In our experience, leafy greens will keep for up to 5 days in the refrigerator if they are kept from drying out. This works well with a special Bio-Fresh compartment in the refrigerator. Alternatively, you can use water to keep the leafy vegetables fresh. To do this, soak a kitchen towel in water, wring it out and wrap ingredients in it. Herbs and smaller leafy greens like postelein or spinach are best stored in a plastic bag or storage box (Pro-tip: add a few splashes of water or a damp paper towel). Another tip for garden herbs: remove the rubber that holds them together.