A few growers place charcoal in the bottom of containers to absorb excess salts and maintain sweet soil, if plants are grown more than a few months.
The growers discovered this in 1835
( z1 discover :ARG0 ( z2 person :ARG0-of ( z3 grow ) ) :ARG1 ( z4 this ) :time ( z5 date-entity :year 1835 ) )