Première semaine de flo , je voulais remporter dans de plus grand pot mais quand j'ai vu la faible masse racinaire j'ai changé d'avis et je fais la Flor en pot de 3,5 litre , plante plutôt sensible a l'arrosage il faut lui donner très peu d'eau mais très souvent ! J'ai dej a des feuilles qui jaunisse et meurt sur 2 des 3 plantes, mais la 3 ème elle est très jolie et saine , curieux .pour l'instant le stretch est vraiment discret Defoliation et lollipop a venir

J'ai l'impression qu'il y a une carence en fer , je vais regarder pour arranger sa j'aimerais sauvegarder cette plante , les boutures malheureusement ne prennent pas où avec beaucoup de mal , j'en est seulement 3 sur 15 qui racines au bout de 15 jours ,qu'elle échec, je vais réessayer en changeant quelques paramètres ! Si quelqu'un a une idée je suis preneur

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This is my second growth in a suitcase, I got 30 grams of dry flowers from the first growth, but this growth together with FastBuds is obviously much better than the first one :) although the girl's leaves burn from the light, which is only 10-15 cm from the flowers, but the girl copes with it perfectly :) good luck to everyone.

Nicely budding along St the back into week 3 in the mildel row and freshly pooped new f1

Sie haben das Umtopfen ganz gut überstanden. Eine von den dreien macht ganz gut los. Die anderen beiden haben wohl noch etwas Stress durch das Umtopfen. Alle 3 sind Samen der selben Genetik aber selbstverständlich auch verschiedene Phenotypen, sie werden auf jeden Fall unterschiedlich wachsen und aussehen. Ich finde aber No-till besser als Stecklinge und je besser der Züchter um so weniger Phenos 😉 Wir werden sehen... 😎

Dienstag (26.11) beschnitten erholen sich sehr gut

Waiting on buds to start swelling. Have a few rust spots on a couple of leaves. Nothing too major, may need to recalibrate my PH pen before next feeding. Starting to get a little more pungent of a smell. Sweet and earthy in the whole tent so far.

Alles gut soweit, bin zufrieden mit meinen Fast Buds 💚😎 Dünger kommt später dazu, EC der Erde liegt bei 2,2 Sport frei...

They're getting fat! There are 3 skywalkerhaze completely full of hair and resin overflowing! I used atami's bloombooster! UV Light has been added for the last few weeks! Thanks

all nutrients are in ger section if not other mentioned all by maufactures instructions. no problemsso far she looks a liilt rough but she should do fine.

next week of the flowering stage in the life of this amazing beauty her big leafes still amazes me. all nutrients are in ger section if not other mentioned all by maufactures instructions.

next week of the flowering stage in the life of this amazing beauty her big leafes still amazes me. all nutrients are in ger section if not other mentioned all by maufactures instructions.

and another week growing big and strong. all nutrients are in ger section if not other mentioned all by manufactures instrucktions. maby more lst at end of the week.

and next week of this lady. nothing special i just let her grow. all nutrients are in ger section if not other mentioned all by maufactures instrucktions.

all nutrients are in ger section if not other mentioned all by maufactures instructions. no problemsso far she looks a liilt rough but she should do fine.

Day 50/51 form sprouting Bloom W4 D23/24 Defoliation on all girls. Removed all nodes and side branching. Leave only main branching from main stem. Depending on plant from 10-14 branches in total is left on girls. About 60-65cm off usable canopy left on plants. Total 1.78m3 off canopy density. Cut lots of buds with longer nodes, leaving only buds with short node from main branch (bottom) Lott's off leaves removed also, good light penetration now, on lowest bud we have around 250/350ppfd Installing another trellis net over girls More frequent watering from this week till end off week 7 More power to light also, from 900-1250ppfd at canopy levels. Food strength stay the same, lowering humidity a bit will trigger plants to consume more food. Lowering day and night temperature for 1c, max temp is 26.5c in day time, in dark period it drop to 19c. Start getting little humidity spike @ 65%RH right when lights go out. Light intensity @ 950-1250 ppfd , Light distance - 50-60cm, DLI - 50/55, Light Interval 12/12 Day RH - 55/63%, Night RH - 45/55%, Day Temperature - 24c/26c, Night Temperature - 19/21c, Leaf temperature 24/25c, CO2 1000/1350ppm, VPD 1.2 45s ON time, 20min OFF time @ Day misting 40s ON time, 20min OFF time @ Night misting NT-Nutrient Tank PH - 5.99/6.20, EC -2.0/1.93, Water Temperature - 19/21

The ideal PPFD level for seedlings is between 100-300 micromoles per square meter per second (μmol/m²/s). This softer lighting mimics the diffused sunlight of early spring, providing enough energy for seedling-stage plants to develop their initial leaves without overwhelming them. at 48 inches from light sources, the seedlings receive around 150-180μmol/m²/s, as they grow they grow towards the higher levels of ppfd naturally. Urine is a liquid waste product as a result of our kidneys cleaning and filtering our blood. Typically, urine contains around 95% water and the rest are a mix of salts including sodium, potassium and chloride, urea, and uric acid. Due to the high water content in pee, the more you drink, the more you have to go. For a healthy person, human urine typically has a pH of around 6.2 with a range of 5.5-7.0. A person’s diet and alcohol consumption can also affect the pH of their urine. The main organic component of urine is urea, a combination of ammonia and carbon dioxide, which is the byproduct of our bodies breaking down proteins into usable amino acids. Urea is very high in nitrogen, a key ingredient to healthy leafy growth in plants. In addition to being very nitrogen-rich, urine also contains dissolved phosphorus that’s immediately available to plants, making urine a quick-acting fertilizer. If you own a dog, you may be familiar with yellow patches on your lawn where your pet has peed. Dogs and cats excrete fresh urine with a higher quantity of urea than humans do and that can more easily burn a plant upon contact. Human urine contains less urea and thus less ammonia. Despite Bear Grylls drinking urine in his popular survival shows, urine is not sterile. It picks up trace amounts of bacteria as the sterile version passes through the bladder, the urinary tract and comes in contact with the skin. Still, the health risks of using urine are very low because urine does not typically contain pathogens found in feces. Infectious diseases like cholera are spread through water sources contaminated by poop. In areas with poor sanitation, there is no way to separate solid and liquid waste which is why all untreated mixed sewage can pose significant public health risks. Only 10-15% of all nutrition you ingest is absorbed, all the rest is disposed of in the urea of urine, 95% Water, 5% Urea. Human urine consists primarily of water (91% to 96%), with organic solutes including urea, creatinine, uric acid, and trace amounts of enzymes, carbohydrates, hormones, fatty acids, pigments, and mucins, and inorganic ions such as sodium (Na+), potassium (K+), chloride (Cl-), magnesium (Mg2+), calcium (Ca2+), ammonium (NH4+), sulfates (SO42-), and phosphates (e.g., PO43-).1 A Representative Chemical Composition of Urine Water (H2O): 95% Urea (H2NCONH2): 9.3 g/l to 23.3 g/l Chloride (Cl-): 1.87 g/l to 8.4 g/l Sodium (Na+): 1.17 g/l to 4.39 g/l Potassium (K+): 0.750 g/l to 2.61 g/l Creatinine (C4H7N3O): 0.670 g/l to 2.15 g/l Inorganic sulfur (S): 0.163 to 1.80 g/l The pH of human urine ranges from 5.5 to 7, averaging around 6.2. The specific gravity ranges from 1.003 to 1.035. Significant deviations in pH3 Chemical Concentration in g/100 ml urine Water 95 Urea 2 Sodium 0.6 Chloride 0.6 Sulfate 0.18 Potassium 0.15 Phosphate 0.12 Creatinine 0.1 Ammonia 0.05 Uric acid 0.03 Calcium 0.015 Magnesium 0.01 The element abundance depends on diet, health, and hydration level, but human urine consists of approximately: Oxygen (O): 8.25 g/l Nitrogen (N): 8/12 g/l Carbon (C): 6.87 g/l Hydrogen (H): 1.51 g/l Morning piss is best, diluted to 6-10 parts water. Breaking Down Nitrogen Forms & Their Impact: Forms of Nitrogen: Nitrogen, comes in three primary forms: ammonium, nitrate, and urea. Ammonium (NH4+) carries a positive charge, nitrate (NH3–)carries a negative charge, while urea ((NH2)2CO) carries no charge. Natural Processes in Media: Once these nitrogen forms are introduced into the growing media, natural processes kick in. Bacteria play a vital role, converting urea to ammonium or ammonium to nitrate. This latter conversion releases hydrogen ions, increasing media acidity. Urea Conversion: Urea undergoes rapid conversion to ammonium in the soil, usually within two days. Both urea and ammonium are often grouped together and referred to as ammoniacal nitrogen. When plants absorb nitrogen, they typically release a molecule with the same charge to maintain internal pH. This process can also alter the pH of the media surrounding the roots. pH Effects of Nitrogen Uptake: Ammonium (NO4) Uptake and pH: When plants absorb ammonium, they release hydrogen ions (H+) into the media. This increases the acidity of the media over time, decreasing the pH. Nitrate (NO3) Uptake and pH: Plants take up nitrate by releasing hydroxide ions (OH–). These ions combine with hydrogen ions to form water. The reduction in hydrogen ions eventually reduces the media acidity increasing the pH. Nitrate (NO3) Absorption Variations: Sometimes, plants absorb nitrate differently, either by taking in hydrogen ions or releasing bicarbonate. Like hydroxide ions, bicarbonate reacts with hydrogen ions and indirectly raises the media pH. Understanding these processes helps in choosing the appropriate fertilizer to manage media pH. Depending on the nutrients present, the media’s acidity or alkalinity can be adjusted to optimize plant growth. Risks of Ammoniacal Nitrogen: Plants can only absorb a certain amount of nitrogen at a time. However, they have the ability to store excess nitrogen for later use if needed. Nitrate (NO3) vs. Ammonium (NH4): Plants can safely store nitrate, but too much ammonium can harm cells. Thankfully, bacteria in the media convert urea and ammonium to nitrate, reducing the risk of ammonium buildup. Factors Affecting Ammonium (NH4) Levels: Certain conditions like low temperatures, waterlogged media, and low pH can prevent bacteria from converting ammonium. This can lead to toxic levels of ammonium in the media, causing damage to plant cells. Symptoms of Ammonium (NH4) Toxicity: Upward or downward curling of lower leaves depending on plant species; and yellowing between the veins of older leaves which can progress to cell death. Preventing Ammonium (NH4) Toxicity: When it comes to nitrogen breakdown of a nutrient solution, it’s crucial not to exceed 30% of the total nitrogen as ammoniacal nitrogen. Higher levels can lead to toxicity, severe damage, and even plant death. Ideal Nitrogen Ratio for Cannabis: Best Nitrogen (NO3) Ratio: Research shows that medical cannabis plants respond best to nitrogen supplied in the form of nitrate (NO3). This helps them produce more flowers and maintain healthy levels of secondary compounds. Safe Ammonium (NH4) Levels: While high levels of ammonium (NH4) can be harmful to cannabis plants, moderate levels (around 10-30% of the total nitrogen) are are considered most suitable. This level helps prevent leaf burn and pH changes in the media. Nitrogen: nitrate (NO3-) and ammonium (NH4+) Nitrogen is mobile in the plant. When it is in the soil it is mobile as Nitrate NO3– and is immobile as Ammonium NH4+ All those nutrients should be in ionic form, either in the soil or in a nutrient solution. Ions are simply the atomic or molecule form having +ve or –ve charge. As we know, the positive attracts the negative, and the same charge elements will repel each other; this power of charge represents the strength of the element. The positive ions are known as Cation, while negative ions are Anions. The anions want to disperse themselves to even concentrations, so they move from higher concentrations to lower concentrations. As we look at the soil structure, it’s a composition of particles; those particles attract the positive ions (+Ve), repel the Negative ions (-ve), and float freely in the water. This attraction of Cation by the soil particles is called Cation Exchange Capacity (CEC), which measures the number of cations that can be retained by the soil particles. The higher the CEC, the more Cation Nutrients can be stored in the soil. As a result, the higher CEC soils can become more nutrient-rich; also, keep in mind the soil composition is diverse and varies among different soil types.

Que pasa familia, vamos con la novena semana de floración de estas Gorilla Cookies Fast Flowering, de FastBuds. Agradezco a Agrobeta todos los kits obtenidos de ellos 🙏. Hasta aquí veis que llevan buen progreso y el color que se marcan es espectacular. Vamos al lío, el ph se controla en 6.2 , la temperatura la tenemos entre 22/24 grados y la humedad ronda el 50%. El fotoperiodo a 12-12. Estás próxima machete. Agrobeta: https://www.agrobeta.com/agrobetatiendaonline/36-abonos-canamo Hasta aquí todo, Buenos humos 💨💨💨

RELATIVE HUMIDITY The term ‘relative humidity’ (RH) refers to the amount of water vapor in the air and is usually expressed as a percentage (e.g. 50% RH). This can have a major impact on how cannabis plants grow. Low humidity means less water in the air and results in increased evaporation and water use. Excessive humidity comes with its own problems, including creating an ideal environment for pests, mildew, and mold to grow. One key factor related to humidity that is often left out of the conversation is vapor-pressure deficit (VPD) – the difference between the maximum water vapor the air can hold at a given temperature and RH. Although not all growers measure VPD, it significantly influences stomata activity and is directly related with transpiration rate and metabolism. A VPD that is too high means drier air and increased evaporation and transpiration. Too low a VPD can lead to slowed transpiration and reduced growth. Since slowed transpiration reduces nutrient uptake, both too high and too low of a VPD may appear as nutrient deficiencies. It is VPD that drives transpiration and nutrient uptake in plants; the uptake of water at the roots is determined by the loss of water through the shoots, and the loss of water through the shoots is determined by how much water is in the air. Humidity levels influence the rate of water evaporation from the leaves of cannabis plants, which directly affects the tension and suction created within the plant. Higher humidity levels can reduce the rate of evaporation, potentially impacting the negative pressure and water transport efficiency within the plant. CARBON-e DIOXIDE Carbon dioxide is essential for photosynthesis. Light energy is used to convert CO2 and H2O into sugar and oxygen. As the CO2 concentration increases, the rate of photosynthesis increases until a saturation point where no more CO2 can be absorbed. The guard cells (stomata) previously mentioned are specialized to regulate gas exchange, working to optimize the movement of oxygen, water, and CO2 in and out of the shoots. Plants cultivated outside typically don’t need supplemental CO2 (because nature knows what it’s doing). Indoor growers however, may find themselves needing additional carbon dioxide to maximize yields and improve plant growth and development. Without fresh air for plants to exchange oxygen for carbon dioxide, the CO2 concentrations can become low, hindering photosynthesis and dramatically reducing plant growth. Although CO2 is a naturally occurring gas that both humans and plants use, it is invisible and odorless and can be fatal at high-levels. If you’re supplementing carbon dioxide in your grow room, ensure there are no leaks in any CO2 devices and always use a CO2 monitor and alarm. 0.02% Life unsustainable 0.03% Life OK 0.04% Current ambient atmospheric co2 0.04%-0.1% =400-1000ppm standard indoor co2. 0.1%-0.2% =1000-2000ppm (prolonged exposure drowsiness). 0.2%-0.4% = 2000-4000ppm (Headaches, fatigue, stagnant, stuffiness, poor concentration, loss of focus, increased heart rate, nausea). 1% is toxic 5% quick death. AIRFLOW Outdoor plants are constantly exposed to natural elements, and that includes wind. Airflow ventilation is one of the often-forgotten environmental factors in healthy cannabis growth and development. Like all environmental factors, we want to “recreate” beneficial stressors that the plant would be exposed to outdoors. Like human bone that becomes stronger in response to stress from resistance we call exercise, stems increase in rigidity and structural integrity in response to stress from air flow. Plants that lack airflow are prone to developing weak stems, leaving them tall, skinny, and unable to hold bud weight as the plant grows. Excessive air flow, on the other hand, which constantly bends the entire plant, could lead to stunted growth or even broken shoots. Thankfully, you don’t need a wind sensor to achieve optimal air flow; a light breeze that just makes the leaves wave or dance gently can assist in the development of strong, dense shoots. A little too much though can stress so be careful not to overdo it too hard for too long as it will eventually stress. Stagnant air within the grow space can also increase the risk of pests, mold, and mildew. Some pests hide under leaves, along stems, and even in the soil itself. A small fan providing a gentle breeze is often enough to prevent a stationary environment, build stem strength, and reduce the chance of pests or pathogens. Proper air circulation and CO2 exchange facilitated by negative pressure contribute to stronger and healthier plants. Good air flow with constant fresh air is essential for maximizing the growth and yield of your indoor plants.. To achieve and maintain negative pressure in your grow tent, several key factors and components come into play. Understanding how these elements work together is essential for creating negative pressure inside your grow tent.Start by selecting an exhaust fan with an appropriate CFM (cubic feet per minute) rating for your specific grow tent size. The CFM rating determines the amount of air the fan can move per minute, and it’s crucial to choose a fan that can sufficiently exchange the air within the tent to create negative pressure. Install the exhaust fan at the highest point in the grow tent to effectively remove warm and stale air from the space. Mounting the fan near the top allows it to expel the warm air, which naturally rises.The negative pressure then automatically draws in fresh air from the lower intake points. Depending on the size and airflow requirements of your grow tent, consider adding a lower intake fan to facilitate controlled air exchange. An intake fan can help regulate the inflow of fresh air and contribute to maintaining balanced pressure within the tent. Want the exhaust higher CFM than lower Intakes, this is what will give us a negative pressure The passive air intake point in the lower portion of the tent allows fresh air to enter passively. Properly positioned and sized passive intake openings ensure a steady flow of fresh air, contributing to the creation of negative pressure when combined with the exhaust fan’s airflow. Co2's density is such gravity pulls it to the bottom 2-3 inches of any enclosure. Adjust passive intake accordingly, and be as close to the floor as possible. I use a 4" intake passive injecting co2 rich air through the 100 gallon, this pours CO2-dense air around plants in a rough 360 degrees arc from a central point, when the main exhaust kicks in and negative pressure goes from the lower intakes will draw air through the rootzones, oxygenation of rootzones, wicking moisture. Keeping RH 40%-45% on exhaust keeping air on the dryer side, now that the plant is big that fan is never off at night but it keeps that air with lots of space for more moisture from the plant and more moisture from the soil. The faster you can cycle water, more nutrients you can uptake. Slight negative pressure is good for maximizing the yield of a growth regime. It makes it easier to control the temperature, humidity, CO2 levels, and other contaminants of the tent. Well, too much of everything is always bad. And the same does for negative pressure as well. So, how would you understand whether the negative pressure exceeded the limit? The simple trick is- if the tent itself seems to pull itself inwards, the negative pressure is still under the tolerable limit. If the pressure gets as high as it bends the poles inwards, that’s where the danger limit starts. So, if you see the poles bend inwards, the negative pressure is something to worry about. Otherwise, if it’s the tent itself if pulled inwards slightly, you don’t have to worry about it. The cohesion-tension theory explains how negative pressure enables water movement from the roots to the leaves of a cannabis plant. As water evaporates from the leaf surfaces through stomata, tension is created, generating a suction force that pulls water upwards through the xylem vessels. This process relies on the cohesive forces between water molecules, forming a continuous column for efficient water transport. In cannabis plants, xylem vessels serve as the conduits for water transport. These specialized cells form interconnected channels that allow water to move upwards from the roots to the leaves. The negative pressure generated through the cohesion-tension mechanism helps drive the water flow within the xylem vessels. Negative pressure facilitates the movement of water from the soil, through the roots, and up to the leaves of cannabis plants. It helps maintain proper hydration and turgor pressure, ensuring the cells remain firm and upright. This is crucial for healthy growth and structural support. Negative pressure transports water and aids in the uptake and transport of dissolved nutrients within the cannabis plant. As water is pulled up through the xylem vessels, essential nutrients and minerals are transported along with it, supplying the various tissues and organs where they are needed for optimal growth and development. ROOTS OXYGEN As well as releasing oxygen created during photosynthesis, plants need to absorb oxygen to perform respiration – i.e. to make energy. Since plant roots are non-photosynthetic tissues that can’t produce oxygen, they get it from air pockets in the soil or grow medium. These air pockets can vary in size based on the makeup of the growing medium, and also on the water saturation levels of the medium. Root oxygenation and soil aeration play an important role in both transpiration and cellular respiration in all plants. This means that plants are highly dependent on the growing medium that holds the optimal amount of oxygen within. Make sure not to overwater, as roots in compacted soil or fully submerged in water with low O2 can cause irreversible damage if left unchecked. This is why even when growing hydroponically, when the roots are submerged in water, it’s important to have an air pump to incorporate adequate O2 to the roots. Grow mediums like coco coir and soils that contain perlite promote aeration and are less prone to overwatering. TEMPS Whether it’s sunlight outdoors or artificial lights indoors, when light heats the air temperature, soil temperature also rises. But it’s not only the air that influences the soil temperature; the grow medium, plant depth, and moisture level can also change how well the soil releases or retains heat. Not all growers monitor soil temperature, but roots are the reservoir system of water and nutrients, and if they are the wrong temperature, things can deteriorate quickly for any plant. Roots are a living part of the plant and therefore have an optimal temperature range in which they thrive at water and nutrient uptake. Although every plant varies, root temperatures above 88°F & below 55°F (above 31°C and below 12°C) can result in stunted growth and ultimately plant death if exposed for too long. 73-76, Avoid going over 77F as common bacterial growth explodes above 77, if disease strikes it's going to strike 10x faster above 77F. WATER Water is one of the most important factors of cannabis growth and development; both transpiration and photosynthesis involve water. Irregular watering can lead to irregular plant growth and development. Too little water and your plant can become dry, brittle, and stressed. Too much water and your plant’s roots can be deprived of important oxygen, and even drown. One of water’s most important purposes is the transportation and movement of nutrients and minerals, which are typically absorbed in the roots and distributed throughout the rest of the plant. The faster the plant can rid itself of water through transpiration the faster it can uptake more water to get more nutrients to where they need to be, by creating a negative pressure we optimize turgor pressure increasing nutrient uptake, by sticking to VPD we optimize transpiration rate and maximize stomatal openings, with sound frequency we open them further. NUTRIENTS Plant growth and development depends on nutrients derived from the soil or air, or supplemented through fertilizer. There are eighteen essential elements for plant nutrition, each with their own functions in the plant, levels of requirement, and characteristics. Nutrient requirements generally increase with the growth of plants, and deficiencies or excesses of nutrients can damage plants by slowing or inhibiting growth and reducing yield. Many deficiencies can be recognized by observing plant leaves. When most people hear the word “fertilizer” they think of synthetic fertilizers, but the word fertilizer refers to any substance or mixture added to soil or a growing medium that increases its fertility or ability to sustain life. Some fertilizers are synthetically produced, and others are mixtures of decomposed organic waste such as worm castings or bat guano (aka bat poop), which are rich in essential nutrients. Plants require eighteen elements found in nature to properly grow and develop. Some of these elements are utilized within the physical plant structure, namely carbon (C), hydrogen (H), and oxygen (O). These elements, obtained from the air (CO2) and water (H2O), are the basis for carbohydrates such as sugars and starch, which provide the strength of cell walls, stems, and leaves, and are also sources of energy for the plant and organisms that consume the plant. Elements used in large quantities by the plant are termed macronutrients, which can be further defined as primary or secondary. The primary nutrients include nitrogen (N), phosphorus (P), and potassium (K). These elements contribute to plant nutrient content, the function of plant enzymes and biochemical processes, and the integrity of plant cells. Deficiency of these nutrients contributes to reduced plant growth, health, and yield; thus they are the three most important nutrients supplied by fertilizers. The secondary nutrients include calcium (Ca), magnesium (Mg), and sulfur (S). The final essential elements are used in small quantities by the plant, but nevertheless are necessary for plant survival. These micronutrients include iron (Fe), boron (B), copper (Cu), chlorine (Cl), Manganese (Mn), molybdenum (Mo), zinc (Zn), cobalt (Co), and nickel (Ni). 18 elements essential for plant nutrition, and classify the essential elements as macronutrients or micronutrients. Macronutrients: used in large quantities by the plant Structural nutrients: C, H, O Primary nutrients: N, P, K Secondary nutrients: Ca, Mg, S Micronutrients: used in small quantities by the plant Fe, B, Cu, Cl, Mn, Mo, Zn, Co, Ni Nitrogen: found in chlorophyll, nucleic acids, and amino acids; component of protein and enzymes. Phosphorus: an essential component of DNA, RNA, and phospholipids, which play critical roles in cell membranes; also plays a major role in the energy system (ATP) of plants. Potassium: plays a major role in the metabolism of the plant, and is involved in photosynthesis, drought tolerance, improved winter hardiness, and protein synthesis. Nitrogen availability limits the productivity of most cropping systems in the US. It is a component of chlorophyll, so when nitrogen is insufficient, leaves will take on a yellow (chlorotic) appearance down the middle of the leaf. New plant growth will be reduced as well and may appear red or red-brown. Because of its essential role in amino acids and proteins, deficient plants and grains will have low protein content. Nitrogen excess results in extremely dark green leaves, and promotes vegetative plant growth. This growth, particularly of grains, may exceed the plant's ability to hold itself upright, and increased lodging is observed. Nitrogen is mobile both in the soil and in the plant, which affects its application and management, as discussed later. Phosphorus is another essential macronutrient whose deficiency is a major consideration in cropping systems. It is an essential part of the components of DNA and RNA, and is involved in cell membrane function and integrity. It is also a component of the ATP system, the "energy currency" of plants and animals. Phosphorus deficiency is seen as purple or reddish discolorations of plant leaves, and is accompanied by poor growth of the plant and roots, reduced yield and early fruit drop, and delayed maturity. Phosphorus excess can also present problems, though it is not as common. Excess P can induce a zinc deficiency through biochemical interactions. Phosphorus is generally immobile in the soil, which influences its application methods, and is somewhat mobile in plants. Potassium is the third most commonly supplemented macronutrient. It has important functions in plant metabolism, is part of the regulation of water loss, and is necessary for adaptations to stress (such as drought and cold). Plants that are deficient in potassium may exhibit reductions in yield before any visible symptoms are noticed. These symptoms include yellowing of the margins and veins and crinkling or rolling of the leaves. An excess, meanwhile, will result in reduced plant uptake of magnesium, due to chemical interactions. The mobility of a nutrient in the soil determines how much can be lost due to leaching or runoff. The mobility of a nutrient in the plant determines where deficiency symptoms show up. Nutrients that are mobile in the plant will move to new growth areas, so the deficiency symptoms will first show up in older leaves. Nutrients that are not mobile in the plant will not move to new growth areas, so deficiency symptoms will first show up in the new growth. Nutrient mobility varies among the essential elements and represents an important consideration when planning fertilizer applications. For instance, NO3- nitrogen is very mobile in the soil, and will leach easily. Excessive or improper application increases the risk of water contamination. Meanwhile, phosphorus is relatively immobile in the soil and is thus less likely to runoff. At the same time, it is also less available to plants, as it cannot "migrate" easily through the soil profile. Thus, P is often banded close to seeds to make sure it can be reached by starting roots. Nutrients also have variable degrees of mobility in the plant, which influences where deficiency symptoms appear. For nutrients like nitrogen, phosphorus, and potassium, which are mobile in the plant, deficiency symptoms will appear in older leaves. As new leaves develop, they will take the nutrients from the old leaves and use them to grow. The old leaves are then left without enough nutrients, and display the symptoms. The opposite is true of immobile nutrients like calcium; the new leaves will have symptoms first because they cannot take nutrients from the old leaves, and there is not enough in the soil for their needs. In general, plant nutrient needs start low while the plants are young and small, increase rapidly through vegetative growth, and then decrease again around the time of reproductive development (i.e., silking and tasseling). While absolute nutrient requirements may be low for young plants, they often require or benefit from high levels in the soil around them. The nutrient status of the early seedlings will affect the overall plant development and yield. Plants entering the reproductive stages have high nutrient requirements, but many of these are satisfied by redistributing nutrients from the vegetative parts. Nitrogen: nitrate (NO3-) and ammonium (NH4+) Phosphorus: phosphate (HPO42- and H2PO4-) Potassium: K+ Calcium: Ca2+ Magnesium: Mg2+ Sulfur: sulfate (SO4-)