(FORTUNE Small Business) – "Find a need and fill it" was the advice young Horace Hagedorn received from Martin Small, the man said to have invented roll-on deodorant, who insisted that those six words were a ticket to becoming a millionaire. With the help of a scientist who transformed fertilizer into water-soluble blue crystals, Hagedorn founded Miracle-Gro in 1950. The former adman offered a $100,000 prize for a world-record tomato grown with his product, used a fatherly pitchman for television ads, and crammed newspapers with gushing testimonials. Miracle-Gro became a staple for competitive suburbanites fulfilling their hunger for horticultural one-upmanship, and it reaped gargantuan fruit for Hagedorn: a $350 million business that today captures 85% of the home fertilizer market. The father of fertilizer died Jan. 31 at the age of 89. --HANNAH CLARK