Coljam by Underground Seeds
Bred by Underground Seeds from Colombian Gold × Jamaican Lambsbread, Coljam is a sativa-leaning cannabis variety. Indoors it typically finishes flowering in around 105 days after the flip to 12/12. The environment targets below are the same stage-by-stage bands the Cultivar journal grades real Coljam grows against.
🌿 Start a Coljam journal — free →
Similar strains
| Breeder | Underground Seeds |
|---|---|
| Type | sativa |
| Flowering time | ±105 days |
| Environment | Indoors |
| Lineage | Colombian Gold × Jamaican Lambsbread |
| Descendants | Cobra |
🌱 Get Coljam seeds →
Affiliate link — supports Cultivar at no cost to you.
🧬 Explore the family: Colombian Gold · Jamaican Lambsbread · Cobra
Ancestry Pedigree
Unknown or Legendary
Original Strains
Original Strains
Unknown or Legendary
Original Strains
Growing Coljam: what to expect
As a sativa-leaning plant, plan for a big stretch after the flip (often 100–200%) — flip earlier than feels natural and keep training options ready. Sativa-leaning plants also generally prefer a lighter feed than heavy indicas. Growers familiar with Colombian Gold or Jamaican Lambsbread will recognize much of its behavior. Whatever the listing says, the cut in YOUR tent is the ground truth: log feedings, readings, and photos, and let the trends — not the label — drive decisions.
Coljam FAQ
How long does Coljam take to flower?
Coljam typically flowers in around 105 days after switching to a 12/12 light schedule. Individual phenotypes vary, so judge harvest readiness by trichome color, not the calendar.
Is Coljam an indica or a sativa?
Coljam is listed as sativa.
What are the parents of Coljam?
Coljam was bred from Colombian Gold × Jamaican Lambsbread by Underground Seeds.
What environment does Coljam like?
Standard cannabis bands work well: VPD 0.8–1.1 kPa in veg and 1.0–1.4 kPa in flower, with humidity stepping down from 65–75% as a seedling to 40–50% in late flower. See the stage-by-stage table on this page.
📷 Growing Coljam and something looks off? Free AI photo diagnosis →
Facts compiled from public breeder listings. Growing Coljam? A structured journal — with your feedings, readings, and photos — is how you find what THIS cut actually wants.
Track your own grow free — the journal grades your environment against these bands →
Get the one-page grow reference card
VPD, pH by medium, deficiency symptoms and dry/cure targets on a single printable page. Free — plus the occasional grow-data breakdown. No spam, unsubscribe in one click.