Though it has been possible in the past to learn to predict DNA hydration patterns from crystallographic data, there is ambiguity in the choice of training data (both in terms of the relevant set of cases and the features needed to represent them), which limits the usefulness of standard learning techniques. Thus, we have developed a knowledge-based system to generate machine learning experiments for inducing DNA hydration pattern classifiers. The system takes as input (1) a set of classified training examples described by a large set of attributes and (2) information about a set of learning experiments that have already been run. It outputs a new learning experiment, namely a (not necessarily proper) subset of the input examples represented by a new set of features. Domain specific and domain independent knowledge is used to suggest subsets of training examples from suspected subpopulations, transform attributes in the training data or generate new ones, and choose interesting ways to substitute one experiment’s set of attributes with another. Automatic hydration pattern predictors are of both theoretical and practical interest to DNA crystallographers, because they can speed up a labor intensive process, and because the extracted rules add to the knowledge of what determines DNA hydration.