Marijuana Grower's Handbook

by Ed Rosenthal

  Tea production is a brewing process. This process must stay aerobic. Non-beneficial organisms can grow more rapidly in reduced oxygen conditions. Anaerobic teas can result in the growth of some harmful bacteria and might be toxic to your plants. The brewing process is performed at a constant temperature. As the organisms grow and reproduce, it may elevate temperature. Using only high quality compost that contains bacteria and fungi, protozoa, and possibly nematodes will be the best to make Actively Aerated Compost Tea.

  BENEFITS OF USING COMPOST TEA

  •Improve plant growth as a result of protecting plant surfaces with beneficial organisms which occupy infection sites and prevent disease-causing organisms.

  •Improve plant growth as a result of improving nutrient retention in the soil, and therefore reduce fertilizer use, and loss of nutrients into ground and surface waters.

  •Improve plant nutrition by increasing nutrient availability root system.

  •Improve uptake of nutrients by increasing foliar uptake as beneficial microorganisms increase the times stomas stay open, while at the same time reducing evaporative loss from leaf surface.

  •Reduce water loss, improve water-holding in the soil, and thus reduce water use in your system.

  •Improves soil structure. Only the biology builds soil structure, and ALL the groups in the food web are required to be successful.

  AEROBIC COMPOST TEA SHELF LIFE

  Because this tea is a concentrated solution teeming with life, it is very perishable and should be used within 6-8 hours of brewing, although in the soil these organisms can keep on working for months. There will be microorganisms alive for 12 to 48 hours, but in reduced quantities.

  Compost tea is fast becoming a popular way to provide organic nutrients to plants growing in a soil medium. Organic Bountea comes enriched with the macronutrients N, P and K as well as providing beneficial microorganisms and natural stimulants to enhance plant growth and quality.

  There are three common indications of over-fertilization; wilting, a darker than normal shade of green in the leaves, and “crepeing,” or thickening of the leaf tissue (like crepe paper). This does not necessarily harm the plant nor cause death. It is a yellow light of caution: the plant is in a very rich environment and needs no additional nutrient supplementation. The soil or planting medium should be flushed with water and be given much lower doses of fertilizer. Be very wary of nutrient solutions stronger than 1200 ppm (EC 2.4 mS).

  FERTILIZER OVERDOSES

  Plants use a phenomenon described in the second law of thermodynamics that states that in a solution the concentration of salts becomes equal throughout. Liquid flows from the weaker to the more concentrated solution to achieve equilibrium. By maintaining a more concentrated solution in the tissue, the plant easily draws water and nutrients in.

  MANURE NOTICE

  It is critical to dry out animal manure and then compost it for at least six months before usage. Dry to prevent bacterial activity that may attack beneficial microorganisms, while also allowing free air passage. If your compost reaches high enough temperatures, it should kill most pathogenic organisms, as well as weed out seeds passed on by grazing animals. Cat and dog manure should never be used on edible plants because they carry many of the same pathogens as humans. Poorly composted manure can be a source of disease including salmonella.

  Normally, plants maintain a higher salt concentration than the surrounding environment so they easily absorb water. When the solution outside the plant becomes more concentrated than the solution inside, the plant cannot draw water and wilts.

  Fertilizer overdoses happen quickly (within hours or less) resulting in wilting followed by tissue damage. The symptoms of fertilizer overdose are sudden wilting with drying out and crinkling. It occurs when the nutrient content of the rooting medium develops such a high concentration of salts that the liquid is sucked from the plants, which have a lower concentration of dissolved solids. This back and forth flow is also called “osmotic pressure”. The plant maintains osmotic pressure according to the salt content of the water in the root zone.

  To save plants suffering from toxic overdoses of nutrients, run plain water through the system to flush out the medium so the nutrient concentration becomes diluted. When this happens, the process reverses and the plant is able to pull water inside, once again becoming turgid.

  Products that flush or clean the rooting medium can strip away accumulated salts. It is a good idea to use one of these products monthly to drench the roots, or run overnight in a hydroponic reservoir. For hydroponics, drain the reservoir of the old tired nutrient solution, refill with fresh water, add the cleaning product as recommended, run overnight, drain, and refill with fresh water and fertilizer. This method prevents nutrient imbalances that cause plant stress.

  Many nutrient deficiencies are the result of minerals being locked up (precipitated) because of a pH or nutrient imbalance. Rather than just adding more nutrients, check the pH first. If the pH needs to be adjusted, it can be changed by irrigating with pH-adjusted water.

  To get nutrients to the plant parts immediately, spray the leaves with nutrients. If plants do not respond to the foliar spray by producing normal new growth, they are being treated with the wrong nutrient. Calcium deficiency is not easily corrected with a foliar spray. For foliar application it is essential to use a very mild strength nutrient, 250-500 ppm is typical (EC 0.5-1.0 mS), pH should be 6.0-6.2. Purified water enters foliage much more effectively than hard water. Do not foliar feed during the flowering phase. It results in bad flavor and can provide mold and mildew an advantage. Do not foliar feed during darkness or within three hours of the night cycle, morning is best.

  Good mineral nutrients have a high pH buffering ability that allow the plants access to the nutrients. They also prevent mineral build-up in hydroponic systems. Green Dream from Flairform provides nutrients to the plant and has little effect on the pH of the water.

  MEASURING NUTRIENT SOLUTIONS

  To find out how much fertilizer to provide the plants you need to know how much is already present in the water or planting medium. The concentration of nutrients in the reservoir and growing medium changes over time as the plants absorb nutrients and water evaporates. An accurate measurement is the only way to be sure your plants are getting the optimal ingredients for maximal growth. Fortunately, chemical test kits and meters are readily available and inexpensive. Some meters combine several measurements, such as temperature, pH, and total nutrient level.

  www.amalgoldnutrients.com

  Bigger, sustainable yields are achieved when plants spend their time absorbing their nutrition more efficiently. Amino acids, which are organic compounds, increase growth rate and yields by providing bigger building blocks for tissue building. These are used by both the mychorrhizae and the roots. Amal Gold Organic Plant Superfood uses fresh fish proteins to provide a source of amino acids that promote rapid growth and development.

  Most chemical molecules are charged either positively or negatively. However, some are neutral. EC meters test the charge in the water so they only have the ability to read the charged molecules, not necessarily the amount of molecules of a particular chemical. To more accurately obtain a reading of the amount of a particular nutrient, use a soil test kit that breaks down the individual reading of each nutrient and measures it.

  Chemical test kits are actually more accurate because they can provide a measurement of each nutrient. Meters measure nutrient levels indirectly, based on the amount of electricity the nutrient solution conducts. The meters measure how efficiently electrons travel across probes through the solution. Pure, distilled water conducts virtually no electricity. The more nutrients and minerals in the solution, the more electricity is conducted.

  Electrical conductivity (EC) is the opposite of electrical resistance (measured in ohms), so the unit is the mho or, in metric units, the siemen. Since the current in even highly concentrated solutions is tiny, meters typically read in either 1/1,000th of an mho (
a milli-mho or mMho), or 1/1,000th of a siemen (a milli-siemen or mS).

  Some meters provide readout in EC and others read out as Total Dissolved Solids (TDS) or Parts Per Million (ppm) of nutrients. Even those that read directly in TDS or ppm are measuring electrical conductivity (EC) and then estimating the concentration of solids. A measurement of 1,000 ppm means that 1,000 units of nutrients are present for every million units of water. It’s important to realize that TDS or ppm readings only tell you the total nutrients in a solution—not how much of each nutrient is in the mix.

  Likewise, ppm and TDS vary depending on the type of nutrients present and the conversion factor being used. The conversion calculation is based on what manufacturers consider a typical hydroponic solution. The most common are based on measurements of two types of solutions—either 4-4-2 (40% sodium sulfate, 40% sodium bicarbonate, 20% sodium chloride) or sodium chloride (NaCl)—but they produce different results. The conversion factor for a 4-4-2 solution is approximately 700 x EC in mili-siemens (mS). The NaCl conversion is roughly 500 x EC. This means that the same solution, producing the same EC, converts to either 2100 ppm or 1500 ppm, depending on the scale the manufacturer has chosen. These conversion differences reflect the disparity in conductivity between different nutrients.

  When managing a hydroponic system, it is important to balance the correct amount of nutrients in clean, pH adjusted water. The Dosa Easy-Feed System allows the grower to arrange water and nutrient components to meet their individual needs. It allows up to eight different nutrients, additives, and pH adjusters in series at 60 psi.

  The unique inline mixer (top) oxygenates the water as it mixes nutrients. Controls (below) allow the grower to read and manage the system.

  Proper maintenance of your meter includes periodic recalibration as well as careful cleaning and storage. If the probe is contaminated or dirty, it affects the accuracy of the meter’s reading. Similarly, many meters need to have their probes kept moist to protect the electrodes. Check the manufacturer’s instructions for how to properly store your probe (most recommend an acidic solution).

  SOME COMMON ORGANIC FERTILIZERS

  These are average percentages; the amount of nutrients in a particular sample may vary. The percentage of nutrients in manures depends on water content. Commercial manures are usually rated higher.

  Nutrient types and calibration are not the only things that can affect an EC or TDS meter’s readings. The EC of your solution also varies based on its temperature since the speed of electron travel is measured, and that increases as the solution gets warmer. Make sure you are measuring the solution at close to the same temperature each time. This won’t be an issue if you are using a system with an aquarium heater or other method of maintaining consistent solution temperature. But if the gardening space (and nutrient solution) gets warmer after the lights have been running, take nutrient readings at the same time of day or point in the light cycle.

  Soil test kits provide individual readings of nutrients. Meters provide only an overall reading.

  It’s important to realize that even a properly calibrated and maintained meter used under perfect conditions will not give you a precise reading of your nutrient concentration. Even quality meters are only accurate in the range of approximately +/-5%.

  What meters are exceptionally useful for is detecting change in your nutrient solution over time and potentially damaging concentrations of nutrient salts in your solution or growing medium.

  If the plants transpire 50% of the water out of the reservoir, the solution’s concentration can become dangerously high. Similarly, because your plants take the nutrients they need from the solution and leave the rest, unused salts can build up in the solution. If you just add make-up nutrients without knowing which have been left behind, toxic concentrations can result. If the medium is allowed to dry out, it can accumulate up to 2 or 3 times the nutrient concentration as the starting solution.

  As with pH, when the concentration gets too high, your plants effectively lock out water/nutrient uptake. At a ppm of 2000, the osmotic pressure is strong, and plants’ roots use more energy to extract water from the salty solution. As the level of nutrient salts increases, the chemicals start to fight each other for water, causing the roots to work harder. The more energy the plants use to extract water, the less they have for growth.

  Keeping the solution in the root zone at a moderate concentration of roughly 800-1200 ppm will produce reliable results. Use your nutrient meter to compare the concentration in both the growing medium and the reservoir. When readings in the medium substantially exceed those in the reservoir, it’s time to flush the system with pure water.

  NUTRIENT DEFICIENCIES

  BORON (B)

  Boron (B) deficiency is not common. It occurs very occasionally in some western soils. Boron is not mobile.

  Symptoms

  The first sign of a boron deficiency is the browning or graying of the growing tips followed by their death. Soon after, the lateral shoots start to grow, but then die. Shoots appear sunburned, twisted and a bright green color. The leaves develop small brown necrotic dead spots that look like strawberry seeds, and are surrounded by an area of dying tissue between leaf veins. Boron deficiency resembles a calcium deficiency, but can be differentiated by the small size of the necrotic areas.

  Stems and petioles (leaf stems) are brittle and show signs of hollowness. Boron deficiency only affects newer growth.

  Roots become stunted and the smaller secondary roots become short and swollen as the root tips die. The roots are vulnerable to fungal and bacterial attacks that rot the root hairs and cause discoloration.

  Excess boron, which is rare and is caused primarily by over-fertilization, causes the yellowing of the leaf tips which progresses inward. The leaves drop and the plant dies.

  Role in plant nutrition

  Boron is important in the processes of maturation, pollen germination, and seed production. It also aids in cell division, protein formation, healthy leaf color, and plant structure formation. Proper amounts keep stems, stalks, and branches strong and help plant cells maintain rigidity. It helps calcium maintain solubility.

  Boron deficiency. Photo: Turkish

  Problem Solving

  Treat a Boron deficiency foliarly or through the irrigation water, using one teaspoon (4.9cc) of boric acid (available in drug stores) per gallon of water (1.3cc per liter). Fast-acting solutions also include borax, compost and compost teas.

  CALCIUM (CA)

  Calcium (Ca) deficiency is rare outdoors except in very acidic soils. The deficiency is occasionally found in planting mixes and is more common in hydroponics. Ca deficiency sometimes occurs in soilless growing mediums that have not been supplemented with lime, which is composed mostly of Ca.

  Distilled and reverse osmosis water, as well as some tap water, lack significant amounts of dissolved Ca. This can lead to Ca deficiency unless the water is supplemented with Ca.

  Symptoms

  Ca deficiency stunts plant growth and makes the leaves turn dark green. Large necrotic (dead) blotches of tan, dried tissue appear mostly on new growth but also on other plant parts along leaf edges. Young shoots crinkle and get a yellow or purple color. In severe cases they twist before they die. Necrosis appears along the lateral leaf margins. Problems migrate to the older growth, which browns and dies. Stems and branches are weak, lack flexibility and crack easily.

  The root system does not develop properly, leading to bacterial problems that cause root disease and die-off. The roots discolor to a sickly brown. Ca is semi-mobile.

  Role in plant nutrition

  Ca strengthens plant cell walls and therefore stems, stalks, and branches, and it aids in root growth—mostly the newer root hairs. It travels slowly and tends to concentrate in roots and older growth. Ca also enhances the uptake of K.

  Problem Solving

  Outdoors, add Ca to acidic soils to bring them into the pH range of 5.9-6.5. Use dolomitic lime, or garden lime.

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p; Early-stage calcium deficiency. Photo: Senseless

  Calcium deficiency. Photo: Senseless

  Dolomitic lime, or garden lime, can be added to planting mixes before potting. It provides Ca and also helps stabilize pH over a period of time.

  Both planting mediums and hydro systems can be fertilized as directed using a commercial Calcium-Mg (Ca-Mg) formula; this provides instant availability to the plant. It can also be used in planting mixes. Growers often use Ca acetate or Ca-Mg acetate.

  Ca nitrate Ca(NO3)2 is a water-soluble fertilizer that supplies both Ca and nitrogen. It provides a very soluble form of Ca to the roots and can also be used as a foliar spray. This formula gets Ca to the plant very quickly. Be careful not to add Ca nitrate during the flowering stage because it provides unwanted excess nitrogen.

  There are a number of brands of liquid Ca or liquid lime that are absorbed by the roots.

  One teaspoon of hydrated lime per gallon of water provides relatively fast absorption. Dolomitic limestone, which contains Mg and Ca, takes longer to absorb. It is a good ingredient to place in planting mixes to prevent deficiency.

  Ground eggshells, fish bones and seashells also break down over the season and add Ca to the soil. You can soften them by soaking them in vinegar or lemon juice.

  Gypsum, Ca sulfate (CaSO4), can be added to outdoor soils to increase Ca content without affecting the pH too much. It should not be added to soils with a pH below 5.5 because it interacts with aluminum (Al), making it soluble and poisonous to the plants.