Reading a Yield Figure on a Seed Page
Yield is quoted in at least three incompatible units. Grams per square metre describes an indoor canopy under a stated wattage, grams per plant describes an outdoor or greenhouse specimen, and ounces appear on American listings at 28.35 grams each. A 550 g/m² claim and a 550 g/plant claim are not comparable, and no calculation reconciles them without knowing area and plant count.
Wet and dry weight differ by roughly 75 to 80%. Fresh flower weighing 1,000 grams straight off the plant settles at 200 to 250 grams once it has been dried and cured. Reputable catalogues quote dry weight, and any figure sitting four times above comparable strains almost certainly describes wet material.
Every published figure hides assumptions: a full-spectrum LED drawing 400 to 600 watts per square metre, a canopy that fills the footprint, healthy roots and a grower who does not make timing mistakes. These are optimum-condition numbers. A first cycle typically lands 30 to 50% below the quoted range, and that gap closes with experience rather than with a different strain.
Weight per cycle and weight per year answer different questions. A photoperiod line producing 600 g/m² across a sixteen-week cycle returns roughly 1,950 grams a year on one square metre, while an autoflower at 400 g/m² over eleven weeks returns about 1,890. When space rather than time is the constraint, cycle length matters nearly as much as the headline figure.
- Identify the unit first. Grams per square metre, grams per plant and ounces are not interchangeable. Confusing the first two is the most common reason a first harvest feels like a failure when it is actually normal.
- Confirm dry or wet weight. If the catalogue never states it, assume dry but plan for the lower end of the range, since drying removes around three quarters of the harvested mass.
- Check the growing environment. Indoor, greenhouse and full-season outdoor figures for the same genetics can differ threefold, so a number without context tells you very little.
- Look for the lighting assumption. Modern listings usually imply 400 to 600 watts of LED per square metre with the canopy filled edge to edge.
- Factor in plant count and pot size. Reaching 600 g/m² from nine small plants and from one heavily trained plant demands completely different schedules and container volumes.
- Apply an experience discount. Landing 30 to 50% under the quoted range on a first or second run is expected and is not a fault of the seed.
Why Dry Weight and Wet Weight Never Match
Fresh cannabis flower is around 75 to 80% water by weight, and removing that water is the entire purpose of drying. A kilogram of wet trimmed bud finishes somewhere between 200 and 250 grams. The only meaningful moment to weigh a harvest is after the cure, not on harvest day.
Drying conditions change both the number and the quality. Seven to twelve days at roughly 18°C and 60% relative humidity preserves terpenes, while three days under a fan at 25°C removes moisture faster and strips volatiles with it. Taking flower below about 10% moisture costs weight that cannot be recovered.
Decide in advance what you are counting. Trim, larf and sugar leaves headed for extraction should be weighed separately from jarred flower, otherwise your total will never line up with catalogue figures, which describe cured buds alone.
The Genetic Traits Behind a Heavy Harvest
Genetics set the ceiling and nothing in the grow room raises it. The most direct trait is calyx stacking: flowers piling tightly along a branch weigh far more than the same volume of airy bud. Density carries a cost, because tight cores hold moisture and are the first place botrytis appears during a humid late flower.
Internode spacing decides how many bud sites fit into the height available. Gaps of two to four centimetres put more flowering points under the same fixture, while lanky lines waste vertical space on bare stem. Flower-to-leaf ratio matters too: lines with little foliage inside the bud trim faster and lose less weight at the trimming table.
Stretch is the multiplier growers underestimate most often. Indica-leaning lines add roughly 50 to 100% of their height after the flip, balanced hybrids 100 to 200%, and sativa-dominant lines up to 300%. Flipping a strain that triples in height inside a 1.2 metre tent guarantees light burn across the top colas.
Flowering length correlates directly with weight. A twelve-week line gets three more weeks of bulking than a nine-week line and usually shows it on the scale, but it also occupies the space longer and, outdoors, risks finishing in October rain. Pick the length that fits your calendar rather than the biggest number in the catalogue.
| Genetic trait | How it shows in the plant | Effect on harvest weight | What to look for in the description |
|---|
| Calyx stacking | Tight, heavy flowers along each branch | Direct increase, the single largest genetic factor | Notes on density plus a mould-resistance rating |
| Internode spacing | 2-4 cm between nodes on compact lines | More bud sites per unit of canopy height | Wording such as compact or short-noded |
| Flower-to-leaf ratio | Few sugar leaves inside the bud | Higher usable yield and faster trimming | Mentions of easy trim or low leaf content |
| Stretch factor | 50-300% height gain after the flip | Determines how well tent volume is used | A stated stretch multiplier or final height |
| Lateral branching | Strong side shoots reaching the canopy | Enables SCROG and multi-cola training | Descriptions of bushy or vigorous growth |
| Flowering length | 8-14 weeks depending on the line | Longer bulking phase adds mass | An exact week range rather than about 9 weeks |
Yield Patterns of Indica, Sativa and Hybrid Lines
Indica-dominant plants stay compact, stack dense flowers and finish in eight to nine weeks. Weight per plant is moderate, yet weight per square metre can be excellent, because nine of them fit under a single fixture in a sea-of-green arrangement.
Sativa-dominant lines produce the largest individual plants and the longest cycles, ten to fourteen weeks indoors and often into late October outdoors. Given height and a long season they out-produce everything else, and in a small tent they underperform badly.
Most current yield leaders are polyhybrids borrowing density from indica parents and vigour from sativa ones. They typically double in height, finish in nine to ten weeks and tolerate training well, which is why breeders keep returning to that formula.
Realistic Harvest Expectations Indoors, Outdoors and Under Glass
Indoors you buy predictability, outdoors you get scale for free. An indoor cycle is bounded by canopy area and light intensity and repeats reliably four times a year. An outdoor plant is bounded by season length, weather and, in most jurisdictions, a legal plant count that makes maximising each individual plant worthwhile.
Indoor output tracks light and area more closely than anything else. Grams per watt is the traditional shorthand, with 1.0 g/W considered a good result, but the industry has moved to PPFD and DLI because efficiency varies between fixtures. Filling the canopy from edge to edge matters as much as the wattage printed on the box.
Outdoors, the vegetative window sets the final size. A seedling planted in April builds a two to three metre frame by August, while one planted in June rarely passes a metre. Root volume drives that growth, so 50 litres of container or open ground with good drainage does more for final weight than any bottled additive.
A greenhouse sits between the two. It extends the season by six to eight weeks at both ends, keeps autumn rain off dense colas and, with blackout screens, allows a second flowering cycle inside one summer. Its weak point is ventilation, because without strong extraction humidity climbs and mould arrives before the harvest does.
| Setup | Typical plant count | Realistic dry yield range | Main limiting factor |
|---|
| 60x60 cm tent, photoperiod | 1 plant | 80-150 g per cycle | Canopy area and total light output |
| 100x100 cm tent | 4 plants | 300-500 g per cycle | Even light coverage in the corners |
| 120x120 cm tent with SCROG | 4-6 plants | 450-700 g per cycle | Screen management and available height |
| 80x80 cm tent, autoflowers | 4 plants | 150-300 g per cycle | Fixed cycle, no extended vegetative phase |
| Mid-size greenhouse | 3-6 plants | 500-1,500 g per plant | Ventilation and humidity control |
| Full outdoor season | 1-3 plants | 500 g to 2 kg per plant | Season length and autumn weather |
Photoperiod or Autoflower for Maximum Output
The flowering mechanism is the whole difference. A photoperiod plant flowers when you shorten the light cycle, so you decide how large it grows first, whether that means three weeks of vegetative growth or ten. An autoflower begins flowering on an internal clock around day 21 to 28 whatever you do, which places a hard cap on its final size.
Per plant, photoperiods win comfortably. Per year on the same square metre the gap narrows sharply: four or five autoflower cycles at 350 to 450 g/m² can match three photoperiod runs at 550 to 650 g/m². The shorter exposure also spreads risk, since losing an eleven-week run costs far less than losing a sixteen-week one.
Modern autoflowers are not the weak plants of a decade ago, and several lines pass 500 g/m² under strong lighting. Their real limitation is recovery time. With no extended vegetative phase to absorb a transplant shock or a lockout, they should be sown straight into their final 11 to 18 litre pot and run on an 18/6 or 20/4 schedule throughout.
Fast-flowering versions occupy the middle ground. They keep photoperiod control over the vegetative stage while cutting one to two weeks from flowering, which suits greenhouses, short northern seasons and indoor growers running a tight rotation. Expect a modest weight penalty against the original photoperiod version of the same line.
- Control over vegetative length. Photoperiods let you veg for three weeks or ten and size the plant to the space, which is the single biggest lever on weight per plant.
- Total cycle time. Autoflowers run 70 to 90 days from seed to harvest, while photoperiods typically need 14 to 18 weeks including vegetative growth.
- Harvests per year. One square metre supports four to five autoflower cycles or three photoperiod cycles, which changes the annual arithmetic considerably.
- Lighting schedule and electricity. Autoflowers run 18 to 20 hours of light throughout, so they use more power per day but for fewer weeks in total.
- Ceiling per plant. A trained photoperiod can exceed 250 grams indoors, while a strong autoflower in an 18 litre pot usually tops out near 100 to 150 grams.
- Tolerance of mistakes. Photoperiods can be given an extra fortnight of vegetative growth to recover, whereas an autoflower simply flowers on schedule regardless.
Fast-Version Lines as a Middle Ground
Fast versions come from crossing a photoperiod line with an autoflowering parent and then selecting offspring that still respond to the light cycle. The result flowers in seven to eight weeks rather than nine or ten while remaining fully controllable.
The trade is a few per cent of weight in exchange for two or three weeks of calendar. Outdoors that can mean harvesting in mid-September ahead of the rain, and indoors it can mean five cycles a year instead of four.
Environment and Feeding: Converting Potential Into Weight
Light is the first limiting factor and the one most often set too low. Aim for roughly 400 to 600 µmol/m²/s during vegetative growth and 800 to 1,000 in flower, which puts the daily light integral near 40 mol/m²/day. Doubling wattage without matching temperature, humidity and CO₂ produces stress rather than extra grams.
Climate decides how fast the plant can use that light. A vapour pressure deficit of 0.8 to 1.2 kPa in vegetative growth and 1.2 to 1.5 in flower keeps transpiration moving, which in practice means 24 to 26°C at 60 to 70% humidity early and 20 to 24°C at 45 to 50% late. Air movement through the canopy removes the humid pockets where rot begins.
Root volume caps plant size directly. Indoors, 10 to 15 litres per plant suits a nine-week photoperiod run and 18 to 25 litres supports larger trained plants. Coco and hydroponic systems grow faster than soil because oxygen reaches the roots more easily, though they also punish irrigation errors within hours instead of days.
Feeding should climb in steps rather than jump. An EC of 0.8 to 1.2 for seedlings, 1.4 to 1.8 in vegetative growth and 1.8 to 2.4 in mid-flower works for most lines, with pH held at 5.8 to 6.2 in coco and 6.2 to 6.5 in soil. Clawed, very dark leaves indicate excess nitrogen, not a hungry plant.
| Input factor | Recommended range | Impact on final weight | Common mistake |
|---|
| Light intensity (PPFD) | 400-600 in veg, 800-1,000 in flower | The primary driver of bulking | Weak fixture or one hung far too close |
| Root volume | 10-15 l standard, 18-25 l for trained plants | Sets the ceiling on plant size | Undersized pots for a long vegetative phase |
| Vegetative time | 3-8 weeks depending on tent height | Determines the number of bud sites | Flipping before the canopy is filled |
| Temperature and VPD | 24-26°C early, 20-24°C late, 0.8-1.5 kPa | Controls growth rate and rot risk | Managing temperature but ignoring humidity |
| Nutrient EC | 0.8-1.2 seedling, 1.4-1.8 veg, 1.8-2.4 flower | Supports bulking when raised gradually | Overfeeding at the start of flowering |
| CO₂ enrichment | 800-1,200 ppm in a sealed room only | Adds weight when light is already high | Dosing in a vented tent with weak lighting |
Light Intensity and Canopy Coverage
Modern LED fixtures reach useful flowering intensity at roughly 400 to 600 watts per square metre. Coverage matters as much as the headline number, because a fixture concentrating output in the centre leaves the corners producing larf while the middle of the canopy bleaches.
A flat canopy uses the whole footprint. Keeping every top within 10 to 15 centimetres of the same plane stops light falling on bare stems, and that is the practical reason trained plants outweigh untrained ones grown in identical conditions.
Light penetrates about 30 to 40 centimetres into a dense canopy. Growth below that line turns into airy popcorn, so clearing it during the stretch redirects resources upward instead of sacrificing productive leaf area.
Training and Canopy Work for Heavier Harvests
Training exists to defeat apical dominance. Left alone, a plant channels most of its energy into one central cola and produces a handful of large flowers surrounded by small ones. Spreading that growth into an even canopy converts the same light into eight or ten competing tops, and that redistribution is where the additional weight comes from.
Topping and FIM remove or damage the growing tip, usually above the fourth or fifth node, turning one main stem into two or four. Plants need five to seven days to resume normal growth, so the technique belongs in vegetative growth and never in the second half of an autoflower's short life.
SCROG and SOG are systems rather than single cuts. A screen set 20 to 25 centimetres above the pots, with shoots tucked under it for two to three weeks, fills a square metre using two to four plants. Sea of green does the reverse: nine to sixteen small plants, one or two weeks of vegetative growth each, and a fast rotation.
Leaf work is the easiest thing to overdo. Removing fan leaves that shade bud sites at the flip and again around day 21 of flower improves penetration, while stripping more than a third of the canopy at once stalls growth for a week. Lollipopping the lower 25 to 30% concentrates resources in flowers that will actually finish.
- Topping and FIM. Cutting above the fourth or fifth node converts one dominant stem into two or four main colas. Allow five to seven days of recovery before flipping the lights.
- Low stress training. Tying branches down horizontally spreads the canopy without wounding the plant, which makes it the safest option for autoflowers on a fixed schedule.
- SCROG. A screen 20 to 25 cm above the pots fills a square metre from two to four plants, at the cost of two or three extra weeks of vegetative growth.
- SOG. Nine to sixteen small plants with a week or two of vegetative time each deliver a fast rotation, which suits growers without legal plant-count limits.
- Defoliation. Selective removal of shading fan leaves at the flip and around day 21 improves light penetration, but taking more than a third at once costs a week of growth.
- Lollipopping. Clearing the lower 25 to 30% of the plant before flowering redirects energy from popcorn buds into the tops that receive full intensity.
Mistakes That Quietly Cost You Grams
Flipping at the wrong moment is the most expensive error. Too early and the canopy never fills the footprint; too late and a line that triples in height reaches the fixture by the third week of flowering.
Feeding and watering errors come next. Running EC above 2.4 in early flower, letting pH drift outside 5.8 to 6.5, or alternating drought with flooding all cost growth that cannot be recovered later in the cycle.
The final week decides more than growers expect. Harvesting while trichomes are still clear sacrifices both weight and potency, and a fast, hot dry removes moisture, terpenes and grams at the same time.
Compare More Cannabis Seed Types
Harvest weight is only one of the criteria worth applying to a seed pack. Competition results describe the same genetics through a different lens, focusing on aroma, resin and judged quality rather than grams, and reading both categories together gives a fuller picture of what a line will do in your space.
