| Critical+ 2.0 | Dinafem | | 60/40 | View variety |
| Critical+ 2.0 Autoflowering | Dinafem | | 60/40 | View variety |
| Critical+ Automatic | Dinafem | | 60/40 | View variety |
| Critically Early Guerrilla | HighRise Seeds | | 70/30 | View variety |
| Critters | Organic Gardeners | | 70/30 | View variety |
| Critters Cookies | Greenlife Seeds US | | 70/30 | View variety |
| Critterz | Greenpoint Seeds | | 60/40 | View variety |
| Crockett's AutoDog | Crockett Family Farms | | 50/50 | View variety |
| Crockett's Tangie | Crockett Family Farms | | 40/60 | View variety |
| Crocketts Confidential | Crockett Family Farms | | 60/40 | View variety |
| Crocketts Dawg | Crockett Family Farms | | 40/60 | View variety |
| Crocketts Haze | Crockett Family Farms | | 10/90 | View variety |
| Crocketts Sour Tangie | Crockett Family Farms | | 40/60 | View variety |
| Croissant | Lit Farms | | 70/30 | View variety |
| Cromo | Shuga Seeds | | 60/40 | View variety |
| Cronuts | Alphakronik Genes | | 70/30 | View variety |
| Crop Circle | Cream of the Crop Seeds | | 50/50 | View variety |
| Crop Doctor | Cream of the Crop Seeds | | 80/20 | View variety |
| Cropical Fruit | Cream of the Crop Seeds | | 50/50 | View variety |
| Cropolope | Cream of the Crop Seeds | | 40/60 | View variety |