my suggestion is when a plant is farmed, automatically clone and replant the same plant.

here is a piece of code i was testing to do just that
After farming the plant change to gying state,  This change it back to a previous state and update the genes like its a new plant

        void OnGrowableGathered(GrowableEntity plant, Item item, BasePlayer player)
        {
            NextTick(() =>
            {
                if (plant.State == PlantProperties.State.Ripe) || (plant.State == PlantProperties.State.Mature)
                {
                    plant.State = PlantProperties.State.Seedling;
                    plant.stageAge = 0f;
                    plant.Age = 0;
                    for (int i = 0; i < 6; i++)
                    {
                        plant.Genes.Genes[i].Set(plant.Genes.Genes[i].Type, true);
                    }
                }
                else
                {
                    plant.State = PlantProperties.State.Dying;
                    plant.stageAge = 0f;                    
                }
                plant.SendNetworkUpdate();
            });

            return;
        }

That is a bit too automated for me and I prefer this plugin exactly how it is in its current form.

Thanks for the suggestion, however I feel that this is a little out of scope of this plugin and could even be a plugin of its own. For now I would like to keep the functionality close to or related to the lifespan of the plants.