Kales and collards are good year round, but are best after a cold spell. They develop sweetness after the cold.
The leaves should be supple and seem succulent rather than leathery.
For Russian kale, choose bunches that have the largest leaf to stem ratio you can find while avoiding “mature” plants with leathery leaves.
Stemming Russian kale can be a lot of work. Try using your fingers first, and if that doesn’t work, use a sharp paring knife.
Use your fingers to strip leaves from stems for curly kale and Lacinato. Make a ring of your thumb and index finger, place the middle joint of the index finger over the top of the stem near the base and grasp the base with the other hand, then pull the “ring” up the length of the stem. This should work, but if not, use a thin sharp knife.
To store winter greens, wrap in paper towels and place in a plastic bag or a large plastic box. Russian kale has the shortest shelf life of 3-5 days, collards next with 4-7 days, then lacinato and curly kale with up to 8 or 9 days. Before storing, I strip the leaves from the collards, then stack and roll them and put into the box in the refrigerator. Curly kale is stripped and between paper towels and placed in the plastic box or bagged with plenty of air in the bag if the box is full. Prepping the leafy greens and kale before storage speeds up making dinner during the week. To use, just submerge in a large bowl of cold water and shake to remove dirt. Lift the leaves out of the water, and repeat. Cut up and cook.
If you have curly kale or collards that look limp or tired, soak leves in cold water for ten minutes to revive them.
When choosing Lacinato kale, look for leaves that are not too shiny, nor too “crisp” in texture. I find these cook up stringy, and no amount of cooking seems to break this texture down.
Curly kale and Cavolo Nero or Lacinato are great in leftovers. Use in soups or make into a gratin or frittata.