Ripley's upscale housewife heroine, recovering from injuries inflicted by a crazed Defense Department nominee (Mulch, 1994), returns for a second outing. This time, amateur detective and better-than-amateur organic gardener Louise Eldridge lifts up a family from low ebb--her husband the spy is facing a career crisis, her daughters are grappling with sex and social-consciousness issues--when she lands a PBS gardening-show gig. Predictably enough, the station itself is a compost heap of lust, jealousy, and sponsor pressures. Before Louise can get her soil turned and her reputation seeded, her predecessor, a discontented socialite who's been kicked upstairs to a geriatrics show, is poisoned by pesticide--a murder that occurs after an unlikely ladies' room catfight involving Louise herself. So Louise is a prime suspect, and her family and suburban D.C. neighbors, charmed by her ways with color-changing tulips, set out to save her good name--and her life--from a killer now targeting her. Ripley's domestic and professional scenes pull all the approved material from today's self-help shelves, and she's hampered by peremptory characterization, absent-minded prose (a ``sharp gulf between them''), and a leading lady who's soap- operatic in her suffering. On the up side, the gardening nonfiction--ten small and distinct chapters--is informative and fun.