Grower Glossary – LUpdated 9 days ago
L
The Grower Glossary – L focuses on light, leaves, and living systems — essential for healthy photosynthesis and canopy management. Understand how leaf health and lighting spectrum impact every stage of growth.
Lactic Acid Bacteria (LAB)
Beneficial microbes that ferment organic matter, improving nutrient uptake and plant immunity.
Grower Slang: “LABs,” “ferment microbes.”
Cronk Tip: Found naturally in living soil and compost teas — enhances root health and organic nutrient cycling.
Ladybug
A beneficial predator insect that feeds on aphids, mites, and other soft-bodied pests.
Grower Slang: “Guardian bug.”
Cronk Tip: Use as part of your IPM (Integrated Pest Management) program for natural pest control.
Lahar (Soil Term)
Volcanic ash-based soil known for high mineral content and aeration.
Grower Slang: “Volcano mix.”
Excellent natural base for mineral-rich media.
Lamp Distance
The space between your light source and canopy top.
Grower Slang: “Light height.”
Cronk Tip: Maintain:
Seedlings: 24–30 in.
Veg: 18–24 in.
Bloom: 12–18 in. (depending on PPFD & fixture).
Lamp Life
The number of hours a bulb or LED is rated to operate efficiently.
Grower Slang: “Light lifespan.”
Replace HPS/MH bulbs every 9–12 months; LEDs last up to 50,000 hours.
Larf
Small, underdeveloped buds that grow on lower branches with low light exposure.
Grower Slang: “Popcorn buds,” “fluff.”
Cronk Tip: Remove lower growth early in flower to focus energy on top colas.
Lateral Branch
A side branch that grows horizontally from the main stem.
Grower Slang: “Side shoot,” “arm.”
Training laterals helps shape canopy and increase yield potential.
Latent Heat
The heat energy released or absorbed during evaporation or condensation.
Grower Slang: “Air moisture heat.”
Understanding latent heat helps manage humidity and temperature balance.
Leaf Blade
The broad, flat part of the leaf where photosynthesis occurs.
Grower Slang: “Fan leaf.”
Healthy blades = healthy energy production.
Leaf Curl
The rolling or cupping of leaves caused by heat stress, overfeeding, or low humidity.
Grower Slang: “Tacoing,” “canoeing.”
Cronk Tip: Keep VPD balanced and reduce EC slightly if curl persists.
Leaf Margin
The edge of a leaf. Serrated or smooth margins help identify species or diagnose stress.
Grower Slang: “Leaf edge.”
Leaf Spot
Discolored patches caused by nutrient imbalance, pests, or pathogens.
Grower Slang: “Leaf blotch.”
Identify the cause — fungal spots differ from deficiency signs.
Leaf Tip Burn
Brown or crispy tips on leaves from nutrient excess.
Grower Slang: “Burned tips.”
Cronk Tip: Indicates feeding too “hot.” Reduce EC by 0.2–0.4 and flush medium.
Leaflet
Each individual section of a compound leaf — cannabis leaves usually have 5–9 leaflets.
Grower Slang: “Finger,” “blade.”
Leaf Surface Temperature (LSTemp)
The actual temperature of leaf surfaces, often 1–3°C cooler than air temperature.
Grower Slang: “Leaf temp.”
Infrared thermometers help fine-tune lighting and VPD accuracy.
LED (Light Emitting Diode)
Modern, energy-efficient grow lighting with customizable spectrum.
Grower Slang: “LED rig,” “diodes.”
Cronk Tip: Full-spectrum LEDs boost growth efficiency and terpene retention.
Leachate
Runoff water that drains from pots after watering.
Grower Slang: “Runoff.”
Testing leachate pH/EC helps diagnose nutrient buildup or lockout.
Leaf Miner
A pest that tunnels between leaf layers, leaving visible trails.
Grower Slang: “Tunnel worm.”
Control with neem oil or predatory insects like parasitic wasps.
Leggy Seedling
A seedling that stretches tall and thin due to insufficient light.
Grower Slang: “Stretched baby.”
Fix by lowering light intensity or transplanting deeper.
Lenticel
Small pores on stems that allow gas exchange.
Grower Slang: “Stem pores.”
Visible lenticels can help diagnose stem health in cuttings or clones.
Light Bleaching
When intense light destroys chlorophyll, turning top leaves or buds pale white.
Grower Slang: “Light burn,” “bleach.”
Cronk Tip: Lower PPFD or raise lights — ideal canopy PPFD = 900–1200 during bloom.
Light Burn
Leaf or bud damage caused by lights too close to the canopy.
Grower Slang: “Scorched tops.”
Symptoms: Yellowing or white tips near light source.
Light Cycle
The ratio of light to darkness within a 24-hour period.
Grower Slang: “Schedule,” “photoperiod.”
Veg: 18/6 or 20/4
Bloom: 12/12
Autos flower regardless of cycle.
Light Deprivation (Light Dep)
A technique that forces outdoor plants to flower early by covering them to simulate shorter days.
Grower Slang: “Light dep,” “pulling tarps.”
Used to harvest multiple outdoor crops per season.
Light Leak
Unwanted light during the dark period that can confuse flowering plants.
Grower Slang: “Glow leak.”
Can cause hermaphrodites — always seal tents and rooms fully.
Light Meter
A device measuring intensity (lux or PPFD) from grow lights.
Grower Slang: “PAR meter.”
Essential for maintaining consistent lighting conditions.
Light Pollution
External or stray light affecting outdoor grow cycles or night conditions.
Grower Slang: “Street glow.”
Can prevent flowering in photoperiod plants.
Light Spectrum
The range of wavelengths emitted by a light source, measured in nanometers (nm).
Grower Slang: “Color band,” “light mix.”
Cronk Tip: Blue (450nm) = Veg | Red (660nm) = Bloom | UV/IR = Terpene Boost.
Light Stress
Overexposure to intense light causing slowed growth or bleaching.
Grower Slang: “Too bright.”
Monitor leaf temperature and reduce PPFD if symptoms appear.
Light Timer
A device that automates on/off cycles for grow lights.
Grower Slang: “Timer box.”
Cronk Tip: Always use a heavy-duty timer for LED or HID fixtures.
Lift Test
Grower method for checking soil moisture by lifting pots.
Grower Slang: “Pot weight test.”
If the pot feels light — it’s time to water. Reliable for avoiding overwatering.
Lime (Dolomitic Lime)
A soil amendment containing calcium and magnesium carbonate.
Grower Slang: “Soil buffer.”
Cronk Tip: Raises pH in acidic soil and provides long-term nutrient stability.
Living Soil
An active, microbe-rich soil ecosystem that feeds plants naturally.
Grower Slang: “No-till,” “living mix.”
Cronk Tip: Feed the soil — not just the plant. Use PuurOrganics for microbial life and balanced nutrition.
Localized Feeding
Applying nutrients directly near root zones or specific areas instead of saturating the entire medium.
Grower Slang: “Spot feed.”
Useful for correcting deficiencies in large containers or beds.
Lockout (Nutrient Lockout)
When improper pH or salt buildup prevents plants from absorbing nutrients.
Grower Slang: “Locked,” “nutrient wall.”
Cronk Tip: Flush medium with pH-balanced water and reset with a mild feed.
Loam
A balanced soil type containing sand, silt, and clay.
Grower Slang: “Perfect mix.”
Ideal structure for both drainage and moisture retention.
Lobed Leaf
A leaf shape with multiple rounded sections — common in mature cannabis.
Grower Slang: “Fan leaf.”
Can change under light or genetic influence.
Low Stress Training (LST)
A gentle training technique that bends stems and ties them down to shape plant structure.
Grower Slang: “Bend and tie,” “soft train.”
Cronk Tip: Start LST early in veg for even canopy growth and maximum light exposure.
Lumens
A measurement of total visible light emitted by a source.
Grower Slang: “Brightness.”
Not as precise as PPFD for plant use, but still useful for general lighting comparison.
Lux
A measure of light intensity at a given surface area (lumens per square meter).
Grower Slang: “Light meter reading.”
Used for estimating PPFD when a PAR meter isn’t available.
Lysis (Cell Lysis)
The breakdown or bursting of plant cells, often caused by freezing or stress.
Grower Slang: “Cell rupture.”
Relevant in cold stress or improper freezing during hash making.
Lytic Enzymes
Enzymes that break down organic residues and dead root material.
Grower Slang: “Root cleaners.”
Cronk Tip: Promotes clean root zones and better nutrient absorption.
Light Bar
An LED fixture design with multiple linear diodes for even light distribution.
Grower Slang: “LED bar,” “strip light.”
Preferred in modern tents and commercial grows for uniform canopy coverage.