Re-vegging, short for re-vegetation, refers to the process where a cannabis plant that has already started flowering re-enters the vegetative stage. Most cannabis plants are photoperiod strains, meaning they require long nights (typically 12 hours of uninterrupted darkness) to initiate flower/bud production. When these plants receive light during their dark period, even if it's just a small amount like a blinking LED in a grow tent, they can respond by re-vegging. Re-vegging is triggered when a flowering plant experiences light exposure during its 12-hour dark period. Even a few interrupted nights or a minor light leak can initiate the re-vegging process. The plant undergoes significant internal changes during this period, resulting in various leaf symptoms and altered growth patterns.

Aphids, also known as greenflies and blackflies, are soft-bodied insects that can be found on cannabis plants worldwide. They come in various colors, including white, green, yellow, black, brown, and red, depending on their life stage and habitat. Adult aphids are bigger and rounder, while young aphids (nymphs) are smaller and thinner. They tend to form colonies on the undersides of stems and leaves.

Barnacle scales, also known as wax scales, are unusual bugs that can be found on the stems and under the leaves of plants. These scale insects attach themselves to the plant and remain stationary once they find a favorable spot. They resemble round growths or bugs and have a tendency to steal energy from the plant. Scale infestations can weaken plants and may lead to the release of a sweet sticky substance called "honeydew," which can attract ants and cause sooty mold to develop on the plant.

A boron deficiency in cannabis is relatively uncommon, except when the plant is not receiving sufficient water or is exposed to extremely dry conditions. Typically, it coincides with other nutrient or pH issues, manifesting as leaf problems. The initial signs of a boron deficiency include unusual or thick growth tips and the development of brown or yellow spots on new leaves. New growth in affected marijuana plants may exhibit dark patches, indicating the onset of a boron deficiency. Additionally, upper cannabis leaves may exhibit abnormal growth, slow growth, twisted growth, or even die off. Wrinkled or curled leaves may also be observed. Roots may display unhealthy or stunted growth, and stems can become rough or hollow. It's worth noting that a boron deficiency may resemble a calcium deficiency since boron is necessary for the plant to properly utilize calcium. New growth is primarily affected, displaying a burnt or scorched appearance. Furthermore, a boron deficiency often coincides with apparent deficiencies in potassium or nitrogen, as these nutrients are essential for boron utilization by the plant.

Broad mites are minuscule pests that infest cannabis plants, making them incredibly difficult to spot without magnification. Even under a microscope, they are challenging to detect. Their size and elusive nature often lead to confusion with other plant issues such as heat stress, overwatering, pH imbalance, or root problems. The symptoms they cause are not uniform throughout the plant but concentrated in specific areas of infestation. Twisted or drooping new growth, blistered or "wet" looking leaves, and upward curling of leaf edges are common signs. During the flowering stage, buds may become sickly and die.

Cannabis bud rot, also known as "Big Bud Disease" or "The Curse of the Successful Grower," is a fungal infection that targets mature, large buds nearing harvest time. This affliction can be devastating, as it attacks and kills the most substantial and dense buds. The initial indication of bud rot often manifests as a sudden yellowing of the surrounding leaves, occurring within 1-2 days. The rot usually originates from the base of these discolored leaves, where the bud begins to decay. Bud rot, or Botrytis cinerea, affects certain areas of the colas, primarily targeting bigger and denser buds. Outdoors, it can spread across the entire plant, particularly after periods of rainfall.

Calcium is an essential nutrient for cannabis plants, providing structural support and aiding in stress resistance, particularly heat. A calcium deficiency in cannabis can be identified by the presence of brown or bronze splotches or spots on the leaves. While yellowing is commonly associated with calcium deficiency, it may not always occur. Under LED lights, the splotches may even appear purple. Calcium deficiencies are often caused by low pH at the roots or by using soft or filtered water.

Caterpillars can be a frustrating problem when growing cannabis outdoors. They leave behind visible signs such as missing leaf chunks and clumps of caterpillar droppings on the leaves. Spotting caterpillars in action can be infuriating. However, there are effective ways to combat these pests and protect your cannabis plants.

A cannabis copper deficiency is characterized by dark leaves with blue or purple undertones. The tips and edges of the leaves turn pale yellow or white, creating a stark contrast with the rest of the darkened foliage. In addition, the affected leaves may exhibit a shiny or metallic sheen, feel stiff, and start turning under. This deficiency tends to affect the leaves directly under the grow lights.

Crickets, including tree crickets and mole crickets, can be pests for cannabis plants, causing small holes in leaves and disturbing the roots. While crickets are not as common of a problem as grasshoppers, it is important to address their presence before they multiply in numbers. Tree crickets are known to chew on cannabis leaves, while mole crickets tunnel under the plants.

The four-lined plant bug, scientifically known as Poecilocapsus lineatus, is a common pest that affects cannabis plants in the United States. This pest is characterized by its distinct black lines against a yellow-to-green background. The adults have an orange head with dark reddish-brown eyes. Both male and female adults share similar features, although females are slightly larger and broader, particularly in the abdomen. These bugs primarily feed on the sap of the plant, causing damage to the leaves.

Fungus gnats are small, mosquito-like flies that can be found buzzing around cannabis plants, particularly around the soil. They are often a result of overwatering, as their larvae thrive in wet soil. These tiny pests can cause damage to the roots of cannabis plants, leading to slowed growth and even plant death, especially in young seedlings. Fungus gnats are dark brown or black in color and measure about 2 mm in length.

Crickets, including mole crickets and tree crickets, can pose a threat to cannabis plants by eating holes in the leaves or tunneling under the plants' roots. While crickets are not as common of a problem as grasshoppers, it's important to address the issue before their population grows.

When cannabis plants are exposed to excessive heat and light, they can suffer from stress, which manifests as various symptoms on the leaves. Signs of stress include yellow or brown spotting, burned areas, leaf curling (either up or down), folding inward resembling cones or tacos, and serrated leaf edges flipping up. Additionally, high temperatures and low humidity can lead to dry, crispy leaves.

Hemp russet mites are tiny bugs that infest cannabis plants, often residing in the crevices of leaves, stems, or buds. They are difficult to spot unless there is a significant infestation. Initially, the symptoms may be mistaken for other issues like mold, pollen, or nutrient deficiencies. The leaves may exhibit curling on the edges, and buds can start to wither. The mites themselves appear as beige or yellow masses, usually concentrated towards the top of the plant. An intense infestation can cause the affected parts of the cannabis plant to turn beige or yellow. Infected plants may also experience drooping, dull-colored leaves and stems, as well as the presence of brown or yellow spots. Identifying hemp russet mites can be challenging due to their microscopic size.

Cannabis plants can exhibit both male and female characteristics, resulting in what growers refer to as hermaphrodite or "hermie" plants. This occurrence is known as hermaphroditism, where male pollen sacs and female flowers grow on the same plant. The presence of "bananas" or elongated stamens among the pistils of the buds is another sign of hermaphroditism. Hermies can be triggered by stress, such as heat or excessive light, but can also be a genetic trait inherent in certain strains. It is advisable to remove hermaphrodite plants promptly to prevent pollination, as the pollinated buds will produce seeds.

A cannabis iron deficiency is characterized by the appearance of bright yellow new leaves, which can sometimes coincide with other nutrient problems or deficiencies in cannabis plants. This deficiency is often caused by issues with pH levels, particularly when the pH at the roots is too high. However, it can also be triggered by environmental stress, with the symptoms resolving on their own after the stressful period ends. The yellowing of new leaves, especially their bright yellow or almost white coloration, is the prominent sign of an iron deficiency. In some cases, the affected yellow parts of the leaves may gradually turn green as the plant continues to grow, starting from the tips and moving towards the base. It's worth noting that while an entire yellow leaf can eventually regain a green and healthy appearance, this ability is unique to iron deficiencies compared to most other nutrient deficiencies. Although a cannabis iron deficiency may resemble a magnesium deficiency, it primarily affects newer, upper, and inner leaves, while magnesium deficiency tends to impact older and lower leaves.

Leaf miners are pests that live inside the tissue of leaves, causing damage as they tunnel through and consume the nutritious parts. The resulting trails or markings on the leaves are distinctive indicators of leaf miner activity. These pests are not a specific bug species but rather the larvae of various insects, including moths, sawflies, flies, and beetles. Despite the different parent bugs, the leaf markings caused by leaf miners exhibit similarities.

Leaf Septoria, also known as "yellow leaf spot," is a fungal or bacterial condition that affects cannabis plants, particularly in warm and wet weather. The symptoms usually start appearing on the lower leaves of the plant. These spots often have darkened borders and a hard growth in the center resembling a small pimple. What sets them apart is their uniformity, appearing as little circles with tiny dark specks (spores) at their centers. Initially yellow, the spots gradually turn brown over time.

Leafhoppers are common pests for outdoor cannabis growers. They belong to the insect family Cicadellidae and come in various species, including the Graphocephala coccinea, also known as the "candy-striped," "red-banded," "scarlet and green," or "red and blue" leafhopper. These colorful insects can be found on cannabis plants in North and Central America. Leafhoppers feed on the plant's sap and may leave spots on the leaves. The potato leafhopper, in particular, can cause a disorder called "hopperburn," which leads to the death of leaf ends. Leafhoppers can also transmit plant diseases like beet curly top virus.

When cannabis plants are exposed to excessive light, they can experience light burn or light stress. This occurs when the plants receive more light than they can handle, leading to various symptoms such as yellowing leaves, burnt tips, and upward leaf curling. Light burn is often observed on the top leaves closest to the grow lights, while older leaves can also be affected if exposed for a prolonged period. The condition can be mistaken for a nitrogen deficiency, but light-burned leaves are harder to pluck off compared to nitrogen-deficient ones.

A cannabis magnesium deficiency is characterized by the appearance of light green or yellow coloring on the veins and edges of lower and older leaves. This discoloration is often accompanied by red stems. Magnesium, being a mobile nutrient, can be transferred from older leaves to newer ones within the plant. Therefore, a deficiency typically manifests in the lower parts of the plant and affects older, less vital leaves. The affected leaves may exhibit yellowing or bright green coloration, with a crispy texture along the edges. It's important to note that this crispiness is distinct from nutrient burn, as it doesn't extend into the inner leaf areas. In some cases, red stems may also be observed, although this isn't always present. As the deficiency worsens, light brown spotting might appear within the margins or along the leaf edges, although this can also be indicative of other deficiencies that often occur alongside magnesium deficiency.

When your marijuana plant is experiencing a manganese deficiency, you may notice the leaves turning yellow between the veins, accompanied by mottled brown spots. These brown patches can spread and ultimately cause the affected leaves to wither and die. In some cases, the leaves may even shred and disintegrate. The overall growth of the plant may also be stunted, with the yellowing starting at the base of the leaves and gradually extending towards the tips.

Mealybugs are white, hairy insects that thrive in warm temperatures and dislike the cold. They can even persist and spread on drying cannabis plants after harvest, so it's crucial to remain vigilant. These pests often leave behind white patches resembling mold, powder, or webbing, which can be mistaken for white powdery mildew (WPM). Mealybugs also secrete a sugary liquid known as honeydew, which can attract ants and lead to the growth of sooty mold on the leaves.

The initial symptoms of a molybdenum deficiency in plants, such as cannabis, may resemble those of a nitrogen deficiency, including yellowing of older, lower leaves. However, a distinct characteristic of molybdenum deficiency is the appearance of a unique orange, red, or pink color around the edges of the leaves, which may gradually move toward the center or even manifest in the middle of the leaves.

A cannabis nitrogen deficiency is characterized by the yellowing and wilting of the older, lower leaves on the plant. These leaves may turn crispy and eventually fall off. The plant may appear pale or lime-colored, lacking the vibrant green color typically associated with healthy growth. Nitrogen deficiency primarily affects the oldest, lowest leaves, although in some cases, the entire plant may become light colored.

Marijuana plants experiencing nitrogen toxicity display a set of characteristic symptoms. The leaves appear dark green and shiny, and they develop a claw-like shape with bent ends. This clawing effect is unique to nitrogen toxicity and is often mistaken for overwatering. As the condition progresses, the affected leaves may turn yellow and eventually brown before falling off. It's important to note that yellowing caused by nitrogen toxicity is distinct from other nutrient deficiencies, as the rest of the plant remains dark green.

Nutrient burn, also known as fertilizer burn, is a common issue encountered by beginner cannabis growers. It occurs when the cannabis plant's roots absorb an excessive amount of nutrients, leading to disrupted water flow and resulting in burnt tips on the leaves. The burn initially appears as yellow or brown tips and can progress inward, causing the ends of leaves to become crispy and twisted. Nutrient burn is more serious during the flowering stage of the plant.

Overwatering is a common issue faced by cannabis growers, leading to drooping plants with curled-down leaves. It can occur when plants receive excessive water or when watering frequency is too high, causing the roots to sit in stagnant water. Over time, overwatered plants may exhibit chlorosis, which is leaf yellowing resembling a nitrogen deficiency. The symptoms are especially prominent in young plants and seedlings. The roots of cannabis plants require oxygen, and overwatering restricts their access to it, resulting in the drooping appearance.

Managing pH levels is vital for the healthy growth of cannabis plants, as it enables the roots to effectively absorb essential nutrients. Fluctuations in pH around the root zone can lead to stress in the plant, manifesting as the appearance of brown spots on the leaves. While this issue is more commonly observed in hydroponic setups due to pH fluctuations, it can also occur in soil-based cultivation. The occurrence of these spots is often associated with pH levels swinging too high or low.

A cannabis phosphorus deficiency primarily affects the lower and older leaves of the plant. These leaves may exhibit dark green or yellow discoloration, accompanied by brown, bronze, or blue spots and splotches. The affected leaves can become thickened and curled, appearing stiff. In some cases, the stems of the plant may turn bright red or purple, though not always. It's worth noting that a phosphorus deficiency can sometimes be accompanied by a calcium deficiency since these two nutrients interact within the plant. This deficiency is more commonly observed after the plant starts forming buds, as phosphorus demands increase during this stage.

Planthoppers pose a threat to cannabis plants as they can attack and infest them, causing damage and potentially spreading plant diseases. These pests leave behind a distinctive cotton-like growth while they extract vital nutrients from the plants. The appearance of this white fuzzy growth, often mistaken for mold or powdery mildew, is actually a secretion produced by the planthoppers themselves. These insects go through different life stages, with the nymphs and larvae also producing the white waxy secretions for protection. Adult planthoppers can vary in color but generally have a shape that mimics a leaf or other parts of a plant.

A cannabis potassium deficiency primarily manifests in the form of symptoms observed on older leaves, although it may also affect the top of the plant. Affected leaves display yellow, brown, or burnt edges and tips. These symptoms may resemble nutrient burn, but with a potassium deficiency, the affected leaves also show yellowing in the margins. The veins inside the leaves generally remain green.

Cannabis plants with root problems can exhibit various symptoms that indicate their distressed state. Overwatering is a common cause, leading to symptoms such as the plant appearing droopy or overwatered, curling or cupping of leaves, wilting of individual stems or the entire plant, slow growth or stunted size, yellowing or discoloration of leaves (which may even manifest as purple or red), brown or burnt spots on leaves, and other nutrient-related issues. Brown or slimy roots often indicate the presence of root rot, which emits a foul odor when present in the runoff water. As the root problems progress, leaves may start dying and falling off rapidly, and the plants may exhibit reduced water consumption.

Cannabis root rot is a condition characterized by slimy, brown, twisted, or unhealthy roots. It occurs due to the presence of unwanted pathogens in the hydroponic tank. The roots affected by root rot are unable to provide adequate oxygen to the plant, resulting in curled, drooping, and unhealthy leaves. The symptoms of root rot often resemble those of over or under-watering in soil-grown plants.

Slugs and snails can be troublesome pests for cannabis plants. They leave behind a trail of slime on the leaves and create holes with scalloped edges, often mistaken for caterpillar damage. These nocturnal invaders primarily target the tender leaves and buds of the plants, posing a threat to their health and growth. Their damage can be quite extensive if their numbers increase.

Spider mites are a type of mite that belongs to the same family as spiders, ticks, and other mites. They are common pests that can infest cannabis plants and are notoriously difficult to eliminate. The first sign of spider mite damage is the presence of tiny specks or bite marks on the leaves, which appear as tiny specks or discoloration.

Stink bugs, a diverse group of insects, have been known to pose a threat to cannabis plants. They exhibit distinctive behavior such as laying clusters of white eggs, which later hatch into small beetle-like insects. As they progress through their life stages, stink bugs undergo physical transformations, displaying variations in appearance from nymphs to adults. Notably, stink bugs possess a pungent odor, making them all the more bothersome.

A sulfur deficiency in plants is a relatively uncommon occurrence. It becomes evident through a condition known as all-over chlorosis, which refers to the yellowing of leaves. Initially, the newer leaves are affected, often resembling symptoms of a nitrogen deficiency. However, there are distinct differences that set sulfur deficiency apart. Notably, the discoloration may progress to a pinkish red or orange hue on the undersides of leaves. Additionally, the buds on flowering plants might begin to wither. Unlike most deficiencies that cause leaf yellowing starting from the tips, sulfur deficiency starts at the back of the leaf and gradually moves forward.

Thrip damage on cannabis plants can be identified by several characteristics. Adult thrips are small and agile insects, while their young counterparts resemble pale, motionless worms on the leaves. The appearance of thrips can vary depending on their life stage and geographical location, ranging from dark or golden-winged insects to worm-like nymphs. Thrips feed on cannabis leaves by piercing them with their mouthparts and extracting nutrients, resulting in distinctive marks on the foliage. These marks are shiny and can give the impression of being slimy. They appear as silver or bronze spots that are larger and more irregularly shaped than the bites left by spider mites. If left untreated for a prolonged period, the affected leaves may eventually wither and die. It's worth noting that while thrip damage might not be accurately portrayed in pictures, in real-life observations, it has been described as resembling "dried spit" or tiny snail trails.

Tobacco Mosaic Virus (TMV) is a virus commonly found in tobacco plants. It causes splotchy or twisted leaves, mottling symptoms (resembling a "mosaic" pattern), slowed growth, and reduced yields. TMV has been detected in cannabis plants, along with other mosaic viruses like cucumber mosaic virus and alfalfa mosaic virus. However, widespread transmission of mosaic viruses in cannabis plants hasn't been extensively documented. Some infected plants may not show visible symptoms, and some seemingly healthy plants may still carry the virus.

If your cannabis plant is drooping, it could be a sign of either overwatering or underwatering. In this case, we will focus on the symptoms and solutions for underwatering. When a plant is underwatered, it may display certain characteristics. The leaves tend to feel "papery" and thin since they lack water content. In contrast to overwatering, where the leaves feel bloated and swollen, underwatered leaves may become yellow and show signs of nutrient deficiencies. Underwatering can cause seedlings to have dry growing mediums and papery leaves, while larger plants may experience wilting and drooping.

White Powdery Mildew, also known as White Powdery Mold or WPM, is a fungus that can infest cannabis plants. It appears as white patches of powdery growth on the leaves and stems, resembling flour. If left untreated, it can spread rapidly and cause damage to the plant, rendering the affected buds unusable.

Whiteflies are small, white insect pests that resemble tiny moths when in flight. They typically congregate underneath the leaves of plants, including cannabis, and feed on essential nutrients, causing white spots to appear on the upper side of the leaves. While the actual leaf damage may not be immediately noticeable, the presence of these fluttering insects, which are approximately 2 mm long, is easily detectable to the naked eye. When disturbed, whiteflies will take flight.

Indoor cannabis growers commonly utilize fans to create a pleasant and breezy environment for their plants. However, it is essential to be cautious, as excessive wind can lead to certain issues. When marijuana plants are subjected to too much breeze, their leaves may suffer from wind burn. Wind-burned leaves typically exhibit a clawed appearance, with their tips curling downwards. While clawed leaves can resemble symptoms of overwatering, underwatering, or nitrogen toxicity, wind burn is identified when the leaves in close proximity to the fan exhibit this clawed shape while leaves farther away remain unaffected. Additionally, high levels of wind can cause unusual problems, such as the development of brown or bronze spots on affected leaves, resembling burn marks. These spots occur due to the leaf's inability to perform its normal functions.

A cannabis zinc deficiency is characterized by yellowing of the younger leaves between the veins, discoloration and dying of leaf tips, a banded appearance on the leaves, and stunted vertical growth. If the deficiency persists, the flowers of a budding plant may stop growing or even die.