Minecraft wiki entry for Pumpkin_and_melon_farming, associated text: 1 Growth mechanics
1.1 Finding Seeds
1.2 Growth Factors
2 Manual farms
2.1 Simple farms
2.2 Large farms
2.3 Multi-level farms
2.4 Rapid-harvest farms
3 Semi automatic farms
3.1 Basic design
3.2 Stackable design
3.2.1 Base Layer
3.2.2 Piston and Farm Layers
3.2.3 Cap and Water Layers
4 Fully automatic farms
5 The Most Effective Pumpkin/Melon farm
5.1 Opaque block detection farms
5.1.1 Single plant detection
5.1.2 Dropper hopper trigger
5.1.3 Dual-piston growth detection
5.2 BUD circuit farm
5.2.1 Design 6 (doesn’t work in bedrock edition)
5.3 Vertical observer farms
5.3.1 Design 7
5.3.2 Design 8
5.4 Horizontal observer farm
5.4.1 Design 9
5.4.2 Design 10 - stackable horizontal piston observer melon/pumpkin farm
5.5 Time-based farm
5.5.1 Design 11 - High-density pumpkin and melon farm