Spinach salad has been on gourmet menus for many years.  Both spinach and chard are cool season crops and will 'bolt' or start to go to seed when the weather warms up too much for them.  Both are best used fresh or steamed lightly.  Freezing produces an acceptable result, but canning processing times turn the product too mushy for most peoples tastes.

Harvest spinach by picking some, but not all, of the  leaves from the plant.  Swiss chard grows in a rosette form and the outer leaves should be picked before they toughen and the stems get too thick.

To freeze, rinse with cool water several times to remove all dirt and possible bugs, then pat dry or drain very well.  Tear and chop into small pieces or slice thinly, and pack into ziplock freezer bags, squeezing out as much air as possible.