This section is from the book "The Gardener V2", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
To the northern parts of Asia we are indebted for this very useful vegetable. It was introduced into Britain in 1778 by Dr Fothergill, and a good many years elapsed before it was generally cultivated as a culinary vegetable. The first to cultivate it on a large scale was the late Mr Myatt of Deptford, the well-known market-gardener. Not much more than sixty years ago he tied up five bundles of Rhubarb and sent his son to the London market with them, and so little were the Londoners inclined to purchase it that only three of the bundles could be sold. Not discouraged by his first effort to get Rhubarb into favour among such a vegetable-loving people, and believing that it would one day be highly prized, he persevered; and the next time he offered it for sale he had ten bundles, and sold them all. Since then Rhubarb has come to be so generally used that it is sent into the London markets in enormous quantities. The metropolitan market-gardeners now force thousands of roots every year, to say nothing of the supply drawn from the open ground; and this applies to almost every town in the kingdom in proportion to its population.
Almost any soil will grow Rhubarb, provided it be well manured and deeply worked. Heavy loamy soil will of course yield the longest and thickest stalks; but it is generally admitted that a drier and lighter soil gives finer-flavoured produce; so that a soil of medium character may be pronounced the best. The cultivation of this free-growing vegetable is so exceedingly simple that little detail is necessary in explaining it. In making a new plantation the ground should be heavily manured and deeply trenched in the autumn; and when planted, another dressing of manure should be dug deeply into the fresh-turned soil. It can be planted at almost any time. I have planted it when quite dormant, when commencing to grow in early spring, and when it had grown a foot high. On soils that are heavy and damp I prefer planting just as it is beginning to grow; and on dry soils it is perhaps best to plant when quite at rest.
The best mode of planting is to dig up a few well-established stools, and carefully divide them without lifting them entirely, only digging deeply on one side of each stool, and removing a few crowns with strong pieces of healthy roots attached. Planting is more tidily done as the last dressing of manure is dug into the ground, as it prevents the trampling of the ground afterwards. In ordinary cases, 4 feet each way is wide enough to plant. The crowns should not be placed deeper than the surface of the soil if it be heavy, in light soils they may be covered an inch or so with advantage, if quite dormant when planted. Where the ground is clayey, a few spadefuls of light rich soil may be put round each stool when planted.
None of the stalks should be taken from the plantation during the first year, except the flower-stalks, which should be removed as they show themselves. If the season be dry, a few liberal waterings with dung-water should be given, and the ground about mulched. The second year some of the stalks may be taken for use, but it is best to be easy with them, and if intended for forcing none should be taken from them. Indeed, the best stools for forcing are those that have made two or three years' growth without being touched. When not required for forcing, a plantation lasts for many years in a good productive state. But there are very few gardens nowadays where Rhubarb is not required for forcing, and the best way is to plant every year in proportion to the demand. Roots that have been forced are sometimes used for planting again, but it is a practice not to be recommended except in an emergency.
This is a vegetable which can be forced easily in almost any structure where a little heat can be applied. The old-fashioned way of placing pots over the crowns and filling up between and over them with fermenting materials, such as leaves or stable-manure, or both mixed, is not so much practised now as in days gone by, when good Rhubarb was so produced, though with more labour and inconvenience than by lifting the crowns and putting them in places constructed for the purpose, or in Mushroom-houses, etc, which are heated by hot water. The easiest, and in the long-run the cheapest, mode of producing early Rhubarb is to have it, as well as Seakale, in a back place near to any of the garden boilers, from whence some heat can be conveyed. A slight bed of leaves sufficient to produce a little bottom-heat is perhaps the best means of conjunction with an atmospheric warmth of 55° to 60°. The stools should be carefully dug up, the soil shaken from them, and placed close together on a thin layer of leaf-mould, spread over the surface of the leaves, and then filling in all round the roots with leaf-mould or any light rich soil.
Large quantities of Rhubarb are forced in the market-gardens round London by digging long trenches to the depth of 2 to 3 feet, and putting 2 feet of hot dung into the bottom of them, on which the roots are packed closely together in any light soil. The trenches are then hooped over and covered with about a foot depth of long stable-litter or straw, and in this rude and simple way excellent produce is the result. Others again have long ranges of wooden pits about 5 feet wide, with a hot-water pipe to supply both top and bottom heat. These are, however, giving way to larger structures, in which standing and walking room can be had.
The amateur or cottage gardener who desires forced Rhubarb, can easily produce it in a cellar or any outhouse where a few roots can be placed in a temperature of 50° to 55°. When it is required for table before the end of the year, the roots should be placed in the forcing-house as soon as the leaves commence to decay. The best sorts for early forcing are Prince Albert and Linnaeus. The Victoria yields a greater bulk late in the season, and for general crops in the open air is the most profitable. Whether Rhubarb is best when blanched by forcing or when grown in the open air, is a disputed point, and depends on taste. For my own part, I prefer it blanched, and cooked without being skinned.
A deep, rich, cool soil grows Rhubarb best; but it can be grown well in any garden soil if dug deeply, and well enriched with cow and horse manure. The best time to plant it is just when the leaves have newly dropped, although any time during winter or spring, before the buds have pushed much, will do very well. Divide the old plants into single eyes, securing as much root to each eye as possible, and plant in rows not less than 3 1/2 feet each way. Just cover the lower half of the buds in planting, and when finished give a good top-dressing of rotten dung, which will keep out frost in winter and drought in summer, and will afford nourishment to the plants besides, more especially in thin soils, as the roots will be encouraged to extend up to the top-dressing instead of down to the poor but perhaps moister subsoil. The leaves will very soon hide the dressing completely. After the first year liberal drenchings of cow-house drainage, or failing that, house sewage, will do much to give a rapid, rank growth, which is the way to produce the best Rhubarb. No stalks should be pulled the first year unless it does extremely well, when one or two may be taken from each bud about midsummer, but by no means later or it will start very weakly the following spring.
And ever afterwards this rule should be strictly followed. The return of crop from the Rhubarb plot of most villa-gardens is not worth the rent of the ground, and simply because it does not get a chance to grow. If there be any troublesome weed in the garden, the best way to weaken and eventually kill it is to treat it as many persons, who do not understand the functions of leaves, treat their Rhubarb - and that is, to pull off every leaf as fast as it makes its appearance. But if it be allowed to grow strongly and only judiciously thinned, taking care to leave two or three leaves to each bud, and not to pull wherever a suitable stalk is found, it is wonderful what an amount of Rhubarb can be taken from a very small space.
Although I could scarcely recommend the forcing of Asparagus to every amateur, I decidedly advise them to force Rhubarb, as it is so easily prepared. A good way is to put up a bed as recommended for Asparagus; and the best way to prepare plants for forcing is to make a plantation yearly on good ground, giving one season's growth without gathering from it. Grown this way, the plants are of a fine handy size, and have a great amount of matter stored up which will yield well when forced. Of course old plants will do, but the results will scarcely be so good, and old plants are difficult to handle without injury. These young plants can also be forced in the greenhouse, vinery, etc, under stages, where nothing else will grow, or even in a cellar or any place affording a temperature of 50° and upwards. The way this is generally done is to put the roots, as many as possible, into good sized pots with fine soil kept moist, but not wet, and another pot placed over it with the joint and holes made air-tight, to secure its being properly blanched.
But the commonest way is to put square boxes, with no bottoms and movable lids, or seakale covers, or large pots, over the plants as they grow in the ground, and then cover these with stable litter and leaves to the depth of 2 feet, and the same round the sides. The boxes will require to be about 20 inches square and deep for large old plants; for small plants smaller boxes will do. It can be had in this way from Christmas onwards if desired, or indeed earlier, but not many owners will care about having it earlier. In severe weather a covering of straw or mats over the prepared manure will be beneficial, indeed necessary to enable the dung to retain its heat.
In putting up secondary beds, part of the old manure can be used with the fresh; and indeed, by the end of February, a fourth part of fresh material used with the old will be enough, as little excitement will cause it to grow late in the season, and less fermenting matter will keep up the temperature. The mere pots or boxes in March will forward it considerably.