Quick answers · 164 questions
The questions growers ask most, answered.
One question per page: the answer in the first few lines, the numbers that matter, what to do next and the sources. Each links to the full article when you want the depth.
Basics26
- Can I flower a photoperiod plant 12/12 from seed?Yes, a photoperiod plant can be grown 12/12 from seed, but it won't flower straight away: it first has to mature, forming its first single flowers at around the 7th node, typically after 3–5 weeks.How-to · Supported
- Can I grow autoflowers and photoperiods in the same tent?You can grow autoflowers and photoperiods in the same tent, but one schedule must lose.How-to · Grower practice
- Can I grow cannabis in a closet or cupboard?Yes, you can grow cannabis in a closet or cupboard if it can be made light-tight, ventilated and safely powered.How-to · Grower practice
- Can I grow seeds I found in my weed?You can grow seeds found in your weed, but bag seed is a gamble.How-to · Grower practice
- Can you clone an autoflower?You can root a cutting from an autoflower, but it is impractical.How-to · Grower practice
- How long do autoflowers take from seed to harvest?Autoflowers usually take about 9–14 weeks from sprouting to harvest, with fast lines near week 9–10 and long lines near week 13–14.Numbers · Grower practice
- How many plants can I fit in my grow tent?A grow tent fits about one or two trained plants in 60 x 60 cm (2 x 2 ft), two in 2 x 4 ft and two to four in 4 x 4 ft: roughly 1–4 plants per square metre.Numbers · Grower practice
- How much electricity does a home grow use?A home grow uses about 300 kWh per photoperiod run in a 2 x 2 ft tent (150 W LED plus fans) and about 850 kWh in a 4 x 4 ft tent (500 W LED plus fans), with 4 weeks of veg at 18/6 and 10 weeks of flower at 12/12.Numbers · Established
- How much weed does one plant produce?One indoor cannabis plant produces whatever its share of the canopy yields: roughly 100–500 g of dry flower per square metre of canopy in controlled trials, depending mostly on light.Numbers · Grower practice
- How much yield should I expect per watt or per square foot?Expect roughly 100–500 g of dry flower per square metre (about 10–50 g, or 0.3–1.6 oz, per square foot) indoors, rising with light; well-run research rooms at 750–900 µmol/m²/s measured 500–750 g/m².Numbers · Supported
- How should I feed autoflowers?Feed autoflowers lighter than photoperiods but don't starve them: plain water or about EC 0.4–0.6 mS/cm for the first two weeks, 0.8–1.2 in weeks 3–4 and 1.2–1.8 in flower, starting at a quarter to half the label rate.How-to · Grower practice
- How tall do cannabis plants get indoors?Indoor cannabis usually finishes about 60–150 cm (2–5 ft) tall, because the grower sets the height: a photoperiod plant grows 50–100% taller after the flip, stretchy cultivars up to 3×, so a plant flipped at 40–60 cm endNumbers · Grower practice
- What are pistils?Pistils are the female reproductive organs of cannabis flowers.Definition · Established
- What are terpenes in cannabis?Terpenes are the volatile aroma compounds cannabis makes in its glandular trichomes, alongside cannabinoids; myrcene, limonene, caryophyllene, pinene and terpinolene are common.Definition · Established
- What is a node on a cannabis plant?A node on a cannabis plant is the point on a stem where a leaf and its axillary bud attach; branches, flowers, preflowers and clone roots all start there.Definition · Established
- What is THCA?THCA (tetrahydrocannabinolic acid) is the acid form of THC that the living cannabis plant actually makes and stores in its trichome heads.Definition · Established
- What is the difference between a strain and a cultivar?A cultivar is a formal botanical term: a cultivated plant group that is distinct, uniform and stable when propagated, by seed or cuttings.Definition · Established
- What is the difference between fan leaves and sugar leaves?Fan leaves are the big palmate leaves, usually 5–9 serrated leaflets on long stalks, that do most of a cannabis plant's photosynthesis and carry few trichomes.Definition · Established
- What is the difference between hemp and marijuana?Hemp and marijuana are the same species, Cannabis sativa.Definition · Established
- What is the difference between THC and CBD plants?THC and CBD plants are the same species; the difference is which enzyme turns the shared precursor CBGA into cannabinoid acids.Definition · Established
- What pot size is best for autoflowers?For autoflowers, an 11–15 L (3–4 gal) pot is the usual final pot, and up to 19 L (5 gal) is forgiving for a first grow.How-to · Grower practice
- When do autoflowers start flowering?Autoflowers usually start flowering about 3–5 weeks after sprouting, with white pistils at the main tip around day 21–35, whatever the light schedule.Numbers · Grower practice
- When do cannabis plants show their sex?Cannabis plants usually show their sex about 4–6 weeks from seed under long days, when single preflowers form at the nodes; research found the first pair around the 7th node.Numbers · Supported
- When should I flip my plants to flower?Flip a photoperiod plant to 12/12 (or 13/11) when it is about half the final height your space allows, because most plants grow 50–100% taller, sometimes up to 3×, in the first two to three weeks after the flip.How-to · Supported
- Why do photoperiod plants need long nights to flower?Photoperiod cannabis is a short-day plant: it measures the uninterrupted night with phytochrome, a light-sensing pigment, and flowers once the night passes a cultivar-specific critical length, around 10–11 hours of darknDefinition · Established
- Why is my autoflower so small?An autoflower ends up small when something slows it in the first 3–5 weeks, before it starts flowering by age.Troubleshooting · Grower practice
Germination11
- Can I plant seeds straight into the final pot?Yes. You can plant cannabis seeds straight into the final pot, and for autoflowers it's the GenetixBay house position: sow into an 11–15 L final pot, because any setback costs an auto time.How-to · Grower practice
- Do cannabis seedlings need a humidity dome?Cannabis seedlings don't strictly need a humidity dome, but one helps in dry rooms for the first 3–7 days by holding 65–75% RH around them.How-to · Grower practice
- Do cannabis seeds need light to germinate?No. Cannabis seeds do not need light to germinate; they need warmth (22–27 °C / 72–81 °F), moisture and air, and germinate well in the dark.How-to · Supported
- Do seeds that float mean they are duds?No. A cannabis seed that floats is not necessarily a dud; the float test is unreliable because it mostly measures air trapped in or on the shell, and many floaters sink within a few hours and germinate normally.Myth check · Myth
- How long is the seedling stage?The cannabis seedling stage lasts about 2–3 weeks from emergence.Numbers · Grower practice
- What do I do if the seed shell is stuck on my seedling?A seed shell stuck on a cannabis seedling (helmet head) usually comes off by itself within a day or two.Troubleshooting · Grower practice
- What light schedule should seedlings get?Photoperiod and autoflower seedlings both do well on 18/6: 18 hours of light at about 150–300 µmol/m²/s, a DLI of 10–19 mol/m²/day.Numbers · Grower practice
- Which way up do I plant a germinated seed?Plant a germinated cannabis seed taproot (radicle) pointing down, 0.5–1.5 cm (¼–½ in) deep, in moist, light mix.How-to · Grower practice
- Why are my seedling's leaves yellow or pale?Yellow or pale cannabis seedling leaves usually mean overwatering, too little light, or hunger in an inert medium.Troubleshooting · Supported
- Why is my seedling drooping?A drooping cannabis seedling is most often overwatered: a big pot or soggy plug leaves its tiny roots short of oxygen.Troubleshooting · Supported
- Why won't my seeds germinate?Cannabis seeds usually fail to germinate because they are too cold, too wet, too dry or old.Troubleshooting · Supported
Environment23
- Are purple (blurple) LEDs as good as white LEDs?Purple (blurple) LEDs grow cannabis about as well as white LEDs at the same PPFD, because photon quantity and efficacy matter far more than colour.Comparison · Supported
- Can I grow cannabis with household LED or CFL bulbs?You can keep seedlings and clones alive under household LED or CFL bulbs, but you can't grow good flower with them.How-to · Supported
- Can I open my tent during the dark period?You can open a flowering tent during the dark period only if the room outside is dark too, and briefly.How-to · Supported
- Do I need an intake fan or is passive intake enough?Passive intake is enough for most grow tents: an exhaust fan pulls air out and low, open intake ports let fresh air in, keeping the tent under slight negative pressure so smell can't escape.How-to · Grower practice
- How can I measure PPFD without a PAR meter?Without a PAR meter, estimate PPFD from the fixture's published PPFD map at your hanging height, cross-check with watts × µmol/J ÷ canopy area, and use a phone or lux meter only for comparisons.How-to · Supported
- How cold is too cold for cannabis?Cannabis gets too cold when air at the canopy stays below about 15 °C (59 °F): growth, water use and ripening slow sharply, and humid cold nights invite bud rot.Troubleshooting · Supported
- How do I check if my hygrometer is accurate?Check a hygrometer with a salt test: seal it for 12–24 hours in a bag or jar with a damp slurry of table salt, which holds air at about 75 % RH at room temperature.How-to · Established
- How do I keep my grow tent warm in winter?Keep a grow tent warm in winter by keeping the light's own heat in: slow the exhaust on a thermostat, insulate the tent and floor, run the lights during the coldest hours, and only then add a thermostat-controlled heater.How-to · Grower practice
- How do I lower the humidity in my grow tent?Lower grow-tent humidity by removing the water the plants transpire: more exhaust if the room air is drier, then a dehumidifier sized to roughly the litres you irrigate per day, running through lights-off.How-to · Supported
- How do I lower the temperature in my grow tent?Lower grow-tent temperature by removing the light's heat faster: more exhaust from a cooler room, drivers or ballasts outside the tent, lights dimmed 10–20 %, and lights run in the coolest hours.How-to · Supported
- How do I raise the humidity in my grow tent?Raise grow-tent humidity by keeping the water your plants transpire: slow the exhaust first, then add a humidifier on a humidistat.How-to · Grower practice
- How do I stop my grow tent from smelling?Stop a grow tent smelling by keeping it under negative pressure and sending all exhaust air through an activated-carbon filter rated at or above the fan's airflow.How-to · Grower practice
- How long does a carbon filter last?A grow-tent carbon filter usually lasts about 12–18 months of continuous use, less in humid rooms or with very pungent cultivars, longer if it only runs in flower.Numbers · Grower practice
- How long does the flowering stage take?Most photoperiod cannabis flowers for about 7–10 weeks, counted from the first pistil clusters, but harvest comes about 9–12 weeks after the flip, because the flip isn't day 1 of flower: a 10–14 day transition comes firsNumbers · Supported
- In which weeks of flower do buds grow the most?Cannabis buds put on most of their mass from roughly week 3 to week 7 of flower, counted from the first pistil clusters, and keep gaining weight and resin right through the final weeks.Numbers · Supported
- LED or HPS: which is better for cannabis?LED versus HPS for cannabis quality and yield per photon is an open question at GenetixBay: perhaps.Comparison · Contested
- Should I mist my plants?Don't mist established cannabis plants, and never mist buds in flower.How-to · Grower practice
- Should I run my room warmer with LEDs than with HPS?Yes, run an LED room about 1–3 °C (2–5 °F) warmer than an HPS room.Numbers · Supported
- Should my exhaust fan run 24/7?Yes, in most vented tents the exhaust fan should run 24/7, slowed by a temperature and humidity controller rather than switched off.How-to · Grower practice
- What happens if my lights accidentally stay on during flower?One accidental 24-hour light period in flower usually costs a photoperiod plant a day or two, not the crop.Troubleshooting · Grower practice
- What should I look for when buying a grow light?When buying a grow light, look first for efficacy above about 2.5 µmol/J, a measured PPFD map over your tent's footprint showing 600–900 µmol/m²/s average with edges at least 70–80 % of the centre, and a real wattage at How-to · Supported
- What wattage LED do I need for my tent?For flower, plan on roughly 25–40 W of efficient LED (2.5–3.0 µmol/J) per square foot, about 270–430 W/m², which gives an average of about 600–900 µmol/m²/s.Numbers · Supported
- Why don't lumens matter for grow lights?Lumens don't matter for grow lights because lumens, lux and foot-candles measure light as the human eye sees it, weighted heavily to green-yellow, while plants use photons from 400–700 nm about equally.Definition · Established
Nutrients17
- Can I use regular garden fertiliser on cannabis?Yes, regular garden fertiliser works on cannabis in soil, because roots take up the same ions whatever the label says.How-to · Supported
- Do banana peels, coffee grounds or eggshells feed cannabis?No, not in any useful way: feeding cannabis with kitchen scraps is a Myth.Myth check · Myth
- Do mycorrhizae help cannabis?Mycorrhizae can help cannabis a little, mainly with phosphorus uptake in low-phosphorus soil, but commercial inoculants often don't deliver.How-to · Contested
- Does compost tea work for cannabis?Compost tea is not a meaningful fertiliser for cannabis, and its disease-control effects are inconsistent.How-to · Contested
- Does foliar feeding work on cannabis?Foliar feeding works on cannabis as a quick, small top-up, not as a feed.How-to · Supported
- How do I fix nutrient lockout?Fix nutrient lockout by finding its cause first: most lockout is root-zone pH out of range, salt build-up or damaged roots, not true antagonism.Troubleshooting · Supported
- How long can mixed nutrient solution be stored?Mixed mineral nutrient solution keeps about a week if it is covered, dark and cool, roughly the same 7-14 days a DWC reservoir runs between changes; an open, warm, lit jug is best used within 1-3 days.How-to · Grower practice
- In what order should I mix nutrients?Mix nutrients into the full volume of water in this order: silica first, then Cal-Mag or part A, then part B, then any additives, stirring between each, and adjust pH last.How-to · Established
- Is it worth fixing a deficiency in late flower?It depends what you're seeing.Troubleshooting · Grower practice
- Should I feed every time I water?Whether to feed every watering depends on the medium.How-to · Grower practice
- Should I use full-strength nutrients from the feeding chart?Usually not at first.How-to · Supported
- What are macronutrients and micronutrients?Macronutrients are the elements cannabis needs in large amounts: nitrogen, phosphorus and potassium (primary) plus calcium, magnesium and sulfur (secondary), fed at roughly 30-250 mg/L each.Definition · Established
- What does N-P-K mean on a fertiliser label?N-P-K on a fertiliser label is the guaranteed percentage by weight of nitrogen (N), phosphate (P2O5) and potash (K2O).Definition · Established
- When does pre-fertilised soil run out of nutrients?A typical pre-fertilised bagged potting mix feeds cannabis for about 2-4 weeks, then runs short, usually in mid-veg.Troubleshooting · Grower practice
- When should I stop feeding before harvest?Don't stop feeding before harvest.How-to · Myth
- Which nutrients do I actually need for a first grow?For a first grow you need one complete base nutrient made for your medium (soil, or a two-part A and B for coco and hydro), Cal-Mag only if you use RO or soft water or coco, a pH down, and a pH and EC meter.How-to · Supported
- Will damaged leaves recover after I fix the problem?Mostly no. Brown, burnt or dead leaf tissue never recovers, and badly yellowed leaves rarely regreen; only mildly pale leaves may partly recover once the nutrient is back.Troubleshooting · Grower practice
pH and EC8
- Are pH test drops accurate enough?pH test drops and strips are accurate enough for soil and rough water checks, but not for hydro or coco.Comparison · Grower practice
- Can I use distilled water or rainwater for cannabis?Yes. Distilled, RO and clean rainwater work well for cannabis because they start near EC 0 with no sodium, chloride or alkalinity, but they also carry no calcium or magnesium and no pH buffer.How-to · Supported
- Can I use vinegar or lemon juice to lower pH?You can, but you shouldn't: the idea that vinegar or lemon juice is a fine pH down is a Myth.Myth check · Myth
- Do I really need to pH my water?In coco, rockwool and hydro, yes: adjust every batch to about pH 5.5-6.2 in hydro or 5.8-6.3 in coco, because these media barely buffer pH.How-to · Established
- How do I fix soil pH that is too high or too low?Raise soil pH with agricultural or dolomitic lime and lower it with elemental sulfur; both take weeks, so build them into the mix before planting.How-to · Established
- How do I raise or lower the pH of my water?Lower pH with a mineral acid pH down (phosphoric, nitric or sulfuric) and raise it with potassium hydroxide or potassium silicate, after the nutrients are in.How-to · Established
- Is a TDS meter the same as an EC meter?Yes, essentially. A TDS or ppm meter measures electrical conductivity (EC) and multiplies it by an assumed factor: 0.5 on the 500 scale, 0.7 on the 700 scale, sometimes 0.64.Comparison · Established
- Should I pH my water before or after adding nutrients?Adjust pH after adding nutrients.How-to · Established
Systems12
- Are fabric pots better than plastic pots?Fabric pots are better than plastic pots for hand-watered soil, mainly because they dry faster and run cooler.Comparison · Supported
- Can I mix soil and coco?Yes, you can mix soil and coco: adding buffered coco to potting mix lightens it, holds water well and stays airy.How-to · Grower practice
- Can I reuse soil from my last grow?Yes, you can reuse soil from your last grow if the plants were healthy.How-to · Grower practice
- How much water does a cannabis plant use per day?A cannabis plant uses roughly 50–250 mL of water a day as a seedling, 0.5–1.5 L in veg and about 1.5–2 L a day as a large flowering plant indoors.Numbers · Grower practice
- How often should I water my cannabis plants?Water by weight, not by calendar.How-to · Grower practice
- Should I put gravel or rocks in the bottom of my pots?No, you don't need gravel or rocks in the bottom of a pot, and the idea that a drainage layer is necessary to stop waterlogging is a myth.Myth check · Myth
- Should I top off my reservoir with plain water or nutrient solution?Let the reservoir's EC decide what you top off a hydro reservoir with.How-to · Grower practice
- Should I water when the lights come on or before they go off?Water cannabis soon after the lights come on, ideally within the first 1–3 hours.How-to · Grower practice
- What coco to perlite ratio should I use?The usual coco to perlite ratio is 70:30 for hand-watered pots.Numbers · Grower practice
- What is super soil?Super soil is a heavily amended organic soil, rich in compost, worm castings and slow-release amendments, cooked moist for weeks and meant to feed a cannabis plant through most of its life with plain water.Definition · Grower practice
- What soil should I use for growing cannabis?The best soil for growing cannabis indoors is a quality bagged potting mix, peat- or coco-based with compost and a light starter fertiliser, opened up with 20–35% perlite or pumice.How-to · Supported
- Why does water run straight through or pool on top of my pot?Water runs straight through a pot when the mix has dried out, shrunk from the wall and turned water-repellent, so water channels down the sides and out the bottom while the root ball stays dry.Troubleshooting · Grower practice
Training8
- Can I defoliate autoflowers?You can defoliate autoflowers, but only lightly, and GenetixBay advises tucking instead.How-to · Grower practice
- How can I increase my yield indoors?Increase indoor yield with more usable light first: dry flower yield rose linearly from 116 to 519 g/m² as canopy PPFD went from 120 to 1,800 µmol/m²/s.How-to · Supported
- How do I get bigger, denser buds?Bigger, denser buds come mainly from more light at every bud site: 800–1,200 µmol/m²/s at canopy in flower at ambient CO₂, on an even canopy.How-to · Supported
- How long does a plant take to recover after topping?A healthy cannabis plant takes about 3–7 days after topping before the two new shoots show visible regrowth, and roughly a week until they grow at equal speed.Numbers · Grower practice
- My plant is too tall for my tent: what can I do?If your plant is too tall for the tent, bend it rather than cut it.Troubleshooting · Grower practice
- What is schwazzing?Schwazzing is an aggressive defoliation schedule that strips almost every fan leaf at the start of flower and again around day 21.Definition · Contested
- When should I stop training my plants?Stop training cannabis by technique.How-to · Grower practice
- Why are my buds airy or larfy?Airy, larfy buds are usually buds that got too little light: lower and inner sites often receive a fraction of the canopy-top PPFD, well below the 800–1,200 µmol/m²/s flower target.Troubleshooting · Supported
Pests7
- Can I use neem oil in flower?No: neem oil does not belong on cannabis in flower.Myth check · Myth
- Do sticky traps work?Sticky traps work as a monitoring tool, not a cure.How-to · Established
- How did pests get into my sealed tent?Pests don't appear from nowhere in a sealed cannabis tent; something carried them in.Troubleshooting · Supported
- How do I prevent pests in an indoor grow?To prevent pests in an indoor grow, stop them coming in and catch the rest early.How-to · Supported
- What are the small white bugs in my soil?Small white bugs in cannabis soil that jump when disturbed are almost always springtails: about 1.5 mm (1/16 in), harmless scavengers of wet, organic media.Troubleshooting · Established
- What can I safely spray on plants in flower?On cannabis in flower, the safe default is to spray nothing on buds.How-to · Supported
- What is eating holes in my leaves?Holes in cannabis leaves are usually chewing pests, and the clue left behind names them.Troubleshooting · Established
Diseases5
- Do milk or baking soda sprays work for powdery mildew?Milk and bicarbonate sprays suppress powdery mildew on leaves; they do not cure it.Myth check · Myth
- How do I stop algae in my reservoir or on my medium?Algae in a cannabis reservoir or on the medium means light is reaching wet, nutrient-rich surfaces.Troubleshooting · Established
- My buds got mouldy in the jar: what now?Mouldy buds in a curing jar must be thrown away, not trimmed and smoked.Troubleshooting · Established
- Should I wash my buds after harvest?Wash buds only if they are dirty, such as outdoor plants covered in dust, ash, pollen or insects.How-to · Grower practice
- What is the white fuzz on top of my soil?White fuzz on top of cannabis soil is usually harmless fungal growth (mycelium) feeding on organic matter in a surface that stays wet.Troubleshooting · Grower practice
Diagnosis9
- Are praying leaves a good sign?Praying leaves, with fan leaves angled upwards and the blades flat, usually mean a cannabis plant is well watered and getting good light.Troubleshooting · Grower practice
- Can you smoke buds from a hermaphrodite plant?Yes, buds from a hermaphrodite plant can be used if they are free of mould.Troubleshooting · Supported
- How do I stop my plants from turning hermaphrodite?Prevent hermaphrodites by starting with well-bred genetics first, then removing the stresses that reveal weak plants.How-to · Supported
- Is it normal for leaves to droop at night?Yes, cannabis leaves commonly droop or lower during the dark period and lift again within an hour or two of lights-on.Troubleshooting · Grower practice
- Why are my pistils turning brown early?Pistils that brown early, before about week 6 of flower, have usually been pollinated, heat- or light-stressed near the lamp, handled, or are the cultivar's normal colour.Troubleshooting · Grower practice
- Why are my stems weak and floppy?Weak, floppy cannabis stems usually come from too little light, which makes plants stretch, and too little air movement, because stems thicken in response to being moved.Troubleshooting · Supported
- Why are there seeds in my buds?Seeds in cannabis buds mean the flowers were pollinated, usually weeks before harvest.Troubleshooting · Supported
- Why is my plant growing single-finger leaves?Single-finger, rounded leaves on a cannabis plant usually mean it is revegging: switching from flowering back to vegetative growth because its nights became too short or were broken by light.Troubleshooting · Supported
- Why is my whole plant pale or light green?A cannabis plant that is pale all over is usually short of nitrogen, or has roots that can't take nitrogen up because they are overwatered, cold or at the wrong pH.Troubleshooting · Supported
Harvest and cure13
- Can I dry my buds in my grow tent?Yes, a grow tent makes a good drying space once the plants are out and the light is off.How-to · Grower practice
- Can I quick-dry buds in an oven, microwave or paper bag?Quick-drying cannabis in an oven or microwave makes harsh, grassy flower and drives off the volatile terpenes a slow dry keeps; the idea that it is a harmless shortcut is a Myth.Myth check · Myth
- How do I check trichomes?Check cannabis trichomes with a 60–100× loupe or clip-on phone microscope, looking at the heads on the calyxes, not the sugar leaves.How-to · Grower practice
- How do I rehydrate over-dried buds?To rehydrate over-dried buds, seal them in a jar with a fresh, slightly moister bud for about a day, then check that the equilibrated jar reads 55–62% RH (water activity 0.55–0.62).How-to · Grower practice
- How do I trim buds?Trim cannabis by removing the big fan leaves at harvest, then snipping or brushing the sugar leaves back to the bud, either wet on harvest day or dry once small stems snap after 7–14 days.How-to · Grower practice
- How full should I fill my curing jars?Fill curing jars about three-quarters full, loosely, so the buds don't crush and air can move around them when you burp.Numbers · Grower practice
- How soon after harvest can I smoke my buds?Cannabis can be smoked once it is properly dried, usually 7–14 days after harvest, when small stems snap and a sealed sample jar reads a stable 58–65% RH.Numbers · Grower practice
- Should I hang the whole plant or cut branches to dry?Hang the whole plant if your dry room runs on the dry side or you want the slowest dry, because the stem and leaves slow water loss.How-to · Grower practice
- Should I harvest the whole plant at once or in stages?Harvest a cannabis plant in stages when the top colas are ready and the lower buds clearly aren't, often a difference of several days.How-to · Grower practice
- What happens if I harvest too early or too late?Harvest too early and you lose weight and resin: buds are still filling, and cannabinoid concentration hasn't reached its plateau.Troubleshooting · Supported
- Why did my buds lose their smell?Buds lose their smell mostly because volatile terpenes escaped during a fast, warm or over-dry dry, and then during storage in warmth, light or air.Troubleshooting · Supported
- Why do my curing jars smell like ammonia?An ammonia or musty smell in a curing jar means the buds went in too wet and microbes are starting to break them down, a step before visible mould.Troubleshooting · Grower practice
- Why is my homegrown weed harsh?Homegrown cannabis is usually harsh because it was dried too fast, over-dried, or smoked before a proper cure, not because it wasn't flushed.Troubleshooting · Supported
Breeding1
Equipment4
- How do I set up a grow tent?Set up a grow tent in this order: check the circuit, build the frame, hang the carbon filter high with the exhaust fan pulling through it, open low intakes on the far side, hang the light level over the canopy, add a cliHow-to · Grower practice
- Is an indoor grow a fire risk?An indoor grow is a real fire risk only when it's set up badly: overloaded circuits, daisy-chained power strips, damaged cords, heaters and water near plugs.How-to · Established
- What meters do I actually need for growing?For a first grow you need three meters: a pH meter calibrated with pH 7 and pH 4 buffers, an EC meter checked against a 1.413 mS/cm standard, and a thermo-hygrometer with min/max memory, salt-tested for accuracy.How-to · Established
- What size grow tent should I get?For a first grow, a 60 × 60 cm (2 × 2 ft) to 90 × 90 cm (3 × 3 ft) tent, 160–180 cm (5.3–6 ft) tall, is the forgiving choice: one to three plants and a 100–320 W LED.Numbers · Grower practice
Cloning and mother plants12
- Can I root clones in plain water?Yes. Cannabis cuttings can root in plain water, usually in 10–21 days, but results are less even than in a plug or aeroponic cloner.How-to · Grower practice
- Can I take clones from a flowering plant?Yes. You can clone a flowering cannabis plant (monster cropping), but expect slower rooting, often 2–4 weeks, and a further 2–6 weeks of odd, single-bladed regrowth while the cutting re-vegs under 18–24 hours of light.How-to · Grower practice
- Do clones need nutrients before they root?No. Unrooted cannabis clones don't need nutrients: they live on reserves in their stem and leaves, and plain water or a very weak solution (EC up to about 0.4 mS/cm, 200 ppm500) is enough.How-to · Grower practice
- Do I need rooting hormone for clones?You don't strictly need rooting hormone for cannabis clones, but it clearly helps.How-to · Supported
- How do I clone a cannabis plant?To clone cannabis, cut an 8–15 cm (3–6 in) shoot tip with 2–3 nodes from a healthy vegetative plant, cut below a node with a clean blade, dip it in IBA rooting gel and set it in a moist plug.How-to · Supported
- How do I reveg a plant after harvest?To reveg a photoperiod cannabis plant after harvest, leave the lower branches with some leaves and small buds, put it back on 18/6 or 24/0, feed lightly and wait.How-to · Grower practice
- How long do clones take to root?Most cannabis clones root in 7–14 days, with the first roots showing around days 7–12 at a medium temperature of 22–26 °C (72–79 °F), high humidity and gentle light.Numbers · Supported
- Is a clone the same sex and age as its mother?A cannabis clone is genetically the same as its mother, including her sex: every clone of a female is female.Definition · Established
- What humidity and light do clones need?Unrooted cannabis clones do best at 75–90% RH (a leaf VPD of about 0.2–0.5 kPa), a medium temperature of 22–26 °C (72–79 °F), and gentle light of 50–150 µmol/m²/s on 18–24 hours, a DLI of about 3–10 mol/m²/day.Numbers · Grower practice
- What is the best medium for rooting clones?There's no single best medium for rooting cannabis clones; the best is the one that stays moist while holding plenty of air.Comparison · Supported
- When are rooted clones ready to transplant?Rooted cannabis clones are ready to transplant when several white roots, about 2–5 cm (1–2 in) long, are poking out of the sides or base of the plug, usually 10–14 days after cutting.Numbers · Grower practice
- Why are my clones wilting?Cannabis clones wilt because they have no roots to replace the water their leaves lose.Troubleshooting · Grower practice
Outdoor growing8
- Can I grow autoflowers outdoors?Yes: autoflowers grow well outdoors because they flower by age, not day length, finishing about 9–14 weeks from seed.How-to · Grower practice
- Can I start plants indoors and move them outside?Yes: starting photoperiod cannabis indoors 3–6 weeks before your last frost and moving it outside is standard practice, if you harden it off over 7–14 days.How-to · Grower practice
- How do I grow outdoors in a short northern season?To grow outdoors in a short northern season (roughly 50° latitude and above, with frost by late September or October), pick plants that finish by late September: autoflowers, or early-finishing photoperiod lines.How-to · Grower practice
- How much sun does outdoor cannabis need?Outdoor cannabis needs at least 6–8 hours of direct sun a day, and more is better: full summer sun reaches 1,500–2,000 µmol/m²/s at midday and a daily light integral of roughly 40–60 mol/m²/day on clear days.Numbers · Supported
- How should I prepare soil or pots for outdoor plants?For outdoor cannabis in the ground, dig a hole about 60–90 cm (2–3 ft) wide and 45–60 cm (18–24 in) deep, mix in compost and perlite or pumice, and aim for soil pH 6.0–7.0 with good drainage.How-to · Grower practice
- When do outdoor plants start flowering?Outdoor photoperiod cannabis starts flowering when days shorten past its cultivar's threshold, often around 14–14.5 hours of daylight.Numbers · Supported
- When is outdoor cannabis ready to harvest?Outdoor cannabis is ready when its trichomes are mostly cloudy with some amber (roughly 5–20%), which at 35–50° latitude usually falls between mid-September and late October in the Northern Hemisphere and between March aNumbers · Grower practice
- When should I plant cannabis outdoors?Plant cannabis outdoors after your last frost, once nights stay above about 10 °C (50 °F).Numbers · Grower practice
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