Cannabis is a flowering plant, and like every flowering plant, it inherits its traits the same way Gregor Mendel's peas did. You don't need a biology degree to use this — you just need three ideas.

The three ideas

  • Every trait is controlled by a pair of genes — one from mom, one from dad.
  • Some versions of a gene are dominant. The dominant one wins when both are present.
  • When you cross two pure-breeding parents, the first generation (F1) looks the same. When you cross two F1 plants together, the F2 generation splits.
F1 vs F2 in practice
F1 (first cross)
  • Plants look uniform — strong hybrid vigor
  • Phenos are tight and predictable
  • Best for the consistent commercial bag
F2 (sibling cross)
  • Plants vary wildly across the tray
  • Recessive traits show up — color, terpene, structure
  • Best for phenotype hunters looking for rare keepers

Why this matters for collectors

When a breeder says "F1" they're promising uniformity. When they say "F2," they're inviting you to hunt. Both are valid, but they're not interchangeable — and the price you pay should reflect which one you're getting.

Is F1 always better than F2?+
No. F1 is more predictable; F2 is more diverse. Hunters love F2. Commercial growers love F1.
What about F3, F4, F5?+
Each successive sibling cross stabilizes traits further. By F5–F6, a well-selected line is usually called an IBL (inbred line).