UnderGrow

Grower's manual

Everything you need to know to grow well: germination, watering, light, nutrients, pests, harvest, drying, curing and the most famous strains. Explained simply, with UnderGrow art.

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Grower's manual

Growing

From seed to harvest: germination, stages, light, watering, nutrients and climate.

Germinate in paper towelThe best-known way to germinate: the seed goes between two damp (not soaked) paper…Germinate in a glass of waterThe seed goes in a glass of warm water (preferably chlorine-free: boiled and cooled…Straight into soilPlanting the seed directly in its pot (or in the garden soil), without germinating it…SeedlingThe seedling is the baby plant: from the moment it pokes out of the soil until it has 3…VegThe stage where the plant builds its structure: stem, branches, leaves and root. It…Pre-flowerThe transition between growing and flowering. The plant "realizes" it has to reproduce:…FloweringThe stage where the plant makes its flowers. In cannabis, the buds are clusters of female…Ripening and harvestThe end of flowering: the buds stop growing and finish ripening. The grower picks the…The light timer (18/6 and 12/12)The timer turns the lamp on and off on a schedule. It is written "18/6" for 18 hours of…Health and stressHealth is how the plant is doing: firm green leaves, even growth. Stress is the sum of…How to waterThe root needs two things at once: water and air. Good soil is like a sponge: after…Indoor climate and its equipmentThe plant doesn't regulate its temperature: it lives at the air's. Temperature decides…NutrientsThe plant makes its own food with light, water and air (photosynthesis), but it needs…PH and nutrient lockoutA scale from 0 to 14 that measures how acidic or alkaline something is. 7 is neutral;…Thermo-hygrometerA little device that measures temperature (thermometer) and the air's relative humidity…PH meterAn electronic meter (pH meter) with a glass probe that goes in the water and shows the pH…Ec meterElectrical conductivity: how much electricity the water conducts. Pure water barely…Par meterNot all light is equally useful: plants use the light from blue to red, called "par"…PH downA liquid acid that lowers the pH of the watering water. The most common ones are…Wick wateringAn irrigation system with no pump or electricity: a rope (cotton, nylon or acrylic) runs…Drip irrigationA network of hoses with emitters: tiny parts that let water out drop by drop, always the…Batch growingA batch is a group of plants treated as one unit: same strain, sown on the same day, with…The seasonsThe earth is tilted: for half a year one hemisphere gets the sun more head-on (summer,…The climate of your provinceA place's climate is how the weather behaves through the year: how hot it gets in summer…Rain, storm and hailIt waters for free and with soft water, with a pH close to 6. But in flowering it's a…FrostsWhen the temperature drops below 0 °C, the water inside the leaves freezes, ice crystals…

Problems

Pests, fungi, deficiencies and mistakes: how to spot them and what to do.

ThirstThe plant runs out of water in the soil. Without water it can't keep its leaves firm…OverwateringToo much water in the soil for too long. The problem isn't the water itself, but that it…Nitrogen deficiencyThe plant doesn't have enough nitrogen (n), the nutrient it uses the most. It uses it to…Nutrient burnToo much fertilizer. Nutrients are salts: when there are too many in the soil, they…HeatStress from high temperature. Above 28-30 °C the plant loses water faster than the root…Spider miteA mite (related to spiders, not an insect) half a millimeter long, almost invisible to…Powdery mildewA fungus that grows on the leaves like a white powder, looking like flour. It covers the…WhiteflyA tiny insect (1 to 2 mm), white, with wings, related to aphids. It lives under the…ThripsVery thin, elongated insects (1 mm) that rasp the leaf surface and suck up what oozes…Calcium deficiencyIt's short on calcium (ca). Calcium is part of every cell wall: without it, new tissue…Magnesium deficiencyIt's short on magnesium (mg). Magnesium sits at the center of every chlorophyll molecule:…Light burnToo much light right under the lamp. A leaf has a limit on how much light it can use;…BotrytisGray mold: a fungus that rots the buds from the inside out. It's flowering's worst…HermaphroditeA female plant that grows male flowers. Cannabis has male and female plants, but under…

Remedies

The remedies for each pest and fungus, and how to use them.

Potassium soapA soap made with vegetable oils and potassium (not kitchen detergent, which damages the…SulfurA yellow mineral used for centuries against fungi, especially powdery mildew. It is sold…Neem oilAn oil pressed from the seeds of the neem, a tree from India. It is a natural insecticide…Bloom fertilizer (flowering)A fertilizer with a lot of phosphorus (p) and potassium (k) and almost no nitrogen. It is…Cal-magA supplement of calcium (ca) and magnesium (mg), almost always with a little iron. These…Remove rotten budsThe only way to stop botrytis (gray mold) once it appears: remove the rotten bud. There…Remove male flowersRemoving by hand the male flowers that a female has grown, before they release pollen and…Raise the lampMoving the lamp away from the plant tops. Light drops very fast with distance: if you…

Techniques

Pruning and training so the plant yields more.

ToppingCutting off the main tip of the plant ("topping"), right above a node. Two new branches…FIMA prune of the main tip. Instead of cutting the whole shoot (as in apical), about 70-80 %…LST (tie and bend)LST stands for "low stress training". You gently bend the main stem and the branches and…DefoliationRemoving big leaves (the "fan leaves") from the lower and middle part of the plant. It is…Clone trayA tray with a clear dome (a mini greenhouse) where rooted clones wait before going to…ClonesA clone (or cutting) is a branch cut from a plant and set to grow its own roots. The new…

Harvest and curing

Harvesting, drying and curing well: what defines the final quality.

Trichomes and harvest pointTrichomes are microscopic hairs with a little resin head, like pins with a drop on the…Wet trimmingTrimming means removing the leaves that surround the bud: the big ones (fan leaves) and…Hang whole (dry trimming)The whole plant or individual branches are cut, only the big leaves are removed, and it…DryingRemoving most of the water from the freshly cut bud (it has about 75 %). It seems like a…CuringKeeping the dry buds in closed containers for weeks so they finish ripening. It is like…Mold in drying or in the jarFungi that grow on the buds when there is too much moisture, either while drying or…Humidity packsPacks with a salt and water solution inside, in a membrane that lets moisture through: if…

Strains

The most famous strains: where they come from and how to grow them.

Males and femalesCannabis is a "dioecious" plant: there are male plants and female plants. Only females…Colloidal silverWater with very fine silver particles in suspension. Sprayed on a female, it blocks…The pollen jarPollen is a fine yellowish powder released by male flowers. Each grain carries half of…The crossPollinating a female of one strain with pollen from another plant. The seeds that come…Your seeds: f1, f2, f3...The first cross between two different strains is called f1 ("filial 1"). Its daughters…Northern Lights AutoThe autoflower version of Northern Lights, one of the most famous strains in history. It…Critical AutoThe autoflower version of critical, one of the most grown strains in europe.Amnesia Haze AutoThe autoflower version of Amnesia Haze, a classic Sativa from the Amsterdam coffeeshops.…White Widow AutoThe autoflower version of White Widow, named for the layer of trichomes that leaves it…Gorilla AutoThe autoflower version of gorilla glue, famous for being one of the stickiest plants out…Blueberry AutoThe autoflower version of blueberry, famous for its fruity aroma and the bluish and…Purple Kush AutoThe autoflower version of purple Kush, a pure Indica known for its dark purple buds.Lemon AutoAn autoflower from the "lemon" family: Sativa-leaning strains bred to have an intense…Tangie AutoThe autoflower version of tangie, a Sativa famous for its freshly peeled tangerine aroma.Cherry AutoAn autoflower from the cherry family: strains with a cherry aroma and reddish buds, like…Skunk #1One of the most important strains in history: it was one of the first stable hybrids, and…Afghan KushAn "earth" Indica (landrace): a wild strain that formed on its own over centuries in one…Super Silver HazeSuper Silver Haze: a legendary 90s Sativa from the Haze family, the sativas with an…Northern LightsThe original Northern Lights: a classic Indica, one of the most awarded and most grown in…Amnesia HazeAmnesia Haze: one of the most famous sativas in the Amsterdam coffeeshops, known for its…Jack HererA dutch Sativa named after Jack Herer, an american activist who wrote a famous book on…Durban PoisonA "landrace" Sativa from south africa, one of the few pure sativas grown today almost…Big BudAn Indica bred with a single goal: yield. The name ("Big Bud") says it all.Og KushOne of the most influential strains from the u.s. West coast. Hundreds of modern strains…White WidowWhite Widow: the plant that looks white from so many trichomes. One of the best sellers…Granddaddy PurpleGranddaddy Purple ("grandfather purple"): a California Indica with intense purple buds…Purple HazeA Sativa from the Haze family with purple tones. Its name comes from jimi hendrix's song…Blue DreamA California hybrid that for years was among the best sellers in u.s. Dispensaries.Agent OrangeA hybrid with an intense orange aroma, bred in the united states by the seed bank tga (by…Black DominaA heavy Indica, with leaves so dark they look black, lots of resin and a hashish aroma.Strawberry CoughA Sativa with a strawberry aroma, highly sought for its scent. The name ("Strawberry…Cherry PieA californian hybrid with a Cherry Pie aroma and buds in reddish and purple shades.Lemon HazeA Sativa of the Haze family with an intense lemon aroma.Frisian DewA hybrid bred specifically for outdoors in cool, damp climates, with purple and reddish…GelatoA modern hybrid from San Francisco, from the "dessert" strains: sweet, creamy aromas and…Ak-47 AutoThe autoflower version of ak-47, one of the most awarded strains from holland. Despite…Skunk #1 AutoThe classic Skunk #1 as an autoflower: one of the most stable genetics there is, now in a…Afghan Kush AutoA pure mountain Indica as an autoflower: small, sturdy and one of the fastest in the…Big Bud AutoBig Bud as an autoflower: an Indica made to give fat, heavy buds.Jack Herer AutoJack Herer as an autoflower: a classic Sativa, active and aromatic, in a plant that…Blue Dream AutoBlue Dream as an autoflower: high-yielding, aromatic and one of the best sellers.Sour Diesel AutoSour Diesel as an autoflower: the fuel-smelling Sativa, in a fast plant.Zkittlez AutoZkittlez as an autoflower: an Indica that tastes like fruity candy, with purple buds.Og Kush AutoOg Kush as an autoflower: California's most famous strain, in a plant that flowers on its…Girl Scout Cookies AutoGirl Scout Cookies as an autoflower: very potent and covered in resin.Gelato AutoGelato as an autoflower: a 'dessert' strain, sweet and creamy, in a fast plant.Wedding Cake AutoWedding Cake as an autoflower: so covered in resin it looks frosted.Pineapple Express AutoPineapple express as an autoflower: a tropical Sativa that smells like pineapple.Bruce Banner AutoBruce banner as an autoflower: one of the most potent, named after the man who turns into…Purple Punch AutoPurple punch as an autoflower: a sweet Indica with deep purple buds.Durban Poison AutoDurban Poison as an autoflower: a pure african Sativa, very active.Mimosa AutoMimosa as an autoflower: a citrus Sativa that smells like orange, very expensive.Runtz AutoRuntz as an autoflower: the trendy strain, that tastes like candy.Do-Si-Dos AutoDo-si-dos as an autoflower: a very potent Indica, with dark purple buds.Super Silver Haze AutoSuper Silver Haze as an autoflower: an award-winning Sativa, in a plant that flowers on…TrainwreckA classic Sativa from northern California, fast for its kind and very high-yielding.Sour DieselThe fuel-smelling Sativa: one of the most famous strains in the united states.Girl Scout CookiesGirl Scout Cookies (GSC): one of the most influential strains of recent years, very…Wedding CakeA hybrid so covered in resin it looks frosted. One of the most popular of recent years.ZkittlezAn Indica that tastes like fruity candy, winner of several awards.RuntzThe trendy strain: sweet as candy, very striking and one of the most expensive.ChemdawgA legend with a unique chemical aroma: the grandmother of Sour Diesel and Og Kush.Malawi GoldA pure african Sativa ('landrace'): a strain of origin, that has grown the same way for…Acapulco GoldA mexican legend: a pure Sativa of origin, famous since the 60s for its golden buds.Panama RedA pure Sativa of origin, very rare, with reddish pistils and buds.

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