Todd wrote:

What I don't understand is how the plant would have enough
power left in it to grow both potatoes and tomatoes. Must
be the richest soil the plant could handle without burning
the plant!

When kindergartners are taught to plant beans with just blotting paper
and water even five year olds quickly learn that once germinatiom
occurs (in darkness) plants receive most of their growth energy from
sunlight. Plants will thrive and fruit in the poorest soil given
sufficient water and sunlight. Left to their own devices plants set
only enough fruit to reproduce. Using fertilzers and other agri
techniques is only to increase yield in less time... actually
selective hand harvesting will increase yield better than fertilizing.
Commercial growers fertilize because that costs less than constant
labor. As a home grower I don't use any feretilizers but all else
equal (water and sunlight) I selectively harvest constantly and end up
with a larger/better crop than had I just fertilized... easy to prove
by planting several tomato plants and fertilizing half and selectively
harvesting the other half while adding no fertilizer... constant
selective harvesting ensures a large less seedy crop... I'd much
rather an abundance of smaller veggies than a few giant seedy
specimens Most home gardeners over fertilize and over water, they do
more harm than good. More and more produce is being produced
hydroponically with no soil.