Vegetables in general do not tend to be rich in iron, however some garden greens are calcium-rich. Grape leaves and lambs quarters top the list, though grape leaves are used more as a condiment and lambs quarters is not commercially available, though can be foraged in many areas in the wild. Collards, spinach, and kale are widely available greens that are high in calcium.
However, keep in mind that with all of these calcium-rich greens, your best strategy is to prepare them to reduce the calcium inhibitors, notably oxalic acid. Boiling them and discarding the boiling water is your best bet. You will discard some other nutrients in the boiling water, but you will absorb more calcium in your greens. Check out our article on reducing oxalic acid in your food.
Calcium in Common Vegetables
For information on the calcium content of common vegetables, explore these pages on our website: