whomever owned my property before me must have used tons of fertilizers without regard to what the soil already had. When I recently renovated my lawn the extension office's recommendation was to not any any phosphorous or potassium for the next TWO YEARS before it was *that high*. There is no "magic number" fertilizer. Only suppliment what is deficient.

Most compost contains all the magneasium you'll need although some plants like tomatoes and peppers seem to like it a little higher than others. The molasses, I suspect was done as a homemade remedy to increase bacterial and fungal microbes to congregate in the area which would increase the soil food web within the garden. Again, if the land has been fertile there is likely no reason to add this type of amendment - and if the land was sterile it wouldn't do much good either.

Still, little harm in it all - with the exception of over fertilizing nutrients that aren't needed.

Adding any synthetic fertilizer to soil will not help the soil in anyway, and whether it might do harm depends on the condition of the soil. Nutrient imbalances will create more problems than what is thrown down will help, too much of something can keep the plants from uptaking other, needed, nutrients and, especially with synthetic fertilizers that not used by the plants more than likely will flow out of your soil with the water into the ground water adding to the pollution of the water you drink. More and more places today are banning the some types of fertilizer use unless there is a good, reliable soil test that shows the need because of this water pollution from excess nutrients.