Blanching of Endives can be achieved in a number of ways. In France, where Endives are very popular, commercial growers often use purpose-made Endive-blanchers that are shaped like a domed dinner-plate. The blancher is simply placed on top of the growing plant. You can also get blanchers that are a bit like Rhubarb-forcers, normally made of terracotta, that look like tall upside-down flower-pots. However, you can achieve much the same effect with a piece of string!
This is my technique: on a dry day (wet foliage rots quickly), gather all the leaves of the Endive together and tie a piece of soft string around the outside, not too tightly, but firmly enough to keep the leaves in place.
I normally secure the string with a bow knot, so that I can easily untie it to adjust the tension if necessary.
Apart from watering occasionally if necessary, all you have to do now is wait. Wait for about a week to ten days, by which time the inner leaves will be a pale yellow colour, at which point you cut off the plant at its base, discard the outer leaves, and eat the inner ones in your salad.
During the blanching period I sometimes untie the string briefly, just to check progress, and to remove any leaves that have rotted or gone mildewy - which can happen if the plant is wet and/or if the temperature is too high. My method is better for avoiding fungal growths than containing the whole plant in a pot-like Endive-blancher, because it allows better ventilation.
This next photo shows an overhead view of a plant that has been tied.
Compare it with this:
Of course this photo is of an immature plant, which is not yet ready for tying, but at least it demonstrates the star-shaped structure of the plant so that you can better understand how the tying-up operation works.
My final word on the subject is this: when your Endive is ready to eat, I suggest serving it with a nice sharp French Dressing (with lots of finely-diced Shallots in it) - or better still, a creamy Blue Cheese dressing. Foe Jane and me, blanched Endive is the classic accompaniment to a rack of Lamb, served with Gratin Dauphinois, so I think we'll be looking out for a suitable rack next time we go shopping...
