Hi billbowls, If your trees are new it's highly likely that they have been given feed in the nursery, otherwise feed them with a compound fertilizer every february at the makers recomended rate.
Also give them an organic mulch (this can be done now) around the roots to conserve moisture and keep weeds down.
To prevent a failed crop keep them well watered during dry periods especially between july to september, while the fruit is growing. Good Luck Tbird+