Students at John S. Martinez School, a public elementary school in New Haven, are eating greener and healthier. Along with 30 other schools in the state of Connecticut, the school began to participate Monday in the U.S. Department of Agriculture’s Fresh Fruit and Vegetable Program, which promotes balanced nutrition by introducing fresh fruits and vegetables into the school lunchroom. The Fruit and Vegetable Program — established in 2002 — is a plan to provide selected schools across the nation with fresh foods in order to increase healthy consumption among America’s youth. The program is funded by $6 million in federal grants.