This section is from the book "Commercial Gardening Vol3", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Apart from its value as a timber and ornamental tree, the Walnut (Juglans regia) is also a valuable fruit tree. It is not, however, grown as a crop in the same sense that other fruit trees are, but is usually found dotted about here and there in open places in market gardens and large pleasure grounds. In a wild state the Walnut is found from south Europe eastwards to the Himalayas, Persia, and Upper Burma, and in some of these countries is said to attain an age of 300 to 400 years. In favoured parts of Britain it attains a height of over 60 ft., and a diameter of 2 to 4 ft. It has a whitish-grey bark, and leaves divided into from five to thirteen smooth lance-shaped leaflets, which in a young or seedling stage are serrate on the margins. The male flowers are borne in drooping catkins 2-5 in. long, on the previous year's wood, and the female blossoms are borne at the tips of the same shoots in clusters varying in number, but usually two or three, as shown in the sketch (fig. 396). Several fine examples are to be met with in the older market gardens of Middlesex, and also in parts of Bucks and Hants. On well-established trees the crop of nuts will vary from 6 or 7 bus. to as many as 60, according to the season and soil. A bushel of walnuts with the husks on will yield about 1/2 bus. of nuts; and 1 bus. will weigh about 40 lb. and contain about 1000 nuts. A fair average price is about 6s. a bushel, but this price is improved upon when the nuts are retailed at ten a penny. English walnuts always fetch higher prices than foreign ones, of which about 70,000 bus. are imported annually. The nuts are gathered in a ripe and unripe stage. In the latter case they are picked about the first or second week of July, while the skins are still tender, and in this state the green young fruits are largely used for pickling. When ripe, in autumn, the nuts are usually beaten from the trees with long supple ash rods, and there is an impression that this is the best possible way, and that the trees themselves are benefited by the thrashing. Indeed there is an old saying to the effect that -" A woman, a dog, and a Walnut tree, The more you thrash them, the better they be ".
The husks, if placed in tubs, with a little salt added, and pressed under heavy weights, make an excellent ketchup, the juice being strained off and used neat or diluted with some pure boiled vinegar.
The Walnut flourishes in a rich sandy loam, and may be raised from seeds which are sown as soon as ripe, or in spring, after being stratified in sand during the winter to preserve the vitality. Besides the Common Walnut the following are also met with: Highflyer, early, thin-shelled; Large Double, with very large double fruits; Thin Shelled, double, early, with a very thin shell, and fine flavour.