Minecraft wiki entry for Crop_farming, associated text: For the fastest growth per seed, a full layer of hydrated farmland with crops in rows is ideal. Under these conditions, the probability of growth during each update is 1⁄3, or approximately 33%. Most (4⁄5) planted crops reach maturity within 31 minutes (about 1.5 minecraft days). In fact, 31 minutes is very close to the ideal time at which to harvest if an auto-farming system is set to a timer, precisely 31 minutes and 3.14 seconds. For all plants to have this probability, crop rows must be separated by empty farmland or by a different crop, and the edges and corners of the field must be empty farmland. However, this probability also applies to crops adjacent to one or two non-farmland blocks (e.g. blocks of water in the middle of a field for hydration and/or a torch) due to the floor function.