano, steamed bone meal, natural phosphates or barnyard manure.

Signs of Phosphorus Toxicity

Signs of phosphorus toxicity take several weeks to appear, especially if excesses are buffered by a stable pH. Cannabis loves (P)hosphorus and many varieties tolerate high levels. In excess, P interferes with calcium, copper, Fe, Mg and Zn stability and uptake. P deficiencies manifest as a lack of Zn (most commonly found), Fe, Mg, calcium and copper.

Treating Toxicity

Flush growing medium with mild complete fertilizer. Flush a minimum of three times the volume of water for the volume of growing medium.

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Potassium (K) - Mobile

Spotting Potassium Deficiency

Older leaves, first tips and margins, then whole leaves turn dark yellow and die. Stems become weak and often brittle. Plants become susceptible to disease. K is usually present in soil, but locked in by high salinity. Internal temperature of foliage climbs, causing protein cells to burn and degrade. Excessive evaporation from leaf edges causes burning.

• Healthy dark green foliage.
• Leaves loose luster, weak scrawny branches.
• Leaf margins turn rusty brown, curl up and dry.
• Older leaves yellow and develop rust colored blotches.
• Leaves curl up, rotting develops and old leaves drop.
• Flowering retarded and greatly diminished.

Treating Deficiency

Fertilize with comple N-P-K fertilizer. Use organic soluble potash mixed with water, however adjust the pH to 6.5 before application. Foliar feeding is not recommended.

Signs of Potassium Toxicity

It is difficult to diagnose. The absortion of Mg, Mn and sometimes Zn and Fe are slowed. When these nutrients are deficient P is often toxic!

Treating Toxicity

Flush growing medium with mild complete fertilizer.

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Magnesium (Mg) - Mobile

Deficiency

Magnesium deficiency is common indoors. Lower and later middle leaves develop yellow patches between darker green veins and rusty brown spots on leaf margins, tips and between veins. Leaf tips usually curl upward before dying. The entire plant could discolor in a few weeks and if severe, turn a yellow / whitish tinge before browning and dying. Minor deficiencies can escalate and cause a diminished harvest.

It is often in soil but unavailable because soil is too wet / cold or acidic / cold. And excess of K, ammonia (nitrogen) and calcium (carbonate) bind Mg in soil. Small root systems are unable to take in enough Mg to supply heavy demand. A high EC slows water evaporation and diminishes Mg availability.

• Inter-veinal yellowing, irregular rust-brown spots on older leaves
• Leaf tips turn brown and curl upwards
• Rust-brown spots multiply and inter-veinal yellowing increases
• Spots and yellowing envelop entire plant
• Leaves dry and die in extreme cases

Treating Deficiency

Water with two teaspoons of Epson salts (magnesium sulfate) per gallon of water. For fast results, spray foliage with 2 percent solution of Epsom salts. Greening starts at top of plant and moves downward. Add same dose until symptoms disappear. Or apply magnesium sulfate monohydrate. Add fine dolomite lime when planting to ensure a supply of calcium and Mg.

Keep root zone and nutrient solution 70 - 75 degrees F. Keep ambient air temperature at 75 degrees day and 65 degrees at night. Use a complete fertilizer with Mg. Keep soil pH above 6.5, keep hydroponic pH above 5.5, and lower high EC for a week.

Toxicity is rare and difficult to discern with the naked eye. If extremely toxic, Mg conflicts most often with calcium, especially in hydroponics. Toxic buildup in soils is uncommon.



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Zinc (Zn) - mobile

Zinc Deficiency

Most common micronutrient found deficient. First, younger leaves will exhibit inter-veinal chlorosis. New leaves and growing tips develop small thin blades, contort and wrinkle. Leaf tips and later margins discolor and burn. Often confused with a lack of manganese or Fe, but when deficiency is severe, new leaf blades contort and dry out. New growth is stunted, blower buds contort, turn crispy dry and are often hard.

• Inter-veinal chlorosis of young leaves
• New leaves develop thin, whispy leaves
• Leaf tips discolor, turn dark and die back
• New growth contorts horizontally
• New bud and leaf growth stops

Treating Zinc Deficiency

Flush growing medium with a diluted complete fertilizer containing chelated trace elements including Zn, Fe and Mn. Or add a quality brand of hydroponic micronutrient mix containing chelated trace elements.

Zinc Toxicity

Zn is extremely toxic in excess. Severely toxic plants die quickly. Excess Zn interferes with Fe's ability to function properly and causes a Fe deficiency.



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Manganese (Mn) - immobile

Manganese Deficiency

Young leaves yellow between veins and veins remain green. Symptoms spread to older leaves. Dead spots develop on severely affected leaves before they fall off. Plant is stunted and maturation prolonged. Severe deficiency looks like a sever lake of Mg.

• Inter-veinal chlorosis of young leaves
• Inter-veinal chlorosis of progressively older leaves
• Dead spots develop on acutely affected leaves
• Overall growth is stunted

Manganese Toxicity

Young and newer growth develop chlorotic dark orange to dark rusty brown mottling, first on young leaves before progressing to older leaves. Slow growth loss of vigor. Toxicity is compounded by low humidity. The additional transpiration causes more manganese to be drawn into foliage. Excess manganese causes a deficiency of Fe and Zn.



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Iron (Fe) - immobile

Iron Deficiency

Common when the pH is above 6.5 and uncommon when the pH is below 6.5. Symptoms may appear during rapid growth or stressful times and disappear by themselves. First symptoms appear on smaller leaves as interveinal chlorosis where veins remain green and areas between veins turn yellow. Interveinal chlorosis starts at the opposite end of the leaf tip, the apex of the leaves attach by the petiole. Chlorosis becomes progressively acute. Leaves fall off in severe caes. Fe deficiency is somestimes traced to an excess of copper.

• New growth turns pale green, young leaves yellow in between veins starting at the petiole.
• More leaves yellow and develop interveinal chlorosis.
• Larger leaves yellow and develop interveinal chlorosis.
• In acute cases, leaves develop necrosis and drop

Treating Iron Deficiencies

Lower soil pH to 6.5 or less. Avoid fertilizers that contain excessive manganese and Zn. Improve drainage and increase root zone temperature. Apply liquid chelated. Apply a complete balanced hydroponic formula. Organic sources include well-rotted cow, horse or chicken manure.

Iron Toxicity

Excess Iron (Fe) is rare. High levels of Fe do not damage cannabis, but can interfere with P uptake. An overdose causes leaves to turn bronze accompanied by small dark brown leaf spots. If Fe chelate is over-applied, it will kill the plant in a few days.

Treating Excess Iron

Leach plants heavily.



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Sulfur (S) - immobile

Sulfur Deficiency

Sulfur deficiency will cause young leaves to turn lime green to yellowish. As short-age progresses leaves yellow interveinally and lack succulence. Veins remain green. Leaf stems, petioles, turn purple. Leaf tips can burn, dark and hook downard. S deficiency resembles nitrogen deficiency. Acute deficiency causes elongated stems that become woody at the base. Most common when pH is too high or when excessive calcium is present and available.

• Similar to nitrogen deficiency; older leaves turn pale green.
• Leaf stems turn purple. More leaves turn pale green.
• Interveinal yellowing
• Acute cases include purple leaf stems and yellow leaves.

Treating Sulfur Deficiencies

Fertilize with hydroponic formula that contains sulfer (S). Lower pH to 5.5 - 6. Add inorganic S that contains magnesium sulfate (Epsom salts). Organic sources include well-rotted mushroom composts and most animal manures.

Sulfur Toxicity

Causes no problems if the EC is relatively low. At high EC plants take up more "available" S, which blocks uptake of other nutrients. Excess symptoms include overall smaller plants and uniformly smaller dark green foliage. Leaf tips and margins burn when severe.

Treating Sulfur Toxicity

Flush growing medium with mild complete fertilizer. Check pH of runoff solution. Correct input pH to 6.0. Flush a minimum of three times the volume of water for the volume of growing medium.

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Desired pH Ranges for Cannabis Growth

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