This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
After the haulm has quite died back in the autumn it can be cut and burnt. Then is a good time to give a coat of well-rotted manure, thirty to forty loads to the acre, which can be forked into the beds. Where the plough is used a very light furrow may be turned from each side of the row, leaving 1 ft. between the inside of the two furrows. This will be a good way of burying any autumn weeds there may be. The manure may now be drawn on and spread up the rows. It will fall into the two furrows and on to the space left between them; this space can be forked over shallow, care being taken to insert the fork obliquely, so as not to wound the crowns; in the process the manure will be turned in on to the crowns and that lying in the furrows covered.
Before the buds are moulded up again in the spring they may be dressed with 10 cwt. agricultural salt and 2 cwt. sulphate of potash to the acre, or, as a variant, every third or fourth year, 2 cwt. of nitrate of potash to the acre. Some growers use a good deal of soot as a spring dressing; it lightens the land, and it is claimed retains more of the sun heat. If the winter dressing of manure is not given, 2 cwt. of nitrate of soda or sulphate of ammonia should be applied in the spring.
Asparagus is also grown for forcing. The procedure in this case is quite different. Probably no crop grown in market gardens requires so much money to be laid out before there is any return as does forced Asparagus. This consideration, and the other, that the demand for the product is very limited, probably account for the fact that few growers attempt it. The commencement is the same as that described above for natural Asparagus. The yearling plants, after being forked up, singled, and the weak ones thrown out, are planted in ground that has been kept well manured for several years, in rows 2 ft. apart, and 15 in. from plant to plant. They are either laid in the furrow as the land is ploughed or planted in cuts made with a spade. In either case, after planting, the ground is well firmed around them with a roller or the feet. After this there is nothing else to do but keep the crop clean during summer, and clear the old haulm away in the winter, for three years. Then the crowns are either ploughed out or dug out and laid in forcing beds heated either with hot water or manure. Boxes and lights are put over them, and fine soil is sifted to a depth of 6 to 8 in.
Fig. 458. - Bundle of Asparagus for Market.
When the buds of Asparagus come through they are gathered by forcing two fingers into the soil beside the bud and breaking it out of the crown. The buds are tied in flat bundles and washed for market. "Ware" makes 4s. to 7s. per bundle and "Sprue" 1s. to 1s. 6d. Its season is latter end of February, March, and early April. [w. g. l].
The large area of land - estimated at about 1000 ac. - devoted to Asparagus, and its average value per acre, justly entitles it to precedence over other crops of vegetables grown in the Evesham district. It is hardly too much to say that about 500 ac. have been devoted to Asparagus during the past twenty years, the period during which the writer has periodically and systematically visited all the districts in the county of Worcester in the work of the advancement of horticulture.
Asparagus is grown commercially in Worcestershire, in almost all cases, in single rows at about 3 ft. 6 in. apart; no "beds" of the private-garden type are to be seen, and double rows - which were rather plentiful upwards of sixteen years ago - are now difficult to discover. No special preparation of the soil is made, or required, for this crop. Sometimes the seed is sown where the plants are to remain; by this procedure a little time is saved. But more commonly young plants, one year old, are taken from the seed bed and planted in rows as stated, and at 18 to 24 in. apart in the rows. It is not generally known that much depends upon the care exercised in the selection of the young plants to be planted permanently; and in this respect the men of Evesham are not in advance of good Asparagus cultivators elsewhere. The seedling plant varies in character, and whatsoever its character in infancy, that it retains to maturity and senility. In other words, it is the nature of some young Asparagus plants to produce numerous but thin shoots, and they will always retain that nature no matter how cultivated. Other young Asparagus plants, from the same seed-bed, produce fewer but strong or thick shoots, and this they will do to the end of their days, other conditions being equal. Therefore, in order to have a crop of large Asparagus the main thing is to select and plant only those seedlings which produce few and strong shoots even as seedlings; but if a good average quality of asparagus be desired, then select and plant the above-mentioned and those next in strength, and producing one or two more shoots. If a mixed crop - strong and weak - of Asparagus is preferred, then plant the seedlings without any selection or separation of weak from strong.
Like all other plants, Asparagus fails in vigour after a certain time, and this depends upon circumstances. As its full vigour is generally attained at the third or fourth year after planting, it usually produces remunerative crops during the following five or six years. Then a marked loss of strength becomes apparent, new plantations are made, and the old beds "bursted up" - to use a local but expressive term - after about two or three more years. So there is a constant succession of plantations on the best-managed grounds, following each other in rotation of five or six years. The rows being planted at, say, 3 ft. 6 in. apart, other crops are taken from between the Asparagus during the first two years. These crops during the first year are Dwarf Beans, Onions, Lettuce, or Cauliflowers; during the second year they may be Lettuce or Radishes - something that is dwarf, arrives quickly at maturity, and is cleared from the ground before the "bower" of the Asparagus becomes so tall and dense as to spoil the catch crop. The third year, cutting commences in earnest, and the Asparagus pays for itself, and the ground is given up entirely to its cultivation.
The subsequent routine of culture consists in the annual manuring or feeding of the crops - which at Evesham largely consists of soot; moulding up into ridges early in spring with pulverized soil over the crowns of the plants before growth commences; covering the crowns with soil to a depth of 4 to 8 or more inches (the largest exhibition Asparagus is usually moulded or "earthed-up" to a depth of 12 in.); and the annual cutting down of the Asparagus in November, together with the levelling of the soil which had been placed over the Asparagus in spring. [J. U].
The principal enemy of the Asparagus that the grower must look out for is the Asparagus Beetle (fig. 459). The little black-and-yellow "cross-bearing " insects, as they are called from the appearance of the markings on their wing covers, can be seen on the feathery haulm when it has grown up.
The pest does damage to the buds as they come through by biting, causing them to "crook", and covering them with slime and eggs. Spraying the haulm after cutting is over with a poisonous spray, dusting the buds during cutting with slaked lime, and allowing a bud here and there to grow up as traps, to be cut off and burnt as soon as the eggs can be seen upon them, are good measures for dealing with the pest.
Fig. 459 - Asparagus Beetle (Crioceris Aspa-ragi), Larva, and Eggs (all magnified). Natural length of egg and beetle shown by lines.