CONTENTS

CONTENTS

Cannabis anatomy

Cannabis is an intricate and versatile plant, with each part playing a vital role in its growth, reproduction, and chemical production. Understanding its anatomy is essential for mastering cultivation and maximising yield potential. Below is a detailed breakdown of the plant’s components, their functions, and how they contribute to overall health and productivity.

The anatomy of a Cannabis plant

Roots

Description The root system anchors the plant in the growing medium, absorbing water and nutrients essential for growth.
Function
  • Uptake of water and nutrients.
  • Interaction with beneficial microbes in soil or hydroponic systems.
Tip Healthy roots are white or light tan and odourless. Ensure proper drainage and aeration to avoid root rot.

Stem

Description The main structural support connecting roots to leaves and flowers.
Function
  • Transports water, nutrients, and sugars between roots and foliage.
  • Provides structural integrity for supporting buds and leaves.
Tip Training methods like low-stress training (LST) or topping encourage lateral growth, improving light penetration.

Branches

Description Offshoots from the main stem that support leaves and flowers.
Function
  • Facilitate photosynthesis through leaves.
  • Provide sites for bud formation.
Tip Prune lower branches during late vegetation to focus energy on more productive upper bud sites.

Leaves

TYPES
  1. Fan leaves: Large leaves that collect light for photosynthesis.
  2. Sugar leaves: Smaller leaves near buds, often covered in trichomes.
Function
  • Photosynthesis: converts light into energy.
  • Respiratory exchange through stomata.
Tip While fan leaves are essential during vegetation, selective removal during flowering can improve light distribution and airflow.

Flowers (Buds)

Description Reproductive structures containing the highest concentration of cannabinoids and terpenes.
Function
  • Female flowers produce resin with THC, CBD, and other cannabinoids.
  • richome-covered, storing cannabinoids and terpenes.
Tip Monitor buds for signs of overwatering, nutrient deficiencies, or pests during development.

Trichomes

Description Tiny, crystal-like structures on flowers and sugar leaves.
Function
  • Protect the plant from pests and UV radiation.
  • Produce and store cannabinoids, terpenes, and flavonoids.
Tip Harvest when trichomes shift from clear to cloudy or amber, depending on the desired cannabinoid profile.

Calyxes

Description Small, tear-shaped structures at the flower base, housing reproductive organs.
Function
  • Protect seeds during development.
  • Primary resin-producing sites in unfertilised plants.
Tip A high calyx-to-leaf ratio indicates superior strain quality.

Pistils and Stigmas

Description Hair-like structures emerging from the calyx, with stigmas changing colour as the plant matures.
Function
  • Capture pollen for fertilisation.
  • Indicate maturity based on stigma colour.
Tip For sinsemilla (non-seeded buds), remove male plants to prevent fertilisation.

Fan leaves vs. Sugar leaves: key differences

Feature Fan Leaves Sugar Leaves
Location Throughout the plant Near buds
Size Large Small
Role Photosynthesis Support bud development
Cannabinoids None Low, with some trichomes coverage
Practical Use Compost or pruning waste Harvested for concentrates or edibles

Key considerations for Cultivators

  1. Recognising plant health
    Watch for yellowing leaves, discoloured stems, or underdeveloped roots as signs of stress.
  2. Maximising cannabinoid production
    Maintain optimal light, temperature, and nutrient levels to enhance trichome production.
  3. Customising for strain characteristics
    Understand variations in plant anatomy across strains, e.g., broader leaves in indica vs narrow leaves in sativa.

Frequently asked questions

A recap with plenty of useful information

THC is produced in the trichomes, the crystal-like structures on flowers and sugar leaves.

Healthy roots are white or light tan, firm, and odourless.

Fan leaves are large and broad, essential for photosynthesis, while sugar leaves are smaller and trichome-covered, near the buds.

Yellowing leaves often indicate nutrient deficiencies, overwatering, or improper pH levels.

Check trichomes on buds. They should turn from clear to cloudy or amber, depending on your desired effects.

Pistils capture pollen during fertilization and indicate maturity by changing colour as the plant ages.

Selective removal improves light penetration and airflow but avoid over-pruning.

The stem provides structural support and transports water, nutrients, and sugars throughout the plant.

Ensure proper drainage, avoid overwatering, and maintain good aeration around the roots.

Calyxes protect developing seeds and serve as primary resin-producing sites in unfertilised plants.

Yellowing leaves, purple stems, or drooping branches can indicate stress from nutrients, water, or light.

Optimise light intensity, temperature, and humidity during flowering, and ensure adequate phosphorus and potassium levels.

It refers to more calyxes relative to leaves, indicating better-quality buds that are easier to trim.

Pistil colour is an indicator but not definitive. Always check trichomes for accurate harvest timing.

Use precise feeding schedules, maintain ideal environmental conditions, and cure buds properly post-harvest.

Low-stress training encourages lateral growth and improves light distribution without damaging the plant.

Transplant into a larger pot with fresh growing medium to allow roots to expand.

Yes, sugar leaves have lower concentrations than buds but can be used for making concentrates or edibles.

Trichomes act as a natural sunscreen, protecting flowers and sugar leaves from UV damage.

Indicas have broader leaves and shorter structures, while sativas have narrow leaves and taller, lankier growth.