Question: What product do you recommend to break through the hardpan below the sandy soil? I am going to plant a grapevine in this spot. Richard Answer: I recommend you use PENETRATE-Liquid Biotiller, MAXIMIZE-Microbes & Minerals, OPTIMIZE-Soil Optimizer and NOURISH-Biosol. If that layer is hard compacted clay or anything like that, these products will work great. If it is genuine, real hardpan, which is the same as concrete or rock, then the products will not have a beneficial effect. The only way to change real hardpan is to drill through it.