Informative nonfiction for summer reading; Rustic essays that don't wilt; In Praise of Practical Fertilizer, by John Baskin. New York: W.W. Norton & Co. 217 pp. $14.95.

To me, the best prose is organic, not industrial -- it seems to be grown from seed rather than hammered into shape on a typewriter. From this point of view, John Baskin has harvested a bumper crop.

Fittingly, Baskin writes from a small farm in Ohio. His essays are short, simple, and rustic without turning ''folksy,'' full of the sights and sounds of rural Chester Township. In the words of the author, they are ''ordinary things with the suggestion of the extraordinary: gestures, nuances, conversations, anecdotes, aphorisms, asides, grievances, grudges, soliloquies, over-the-fence ramblings and, in moments of weakness, a rant or two.''

A conversation: Miss Mary explains to the Squire why lima beans are not to be trusted. An aphorism: ''Machinery has the interesting capability of magnifiying a man's strengths or his weaknesses.'' An anecdote: how Mr. Leaning's father stumbled on a strain of corn that won a prize in Paris. A grievance: ''The modern house is Nomadic in concept, and we are the modern Bedouins, reading the want ads for split-level oases, proper benefits, and a built-in dog.''

In an earlier book, Baskin described how the Corps of Engineers flooded nearby New Burlington, turning a living community into a recreational lake. In this one there is nothing so dramatic, but much that is nourishing.