Soil Sampler is my favorite tool. I never leave home without it. After replanting a field 7-8 times, I noticed the soil minerals going down. If in big quantities some minerals are lowering the "happiness" of certain plants. Seems like plants like every mineral to be in a range rather than more than needed. Some plants complain about overcrowding in an empty surrounding. Others are happy even surrounded. I suspect overcrowding means something else. Probably mineral saturation instead. Some plants may seem fully grown but if are still maturing, have a chance to fail at harvesting. I.E. a tomato plant at 85% maturity seems big enough but when harvested may fail to provide fruit. 100% grown tomato always gives off fruit. Noticed some plants are more sensible to sub-optimal heat and more tolerable to sub-optimal coldness or vice versa. I rely more on the heatmap. Heatmap functionality helps a lot. YieldPotential heatmaps are hidden after the list of PopulationHeatmaps. In the map menu, click the dropdown, after the first list of plants there is the same list but for YieldPotential. All this have been changed in the past and since the game is still in progress, are subject to change.