- Before harvesting, you should taste the leaf since garden sorrel leaves can get very strong and sour toward the end of their season. Garden sorrel leaves must be dried in a warm, dry place out of direct sunlight. They may be hung up or strewn on dry tea towels or even over fine-weave drying racks. Drying them too quickly makes them brittle and reduces their potency.
- The dried garden sorrel herb is not generally used in cooking, but is often only used medicinally. Nancy Arrowsmith, author of "Essential Herbal Wisdom: A Complete Exploration of 50 Remarkable Herbs," notes that sorrel has both diuretic properties and laxative properties. This means that it increases the rate of excreting water from the body through urination as well as assisting the movement of the bowels.
- A doctor should approve the use of any herb for medicinal purposes. Sorrel contains oxalates, a compound found in spinach and other culinary greens. While not hazardous in small doses, it is poisonous in large doses.
- To preserve sorrel for culinary uses, it is best canned or frozen instead of dried; this helps preserve the sour flavor. Freezing sorrel preserves more of the nutrients of the plant and is the simplest way to keep it from spoiling in storage. Either way, the leaves must be blanched first -- dipped in boiling water -- to help prevent spoilage.