From 1 to 4 P.M. on Saturday and next Sunday, staff horticulturists will conduct tours and give demonstrations on spring lawn care.

At White Flower Farm in Litchfield, Conn., where Landon Winchester, a staff horticulturist, fields gardeners' questions, digging in the dark is not unheard of.

The I.P.M. program at the National Arboretum has been coordinated by Scott Aker, staff horticulturist.

After lunch at the inn, guided tours of the display gardens at White Flower Farm will be given by staff horticulturists.

Susan Moody, staff horticulturist, steeps herself in the customs of those times to create authentic plant and floral displays for the Romanesque chapels and cloisters.

Maintenance of the Central Garden will be the responsibility of Nancy Tim, the staff horticulturist.

Last year, from April to late fall, Eileen Weinsteiger, one of Rodale's staff horticulturists, grew more than 100 pounds of salad in 50 square feet.

Don Evans, the staff horticulturist, who has cared for these trees for 20 years, led the way over toppled 50-foot palms and ripped-up cycads, trying to hold back tears.

Carolyn Lydon, a staff horticulturist, said the best results demanded ripping out smaller trees and girdling large ones - cutting through bark to halt a tree's growth and hasten its end.

Ned J. Garvey, a staff horticulturist at the Beltsville Plant Exchange office, puts it this way.