HOP (Ger. Hopfen, Fr. houblon), Humulus Lupulus, L., an herbaceous twining plant, belonging to the natural order Cannabinaceae, which is by some botanists included in the larger group called Urticaceae by Endlicher. It is of common occurrence in hedges and thickets in the southern counties of England, but is believed not to be native in Scotland. On the European continent it is distributed from Greece to Scandinavia, and extends through the Caucasus and Central Asia to the Altai Mountains. It is common, but doubtfully indigenous, in the northern and western states of North America, and has been introduced into Brazil, Australia and the Himalayas.
It is a perennial plant, producing annually several long twining roughish striated stems, which twist from left to right, are often 15 to 20 ft. long and climb freely over hedges and bushes. The roughness of stem and leaves is due to lines of strong hooked hairs, which help the plant to cling to its support. The leaves are stalked, opposite, 3-5 lobed, and coarsely serrate, and bear a general resemblance to those of the vine, but are, as well as the whole plant, rough to the touch; the upper leaves are sometimes scarcely divided, or quite entire. The stipules are between the leaf-stalks, each consisting of two lateral ones united, or rarely with the tips free. The male and female flowers are produced on distinct plants. The male inflorescence (fig. 1, A) forms a panicle; the flowers consist of a small greenish five-parted perianth (a) enclosing five stamens, whose anthers (b) open by terminal slits. The female inflorescence (fig. 1, B) is less conspicuous in the young state. The catkin or strobile consists of a number of small acute bracts, with two sessile ovaries at their base, each subtended by a rounded bractlet (c). Both the bracts and bractlets enlarge greatly during the development of the ovary, and form, when fully grown, the membranous scales of the strobile (fig. 2, a); they are known as “petals” by hop-growers. The bracts can then only be distinguished from the bractlets by being rather more acute and more strongly veined. The perianth (fig. 1, d) is short, cup-shaped, undivided and closely applied to the ovary, which it ultimately encloses. In the young strobile the two purple hairy styles (e) of each ovary project beyond the bracts. The ovary contains a single ovule (fig. 1. f) which becomes in the fruit an exalbuminous seed, containing a spirally-coiled embryo (fig. 2, b). The light dusty pollen is carried by the wind from the male to the female flowers.
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| Fig. 1.—Male (A) and Female (B) Inflorescence of the Hop. |
The ovary and the base of the bracts are covered with a yellowish powder, consisting of minute sessile grains, called lupulin or lupulinic glands. These glands (fig. 2, c) are from 1260 to 1140 in. in diameter, like flattened subovate little saucers in shape, and attached to a short pedicel. The upper or hemispherical portion bears a delicate continuous membrane, the cuticle, which becomes raised by the secretion beneath it of the yellowish lupulin. The stalk is not perceptible in the gland as found in commerce. When fresh the gland is seen to be filled with a yellowish or dark brown liquid; this on drying contracts in bulk and forms a central mass. It is to these lupulinic glands that the medicinal properties of the hop are chiefly due. By careful sifting about 1 oz. may be obtained from 1 ℔ of hops, but the East Kent variety is said to yield more than the Sussex hops.
In hop gardens a few male plants, usually three or four to an acre, are sometimes planted, that number being deemed sufficient to fertilize the female flowers. The blossoms are produced in August, and the strobiles are fit for gathering from the beginning of September to the middle of October, according to the weather.
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| Fig. 2.—Fruit of Hop. |
The cultivation of hops for use in the manufacture of beer dates from an early period. In the 8th and 9th centuries hop gardens, called “humularia” or “humuleta,” existed in France and Germany. Until the 16th century, however, hops appear to have been grown in a very fitful manner, and to a limited extent, generally only for private consumption; but after the beginning of the 17th century the cultivation increased rapidly. The plant was introduced into England from Flanders in 1525; and in America its cultivation was encouraged by legislative enactments in 1657. Formerly several plants were used as well as hops to season ale, hence the name “alehoof” for Nepeta Glechoma, and “alecost” for Balsamita vulgaris. The sweet gale, Myrica Gale, and the sage, Salvia officinalis, were also similarly employed. Various hop substitutes, in the form of powder, have been offered in commerce of late years, most of which appear to have quassia as a chief ingredient. The young tender tops of the hop are in Belgium cut off in spring and eaten like asparagus, and are forced from December to February.
Medical Use.—The principal constituents of the strobiles are lupulin, one of the few liquid alkaloids; lupulinic acid, a bitter crystalline body, soluble in ether, which is without any other pharmacological action than that common to bitter substances; Valerol, a volatile oil which in old hops undergoes a change to the malodorous body valerianic acid; resin; trimethylamine; a peculiar modification of tannin known as humulotannic acid; and a sesqui-terpene. The British pharmacopoeia contains two preparations of the strobiles,—an infusion (dose, 1-2 oz.) and a tincture (dose, 12-1 drachm). The glands obtained from the strobiles are known in pharmacy as lupulin, a name which tends to confusion with that of the alkaloid. They occur in commerce as a bright yellow-brown powder, seen under a lens to consist of minute glandular particles. The dose of this so-called lupulin is 2-5 grains. From it there is prepared the Tinctura Lupulinae of the United States pharmacopoeia, which is given in doses of 10-60 minims. Furthermore, there are prepared hop pillows, designed to procure sleep; but these act, when at all, mainly by suggestion. The pharmacological action of hops is determined first by the volatile oil they contain, which has the actions of its class. Similarly the lupulinic acid may act as a bitter tonic. The preparations of hops, when taken internally, are frequently hypnotic, though unfortunately different specimens vary considerably in composition, none of the preparations being standardized. It is by no means certain whether the hypnotic action of hops is due to the alkaloid lupulin or possibly to the volatile oil which they contain. Medical practice, however, is acquainted with many more trustworthy and equally safe hypnotics. The bitter acid of hops may endow beer containing it with a certain value in cases of impaired gastric digestion, and to the hypnotic principle of hops may partly be ascribed—as well as to the alcohol—the soporific action of beer in the case of some individuals.
Hop Production in England[1]
The cultivation of hops in the British Isles is restricted to England, where it is practically confined to half-a-dozen counties—four in the south-eastern and two in the west-midland districts. In 1901 the English crop was reported by the Board of Agriculture to occupy 51,127 acres. The official returns as to acreage do not extend back beyond 1868, in which year the total area was reported to be 64,488 acres. The largest area recorded since then was 71,789 acres in 1878; the smallest was 44,938 acres in 1907. The extent to which the areas of hops in the chief hop-growing counties vary from year to year is sufficiently indicated in Table I., which shows the annual acreages over a period of thirteen years, 1895 to 1907. The proportions in which the acres of hops are distributed amongst the counties concerned vary but little year by year, and as a rule over 60% belongs to Kent.
Table I.—Hop Areas of England 1895 to 1907. Acres.
| Kent. | Hereford. | Sussex. | Worcester. | Hants. | Surrey. | |
| 1895 | 35,018 | 7553 | 7489 | 4024 | 2875 | 1783 |
| 1896 | 33,300 | 6895 | 5908 | 3800 | 2494 | 1623 |
| 1897 | 31,661 | 6542 | 5174 | 3591 | 2306 | 1416 |
| 1898 | 30,941 | 6651 | 4829 | 3567 | 2263 | 1313 |
| 1899 | 31,988 | 7227 | 4949 | 3788 | 2319 | 1388 |
| 1900 | 31,514 | 7287 | 4823 | 3964 | 2231 | 1300 |
| 1901 | 31,242 | 7497 | 4800 | 4029 | 2133 | 1232 |
| 1902 | 29,649 | 6915 | 4541 | 3779 | 2003 | 969 |
| 1903 | 29,933 | 6851 | 4454 | 3697 | 1920 | 901 |
| 1904 | 29,841 | 6767 | 4474 | 3752 | 1900 | 877 |
| 1905 | 30,655 | 6851 | 4647 | 3807 | 1978 | 843 |
| 1906 | 29,296 | 6481 | 4379 | 3672 | 1939 | 777 |
| 1907 | 28,169 | 6143 | 4243 | 3622 | 1842 | 744 |
Less than 200 acres in all are annually grown in the other hop-growing counties of England, these being Shropshire, Gloucestershire and Suffolk.
The average yield per acre in cwt. in the six counties during the decade 1897 to 1906 was as follows:—
Table II.
| Kent. | Hereford. | Sussex. | Worcester. | Hants. | Surrey. |
| 9.31 | 7.14 | 9.41 | 7.79 | 8.78 | 7.23 |
Table III. shows the average acreage, yield and total home
produce of England during the decades 1888–1897 and 1898–1907.
Table III.
| Periods. | Average Annual Acreage. | Average Annual Yield per acre (cwt.). | Average Annual Home Produce (cwt.). |
| 1888–1897 | 56,370 | 7.76 | 438,215 |
| 1898–1907 | 48,841 | 8.84 | 434,567 |
The wide fluctuations in the home production of hops are worthy of note, as they exercise a powerful influence upon market prices. The largest crop between 1885, the first year in which figures relating to production were collected, and 1907 was that of 776,144 cwt. in 1886, and the smallest that of 281,291 cwt. in 1888, the former being more than 212 times the size of the latter. The crop of 1899, estimated at 661,373 cwt., was so large that prices receded to an extent such as to leave no margin of profit to the great body of growers, whilst some planters were able to market the crop only at a loss. The calculated annual average yields per acre over the years 1885 to 1907 ranged between 12.76 cwt. in 1899 and 4.81 cwt. in 1888. No other staple crop of British agriculture undergoes such wide fluctuations in yield as are here indicated, the size of the crop produced bearing no relation to the acreage under cultivation. For example, the 71,327 acres in 1885 produced only 509,170 cwt., whereas the 51,843 acres in 1899 produced 661,373 cwt.—19,484 acres less under crop yielded 152,203 cwt. more produce.
Comparing the quantities of home-grown hops with those of imported hops, of the total available for consumption about 70% on the average is home produce and about 30% is imported produce. The imports, however, do not vary so much as the home produce. Table IV. shows the average quantity of imports to and exports (home-grown) from Great Britain during the decades 1877–1886, 1887–1896 and 1897–1906.
Table IV.
| Periods. | Annual Average Imports (cwt.). | Annual Average Exports (cwt.). |
| 1877–1886 | 215,219 | 10,805 |
| 1887–1896 | 194,966 | 9,437 |
| 1897–1906 | 186,362 | 14,808 |
The highest and lowest imports were 266,952 cwt. in 1885 and 145,122 cwt. in 1887, the latter in the year following the biggest home-grown crop on record. On a series of years the largest proportion of imports is from the United States.
During the twenty-five years 1881–1905 the annual values of the hops imported into England fluctuated between the wide limits of £2,962,631 in 1882 and £427,753 in 1887. In five other years besides 1882 the value exceeded a million sterling. The annual average value over the whole period was £921,000, whilst the annual average import was 194,000 cwt., consequently the average value per cwt. was nearly £4, 15s., which is approximately the same as that of the exported product. The quantities and values of the imported hops that are again exported are almost insignificant.
Hop Production in the United States
The distribution of the area of hop-cultivation in the United States showed great changes during the last decades of the 19th and the first decade of the 20th century. During the earlier portion of that period New York was the chief hop-growing state of the Union, but toward the end of it a great extension of hop-growing took place on the Pacific coast (in the states of Oregon, California and Washington), where the richness of the soil and mildness of the climate are favourable to the bines.
The average annual produce of hops in the United States from 1900 to 1906 was 423,471 cwt.; of this quantity 80% was raised in the three states of the Pacific coast, where the yield per acre is much larger than in New York. In the latter state the yield does not appear to exceed 5 or 6 cwt. per acre, whereas in Oregon it is 9 or 10 cwt., and in Washington and California from 12 to 14 cwt. The average annual export (chiefly to Great Britain) in the years from 1899 to 1905 was 108,400 cwt.; the average import (chiefly from Germany) is about 50,000 cwt.
Hop Cultivation
As the county of Kent has always taken the lead in hop-growing in England, and as it includes about two-thirds of the hop acreage of the British Isles, the recent developments in hop cultivation cannot be better studied than in that county. They were well summarized by Mr Charles Whitehead in his sketch of the agriculture of Kent,[2] wherein he states that the hop grounds—or hop gardens, as they are called in Kent—of poor character and least suitable for hop production have been gradually grubbed since 1894, on account of large crops, the importation of hops and low prices. At the beginning of the 19th century there were 290 parishes in Kent in which hops were cultivated. A century later, out of the 413 parishes in the county, as many as 331 included hop plantations. The hops grown in Kent are classified in the markets as “East Kents,” “Bastard East Kents,” “Mid Kents” and “Wealds,” according to the district of the county in which they are produced. The relative values of these four divisions follow in the same order, East Kents making the highest and Wealds the lowest rates. These divisions agree in the main with those defined by geological formations. Thus, “East Kents” are grown upon the Chalk, and especially on the outcrop of the soils of the London Tertiaries upon the Chalk. “Bastard East Kents” are produced on alluvial soil and soils formed by admixtures of loam, clay-loams, chalk, marl and clay from the Gault, Greensand and Chalk formations. “Mid Kents” are derived principally from the Greensand soils and outcrops of the London Tertiaries in the upper part of the district. “Wealds” come from soils on the Weald Clay, Hastings Sand and Tunbridge Wells Sand. As each “pocket” of hops must be marked with the owner’s name and the parish in which they were grown, buyers of hops can, without much trouble, ascertain from which of the four divisions hops come, especially if they have the map of the hop-growing parishes of England, which gives the name of each parish. There has been a considerable rearrangement of the hop plantations in Kent within recent years. Common varieties as Colegate’s, Jones’s, Grapes and Prolifics have been grubbed, and Goldings, Bramlings and other choice kinds planted in their places. The variety known as Fuggle’s, a heavy-cropping though slightly coarse hop, has been much planted in the Weald of Kent, and in parts of Mid Kent where the soil is suitable. In very old hop gardens, where there has been no change of plant for fifty or even one hundred years in some instances, except from the gradual process of filling up the places of plants that have died, there has been replanting with better varieties and varieties ripening in more convenient succession; and, generally speaking, the plantations have been levelled up in this respect to suit the demand for bright hops of fine quality. A recent classification[3] of the varieties of English hops arranges them in three groups: (1) early varieties (e.g. Prolific, Bramling, Amos’s Early Bird); (2) mid-season or main-crop varieties (e.g. Farnham Whitebine, Fuggle’s, Old Jones’s, Golding); (3) late varieties (e.g. Grapes, Colgate’s).
The cost of cultivating and preparing the produce of an acre of hop land tends to increase, on account of the advancing rates of wages, the intense cultivation more and more essential, and the necessity of freeing the plants from the persistent attacks of insects and fungi. In 1893 Mr Whitehead estimated the average annual cost of an acre of hop land to be £35, 10s., the following being the items:—
| Manure (winter and summer) | £6 | 10 | 0 |
| Digging | 0 | 19 | 0 |
| Dressing (or cutting) | 0 | 6 | 0 |
| Poling, tying, earthing, ladder-tying, stringing, lewing | 2 | 3 | 0 |
| Shimming, nidgeting, digging round and hoeing hills | 3 | 0 | 0 |
| Stacking, stripping, making; bines, &c. | 0 | 17 | 0 |
| Annual renewal of poles | 2 | 10 | 0 |
| Expense of picking, drying, packing, carriage, sampling, | |||
| selling, &c., on average crop of, say, 7 cwt. per acre | 10 | 5 | 0 |
| Rent, rates, taxes, repairs of oast and tacks, interest on capital | 6 | 0 | 0 |
| Sulphuring | 1 | 0 | 0 |
| Washing (often two, three or four times) | 2 | 0 | 0 |
| Total | £35 | 10 | 0 |
Seven years later the average cost per acre in Kent had risen to quite £37.
The hops in Kent are usually planted in October or November, the plants being 6 ft. apart each way, thus giving 1210 hills or plant-centres per acre. Some planters still grow potatoes or mangels between the rows the first year, as the plants do not bear much until the second year; but this is considered to be a mistake, as it encourages wire-worm and exhausts the ground. Many planters pole hop plants the first year with a single short pole, and stretch coco-nut-fibre string from pole to pole, and grow many hops in the first season. Much of the hop land is ploughed between the rows, as labour is scarce, and the spaces between are dug afterwards. It is far better to dig hop land if possible, the tool used being the Kent spud. The cost of digging an acre ranges from 18s. to 21s. Hop land is ploughed or dug between November and March. After this the plants are “dressed,” which means that all the old bine ends are cut off with a sharp curved hop-knife, and the plant centres kept level with the ground.
Manuring.—Manure is applied in the winter, and dug or ploughed in. London manure from stables is used to an enormous extent. It comes by barge or rail, and is brought from the wharves and stations by traction engines; it costs from 7s. 6d. to 9s. per load. Rags, fur waste, sprats, wool waste and shoddy are also put on in the winter. In the summer, rape dust, guano, nitrate of soda and various patent hop manures are chopped in with the Canterbury hoe. Fish guano or desiccated fish is largely used; it is very stimulating and more lasting than some of the other forcing manures.
The recent investigations into the subject of hop-manuring made by Dr Bernard Dyer and Mr F. W. E. Shrivell, at Golden Green, near Tonbridge, Kent, are of interest. In the 1901 report[4] it was stated that the object in view was to ascertain how far nitrate of soda, in the presence of an abundant supply of phosphates and potash, is capable of being advantageously used as a source of nitrogenous food for hops. An idea long persisted among hop-growers that nitrate of soda was an unsafe manure for hops, being likely to produce rank growth of bine at the expense of quality and even quantity of hops. During recent years, however, owing very largely to the results of these experiments, and of corresponding experiments based upon these, which have been carried out abroad, hop farmers have much more freely availed themselves of the aid of this useful manure; and there is little doubt that the distrust of nitrate of soda as a hop manure which has existed in the past has been largely due to the fact that nitrate of soda, like many other nitrogenous manures, has often been misused (1) by being applied without a sufficient quantity of phosphates and potash, or (2) by being applied too abundantly, or (3) by being applied too late in the season, with the result of unduly delaying the ripening period. On most of the experimental plots nitrate of soda (in conjunction with phosphates and potash) has been used as the sole source of nitrogen; but it is, of course, not be to supposed that any hop-grower would use year after year, as is the case on some of the plots, nothing but phosphates, potash and nitrate of soda. Miscellaneous feeding is probably good for plants as well as for animals, and there is a large variety of nitrogenous manures at the disposal of the hop-farmer, to say nothing of what, in its place, is one of the most valuable of all manures, namely, home-made dung. These experiments were begun in 1894 with a new garden of young Fuggle’s hops. A series of experimental plots was marked out, each plot being one-sixth of an acre in area. The plots run parallel with one another, there being four rows of hills in each. The climate of the district is very dry.
Weight of Kiln-dried Fuggle’s Hops per Acre.
| Plot. | Annual Manuring per Acre. | 1896 | 1897 | 1898 | 1899 | 1900 | Average of 5 Years. |
| Cwt. | Cwt. | Cwt. | Cwt. | Cwt. | Cwt. | ||
| A | Phosphates and potash | 1312 | 712 | 814 | 2014 | 8 | 1112 |
| B | Phosphates, potash and 2 cwt. nitrate of soda | 1612 | 914 | 1014 | 2214 | 934 | 1312 |
| C | Phosphates, potash and 4 cwt. nitrate of soda | 1612 | 12 | 1212 | 23 | 11 | 15 |
| D | Phosphates, potash and 6 cwt. nitrate of soda | 1514 | 13 | 13 | 2212 | 1012 | 1434 |
| E | Phosphates, potash and 8 cwt. nitrate of soda | 15 | 1312 | 1514 | 2312 | 11 | 1512 |
| F | Phosphates, potash and 10 cwt. nitrate of soda | 15 | 13 | 15 | 2412 | 1012 | 1534 |
| X | 30 loads (about 15 tons) London dung | 13 | 8 | 934 | 2412 | 1034 | 1334 |
The table given above shows the annual yield of hops per acre on each plot, and also the average for each plot over the five years 1896–1900.
In only one year did the very large dressing of 10 cwt. of nitrate of soda per acre afford any better result than was produced by the less heavy dressing of 8 cwt. per acre, and this was in 1899, a season of such abundance and such low prices that it may be regarded as an abnormal season. If the effect of this one season on the average be eliminated, the best results, as regards quantity, were obtained on plot E, receiving 8 cwt. of nitrate of soda per acre. But plot C, with 4 cwt. only of nitrate of soda per acre, has been on the average not more than 12 cwt. per acre behind plot E.
Valuations of the hops made by merchants and factors show that, on the whole, the market quality of the produce is very little affected by manuring. Moreover, chemical investigation of the hops appears to indicate that the brewing quality is not in any constant or definite way influenced by the manuring, except where the quantity of nitrate of soda has amounted to the large dressing of 8 cwt. or more per acre, a quantity which in some seasons would seem to have been prejudicial, although in one season it happened that the highest brewing value appertained to a sample grown with as much as 10 cwt. per acre.
The results of modern investigation show that it is very largely to the presence and proportion of soft resin that hops owe their preservative value, although the quality of hops is by no means wholly dependent on this one feature. The resin percentages on the samples grown on the several plots in 1898, 1899 and 1900 were the following:—
| Plot. | Annual Manuring per Acre. | 1898 | 1899 | 1900 | |||
| Total Resin. | Soft Resin. | Total Resin. | Soft Resin. | Total Resin. | Soft Resin. | ||
| Per Cent. | Per Cent. | Per Cent. | Per Cent. | Per Cent. | Per Cent. | ||
| A | Phosphates and potash | 14.15 | 9.21 | 15.07 | 8.60 | 14.53 | 8.90 |
| B | Phosphates, potash and 2 cwt. nitrate of soda | 14.30 | 9.20 | 16.59 | 8.83 | 15.09 | 8.51 |
| C | Phosphates, potash and 4 cwt. nitrate of soda | 14.06 | 9.04 | 15.87 | 9.27 | 14.46 | 8.16 |
| D | Phosphates, potash and 6 cwt. nitrate of soda | 13.57 | 8.60 | 14.90 | 8.70 | 13.46 | 7.62 |
| E | Phosphates, potash and 8 cwt. nitrate of soda | 14.11 | 8.85 | 14.49 | 8.96 | 13.30 | 7.18 |
| F | Phosphates, potash and 10 cwt. nitrate of soda | 12.21 | 7.91 | 15.47 | 9.41 | 12.77 | 6.77 |
| X | 30 loads (about 15 tons) London dung | 13.93 | 8.66 | 14.92 | 8.80 | 14.78 | 9.07 |
The general results seem to show that the purchase of town dung for hops is not economical, unless under specially favourable terms as to cost of conveyance, and that it should certainly not be relied upon as a sufficient manure. Home-made dung is in quite a different position, as not only is it richer, but it costs nothing for railway carriage. As a source of nitrogenous manure, purchased dung is on the whole too expensive. There is a large variety of other nitrogenous manures in the market besides nitrate of soda, such, for instance as Peruvian and Damaraland guano, sulphate of ammonia, fish guano, dried blood, rape dust, furriers’ refuse, horn shavings, hoof parings, wool dust, shoddy, &c. All of these may in turn be used for helping to maintain a stock of nitrogen in the soil; and the degree to which manures of this kind have been recently applied in any hop garden will influence the grower in deciding as to the quantity of nitrate of soda he should use in conjunction with them, and also to some extent in fixing the date of its application.
Dressings of 8 or 10 cwt. of nitrate of soda per acre, such as are applied annually to plots E and F, would be larger than would be put on where the land has been already dressed with dung or with other nitrogenous manures; and even, in the circumstances under notice, although these plots have on the average beaten the others in weight, the hops in some seasons have been distinctly coarser than those more moderately manured—though in the dry season of 1899 the most heavily dressed plot gave actually the best quality as well as the greatest quantity of produce.
With regard to the application of nitrate of soda in case the season should turn out to be wet, present experience indicates that, on a soil otherwise liberally manured, 4 cwt. of nitrate of soda per acre applied not too late, would be a thoroughly safe dressing. In the case of neither dung nor any other nitrogenous fertilizers having been recently applied, there seems no reason for supposing that, even in a wet season, 6 cwt. of nitrate of soda per acre applied early would be otherwise than a safe dressing, considering both quantity and quality of produce. In conjunction with dung, or with the early use of other nitrogenous manures, such as fish, guano, rape dust, &c. it would probably be wise not to exceed 4 cwt. of nitrate of soda per acre.
As to the date of application, April or May is the latest time at which nitrate of soda should, in most circumstances, be applied, and probably April is preferable to May. The quantity used should be applied in separate dressings of not more than 2 cwt. per acre each, put on at intervals of a month. Where the quantity of nitrate of soda used is large, and constitutes the whole of the nitrogenous manure employed, the first dressing may, on fairly deep and retentive soils, be given as early as January; or, if the quantity used is smaller, say in February; while February will, in most cases, probably be early enough for the first dressing in the case of lighter soils. The condition of the soil and the degree and distribution of rainfall during both the previous autumn and the winter, as well as in the spring itself, produce such varying conditions that it is almost impossible to frame general rules.
The commonly accepted notion that nitrate of soda is a manure which should be reserved for use during the later period of the growth of the bine appears to be erroneous. The summer months, when the growth of the bine is most active, are the months in which natural nitrification is going on in the soil, converting soil nitrogen and the nitrogen of dung, guano, fish, rape dust, shoddy or other fertilizers into nitrates, and placing this nitrogen at the disposal of the plants; and it appears reasonable, therefore, to suppose that nitrate of soda will be most useful to the hops at the earlier stages of their growth, before the products of that nitrification become abundant. This would especially be so in a season immediately following a wet autumn and winter, which have the effect of washing away into the drains the residual nitrates not utilized by the previous crop.
The necessity, whether dung is used or not, and whatever form of nitrogenous manure is employed, of also supplying the hops with an abundance of phosphates, cannot be too strongly urged. The use of phosphates for hops was long neglected by hop-planters, and even now there are many growers who do not realize the full importance of heavy phosphatic manuring. On soils containing an abundance of lime no better or cheaper phosphatic manure can be used than ordinary superphosphate, of which as much as 10 cwt. per acre may be applied without the slightest fear of harm. But if the soil is not decidedly calcareous—that is to say, if it does not effervesce when it is stirred up with some diluted hydrochloric (muriatic) acid—bone dust, phosphatic guano or basic slag should be used as a source of phosphates, at the rate of not less than 10 cwt. per acre. On medium soils, which, without being distinctly calcareous, nevertheless contain a just appreciable quantity of carbonate of lime, it is probably a good plan to use the latter class of manures, alternately with superphosphate, year and year about; but it is wise policy to use phosphates in some form or other every year in every hop garden. They are inexpensive, and without them neither dung, nitrate of soda, ammonia salts nor organic manures can be expected to produce both a full vigorous growth of bine and at the same time a well-matured crop of full-weighted, well-conditioned hops.
The use of potash salts, on most soils, is probably not needed when good dung is freely used; but where this is not the case it is safer in most seasons and on most soils to give a dressing of potash salts. On some soils their aid should on no account be dispensed with.
Experiments in hop-manuring have also been conducted in connexion with the South-Eastern Agricultural College, Wye, Kent. The main results have been to demonstrate the necessity of a liberal supply of phosphates, if the full benefit is to be reaped from applications of nitrogenous manure.
Tying, Poling and Picking.—Tying the bines to the poles or strings is essentially women’s work. It was formerly always piecework, each woman taking so many acres to tie, but it is found better to pay the women 1s. 8d. to 2s. per day, that they may all work together, and tie the plants in those grounds where they want tying at once. The new modes of poling and training hop plants have also altered the conditions of tying.
Many improvements have been made in the methods of poling and training hops. Formerly two or three poles were placed to each hop-hill or plant-centre in the spring, and removed in the winter, and this was the only mode of training. Recently systems of training on wires and strings fastened to permanent upright poles have been introduced. One arrangement of wires and strings much adopted consists of stout posts set at the end of every row of hop-hills and fastened with stays to keep them in place. At intervals in each row a thick pole is fixed. From post to post in the rows a wire is stretched at a height of 12 ft. from the ground, another about 6 ft. from the ground, and another along the tops of the posts, so that there are three wires. Hooks are clipped on these wires at regular intervals, and coco-nut-fibre strings are threaded on them and fastened from wire to wire, and from post to post, to receive the hop bines. The string is threaded on the hooks continuously, and is put on those of the top wire with a machine called a stringer. There are several methods of training hops with posts or stout poles, wire and string, whose first cost varies from £20 to £40 per acre. The system is cheaper in the long run than that of taking down the poles every year, and the wind does not blow down the poles or injure the hops by banging the poles together. In another method, extensively made use of in Kent and Sussex, stout posts are placed at the ends of each row of plants, and, at intervals where requisite, wires are fastened from top to top only of these posts, whilst coco-nut-fibre strings are fixed by pegs to the ground, close to each hop-stock, whence they radiate upwards for attachment to the wires stretching between the tops of the posts. This method is more simple and less expensive than the system first described, its cost being from £24 to £28 per acre. In this case the plants require to be well “lewed,” or sheltered, as the strings being so light are blown about by the wind. These methods are being largely adopted, and, together with the practice of putting coco-nut-fibre strings from pole to pole in grounds poled in the old-fashioned manner, are important improvements in hop culture, which have tended to increase the production of hops. Where the old system of poling with two or three poles is still adhered to they are always creosoted, most growers having tanks for the purpose; and, in the new methods of poling, the posts and poles are creosoted, dipped or kyanized.
At Wye College, Kent, different systems of planting and training have been tried, the alleys varying in width from 10 ft. down to 5 ft., and the distance between the hills varying quite as widely, so that the number of hills to the acre has ranged from 1210 down to 660. The biggest crop was secured on the plot where hills were 8 ft. apart each way. As a rule, indeed, a wide alley and abundant space between the plants, thus allowing the hops plenty of air and light, produced the best results, besides effecting some saving in the cost of cultivation, as there were only 660 or 680 hills per acre. Of the various methods of training, the umbrella system gave the biggest crop in each of the three years, 1899, 1900, 1901; and it seemed to be the best method, except in seasons when washing was required early, in which case the plants were not so readily cleared of vermin.
Much attention is required to keep the bines in their places on the poles, strings or wire, during the summer. This gives employment to many women, for whose service in this and fruit-picking there is considerable demand, and a woman has no trouble in earning from 1s. 6d. to 1s. 10d. per day from April till September at pleasant and not very arduous labour. The hop-picking follows, and at this women sometimes get 4s. and even 5s. per day. This is the real Kent harvest, which formerly lasted a month or five weeks. Now it rarely extends beyond eighteen days, as it is important to secure the hops before the weather and the aphides, which almost invariably swarm within the bracts of the cones, discolour them and spoil their sale, as brewers insist upon having bright, “coloury” hops. Picking is better done than was formerly the case. The hops are picked more singly, and with comparatively few leaves, and the pickers are of a somewhat better type than the rough hordes who formerly went into Kent for “hopping.” Kent planters engage their pickers beforehand, and write to them, arranging the numbers required and the date of picking. Many families go into Kent for pea- and fruit-picking and remain for hop-picking. Without this great immigration of persons, variously estimated at between 45,000 and 65,000, the crops of hops could not be picked; and fruit-farmers also would be unable to get their soft fruit gathered in time without the help of immigrant hands. The fruit-growers and hop-planters of Kent have greatly improved the accommodation for these immigrants.
Concerning the general question as to the advisability or otherwise of cutting the hop bine at the time of picking, A.D. Hall has ascertained experimentally that if the bine is cut close to the ground at a time when the whole plant is unripe there are removed in the bine and leaves considerable quantities of nitrogen, potash and phosphoric acid which would have returned to the roots if the bine had not been cut until ripe. The plant, therefore, would retain a substantial store of these constituents for the following year’s growth if the bine were left. Chemical analyses have shown that about 30 ℔ of nitrogen per acre may be saved by allowing the bines to remain uncut, this representing practically one-third of the total amount of nitrogen in the hops, leaf and bine together. There are also from 25 ℔ to 30 ℔ of potash in the growth, of which nine-tenths would return to the roots, with about half the phosphoric acid and a very small proportion of the lime. It has been demonstrated that by the practice of cutting the bines when the hops are picked the succeeding crop is lessened to the extent of about one-tenth. As to stripping off the leaves and lower branches of the plant, it was found that this operation once reduced the crop 10% and once 20%, but that in the year 1899 it did not affect the crop at all. The inference appears to be that when there is a good crop it is not reduced by stripping, but that when there is less vigour in the plant it suffers the more. Hence, it would seem advisable to study the plant itself in connexion with this matter, and to strip a little later, or somewhat less, than usual when the bine is not healthy.
Drying.—After being picked, the hops are taken in pokes—long sacks holding ten bushels—to the oasts to be dried. The oasts are circular or square kilns, or groups of kilns, wherein the green hops are laid upon floors covered with horsehair, under which are enclosed or open stoves or furnaces. The heat from these is evenly distributed among the hops above by draughts below and round them. This is the usual simple arrangement, but patent processes are adopted here and there, though they are by no means general. The hops are from nine to ten hours drying, after which they are taken off the kiln and allowed to cool somewhat, and are then packed tightly into “pockets” 6 ft. long and 2 ft. wide, weighing 112 cwt., by means of a hop-pressing machine, which has cogs and wheels worked by hand. Of late years more care has been bestowed by some of the leading growers upon the drying of hops, so as to preserve their qualities and volatile essences, and to meet the altered requirements of brewers, who must have bright, well-managed hops for the production of light clear beers for quick draught. The use, for example, of exhaust fans, recently introduced, greatly facilitates drying by drawing a large volume of air through the hops; and as the temperature may at the same time be kept low, the risk of getting overfired samples is considerably reduced, though not entirely obviated. The adoption of the roller floor is another great advance in the process of hop-drying, for this, used in conjunction with a raised platform for the men to stand on when turning, prevents any damage from the feet of the workmen, and reduces the loss of resin to a minimum. The best results are obtained when exhaust fans and the roller floor are associated together. In such cases the roller floor, which empties its load automatically, pours the hop cones into the receiving sheets in usually as whole and unbroken a condition as that in which they went on to the kiln.
Pests of the Hop Crop.—In recent years the difficulties attendant upon hop cultivation have been aggravated, and the expenses increased, by regularly recurring attacks of aphis blight—due to the insect Aphis (Phorodon) humuli—which render it necessary to spray or syringe every hop plant, every branch and leaf, with insecticidal solutions three or four times, and sometimes more often, in each season. Quassia and soft-soap solutions are usually employed; they contain from 4 ℔ to 8 ℔ of soft soap, and the extract of from 8 ℔ to 10 ℔ of quassia chips to 100 gallons of water. The soft soap serves as a vehicle to retain the bitterness of the quassia upon the bines and leaves, making them repulsive to the aphides, which are thus starved out. Another pest, the red spider, Tetranychus telarius—really one of the “spinning mites”—is most destructive in very hot summers. Congregating on the under surfaces of the leaves, the red spiders exhaust the sap and cause the leaves to fall, producing the effect known in Germany as “fire-blast.” The hop-wash of soft soap and quassia, so effective against aphis attack, is of little avail in the case of red spider. Some success, however, has attended the use of a solution containing 8 ℔ to 10 ℔ of soft soap to 100 gallons of water, with three pints of paraffin added. It is necessary to apply the washes with great force, in order to break through the webs with which the spiders protect themselves. Hop-washing is done by means of large garden engines worked by hand, but more frequently with horse engines. Resort is sometimes had to steam engines, which force the spraying solution along pipes laid between the rows of hops.
Mould or mildew is frequently the source of much loss to hop-planters. It is due to the action of the fungus Podosphaera castagnei, and the mischief is more especially that done to the cones. The only trustworthy remedy is sulphur, employed usually in the form of flowers of sulphur, from 40 ℔ to 60 ℔ per acre being applied at each sulphuring. The powder is distributed by means of a machine drawn by a horse between the rows. The sulphur is fed from a hopper into a blast-pipe, whence it is driven by a fan actuated by the travelling wheels, and falls as a dense, wide-spreading cloud upon the hop-bines. The first sulphuring takes place when the plants are fairly up the poles, and is repeated three or four weeks later; and even again if indications of mildew are present. It may be added that sulphur is also successfully employed in the form of an alkaline sulphide, such as solution of “liver of sulphur,” a variety of potassium sulphide. (W. Fr.)