I've talked about in the past about how cover crops (AKA green manure) can build biomass, build biology, suppress weeds, make nutrients more available to plants and a lot of other beneficial things. One thing I haven't talked about here is some of the potential negatives, but there is an easy fix. The downside to cover crops is that it can also, in some cases, harbor soil borne diseases and help keep them going. Things like fusarium can use the cover crop and help perpetuate the disease. The fix to get the benefits, without the negatives, according to some studies that were done in recent years, is simply not to plant after tilling in the cover crop for 2 to 3 weeks. As the host plant dies and starts to decompose, the disease dies off with it and it is safe to plant your pumpkin plant.