| Cuban Sugar Cookies | Beyond Top Shelf | | 70/30 | View variety |
| Cucamonga | Top Dawg Seeds | | 50/50 | View variety |
| Cujo Cookies | Cabin Fever Seed Breeders | | 70/30 | View variety |
| Culo | Wyeast Farms | | 60/40 | View variety |
| Cultazepam | Cult Classics Seeds | | 70/30 | View variety |
| Cum Laude | positronics | | 30/70 | View variety |
| Cuntz | MassMedicalStrains | | 50/50 | View variety |
| Cup Cakez | The Bakery Genetics | | 60/40 | View variety |
| Cupcake | Farmhouse Genetics | Unknown Strain · [unknown Birthday Cake] × Blue Kush · [probably probably] | 50/50 | View variety |
| Cura | AlpinStash | R4 · (probably) × Unknown Strain | 50/50 | View variety |
| Cura Verde | Mephisto Genetics | | 50/50 | View variety |
| Curaga | AlpinStash | | 50/50 | View variety |
| Currency | Offensive Selections | | 60/40 | View variety |
| Currylato | The Plug Seedbank | | 50/50 | View variety |
| Curse of Momo | Terp Fi3nd | | 50/50 | View variety |
| Curvature | Red Scare Seed Company | | 60/40 | View variety |
| Curve Breaker | Twenty 20 Genetics | | 50/50 | View variety |
| Custard Cream | Cream of the Crop Seeds | Exact parent cross unknown · Known background: Afghani · Nepal · [probably Probably] · Hawaii · [probably Probably] | 80/20 | View variety |
| Customer Service | In House Genetics | | 60/40 | View variety |
| Cutie Pie | Motarebel | | 40/60 | View variety |