Prepare the leeks by rinsing them in cool water and cutting off any parts that have started to wilt or are discolored. Cut off the roots.
Trim the tough dark green parts off the top. Take as much as you want off, I don't mind them being a little tough, so I take about half off.
Cut the leeks however you would like. Sliced, chopped, chunked, it's really up to you and how you want to use them.
Put the leeks into bowl and cover with water. Drain and rinse, repeat 2-3 more times to remove the sand.
Use a salad spinner to remove excess water, or pat dry with a paper towel.
Spread the leeks out onto the dehydrator trays, breaking apart any clumps and trying not to overlap them too much. Alternatively, you can spread them out on a cookie sheet to dry in the oven.
Dehydrate between 122°-125°F for 8-10 hours.To dry in the oven: set it to it's lowest setting, at about 170°F for 4-5 hours. You may need to flip them half way in between.
The leeks are finished once they can be easily snapped in half.
Once the leeks are completely cool, store them in in an air tight container for about a year.*
You can turn this into a powder by grinding them in a blender, coffee grinder, or using a mortar and pestle.
Notes
* See my post to learn a little more about storing methods.