What is the proper method to store green onions? Additionally, how long can it be stored in the chill chest?
The easiest thing to do is to chop them up, and preserve them in an acidic solution that you allow to ferment a little. Then, just keep it in the fridge as long as you like. Additionally, the onions will become tastier, easier to digest and will have an improved nutritional profile.
The acidic solution can be any mixture of water with salt, sugar, vinegar, spices, whey, yogurt, wine, beer, lemon juice, etc...The options are endless. This is called your brine and people have been using this method of preservation for millions of years.
As far as storing fresh onions, your best bet is to keep them in the refrigerator's crisper drawer which helps keep vegetables fresher longer.
I wash them and take off the outer skin part and cut off the roots, of course. I chop them into half inch pieces. Put them in a tupperware with a paper towel underneath. Put the lid on and put them in the fridge. Keep it loose, don't stuff them in there. I sprinkle them on everything I eat. Change your paper towel if it gets moist.
Lately I have been putting them in a glass with an inch or so of water in it, loosely covering them with a plastic bag, and putting them upright on a shelf in my fridge. I've found that they can easily stay fresh this way for a week or two provided I change the water sometimes (or add more when necessary) and occasionally shake out any condensation that may accumulate on the bag.
Have you ever tried dehydration method of preserving herbs?
Green onions don't lose their flavour and colour if dried properly, and they last for long time if stored properly in airtight container.
Try drying them even if you don't own a dehydrator it is simple. Just chop them up in cubes, put some baking paper on a tray, spread the chopped pieces on the paper and let them in an oven with its fan turned on. Or simply leave the tray in cool corner of your kitchen.