Two games I play use this system for agriculture : If an action is required, it will pause the growing progress. In SotA, this would result in plants only going to the next stage once the watering is done for the current stage, so if a plant needs 24 hours to grow, it needs 1 watering withing the first 8 hours. To grow to the next stage, it would need to be watered withing those 8 hours or else the growing process would freeze until you water it. Then, when it grows into its next stage, that's when you can do its watering, if it gets watered within 8 hours, it will grow immediately to the next stage else it will freeze. If a plant is left frozen in a state for as long as its growing stage (so for a 24 hour plant, if it remains unwatered for 16 hours (8x2)) then it will wither and yield no result. Could this be an idea?