Temperatures at every point are of great importance. The bed should be near 80° when the spawn is inserted. The air temperature requisite to the rising crop is 60° to 65°, which is the usual temperature of the season when Mushrooms appear in pastures. While the bed is bearing a temperature of 55° will suffice, but at any point below this minimum production will be slow and may come to a stop. When giving water, take care that it is at a temperature rather above than below that of the bed.
MUSTARD
Sinapis alba, and S. nigra
Mustard is much valued as a pungent salad, and for mixing in the bowl it may take the place of Water Cress when the latter is not at command. Mustard is often sown with Cress, but it is bad practice, for the two plants do not grow at the same pace, and there is nothing gained by mixing them. The proper sort for salading is the common White Mustard, but Brown Mustard may be used for the purpose. Rape is employed for market work, but should be shunned in the garden. As the crop is cut in the seed leaf, it is necessary to sow often, but the frequency must be regulated by the demand. Supplies may be kept up through the winter by sowing in shallow boxes, which can be put into vineries, forcing pits, and other odd places. Boxes answer admirably, as they can be placed on the pipes if needful; they favour the complete cutting of a crop without remainders, and this is of importance in the case of a salad that runs out of use quickly and is so easily produced. From Lady Day to Michaelmas Mustard may be sown on the open border with other saladings, but as the summer advances a shady place must be found for it.
ONION
Allium Cepa
The onion has the good fortune to be generally appreciated and well grown almost everywhere. It enhances the flavour and digestibility of many important articles of food that would fail to nourish us without its aid, while to others it adds a zest that contributes alike to enjoyment and health. Although there are but few difficulties to be encountered in the cultivation of the Onion, there is a marked difference between a well-grown crop and one under poor management. There is, moreover, what may be termed a fine art department in Onion culture, one result being special exhibitions, in which handsome bulbs of great weight are brought forward in competition for the amusement and edification of the sight-seeing public. Thus, when the first principles have been mastered, there may be, for the earnest cultivator of this useful root, many more things to be learned, and that may be worth learning, alike for their interest and utility.
Treatment of Soil.—The Onion can be grown on any kind of soil, but poor land must be assisted by liberal manuring. A soil that will not produce large Onions may produce small ones, and the smallest are acceptable when no others are to be had. But for handsome bulbs and a heavy crop a deep rich loam of a somewhat light texture is required, although an adhesive loam, or even a clay, may be improved for the purpose; while on a sandy soil excellent results may be obtained by good management, especially in a wet season. In any case the soil must be well prepared by deep digging, breaking the lumps, and laying up in ridges to be disintegrated by the weather, and if needful its texture should be amended, as far as possible, at the same time. A coat of clay may be spread over a piece of sand, to be thoroughly incorporated with it; on the other hand, where the staple is clay, the addition of sand will be advantageous. All such corrective measures yield an adequate return if prudently carried out, because it is possible to grow Onions from year to year on the same ground; and thus in places where the soil is decidedly unsuitable a plot may be specially prepared for Onions, and if the first crop does not fully pay the cost, those that follow will do so. But the plant is not fastidious, and it is easy work almost anywhere to grow useful Onions. The first step in preparing land is to make it loose and fine throughout, and as far as possible to do this some time before the seed is sown. For sowing in spring, the beds should be prepared in the rough before winter, and when the time comes for levelling down and finishing, the top crust will be found well pulverised, and in a kindly state to receive the seed. Stagnant moisture is deadly to Onions, therefore swampy ground is most unfit; but a sufficient degree of dryness for a summer crop may often be secured by trenching, and leaving rather deep alleys between the beds to carry off surface water during heavy rains.
Manures.—As almost any soil will suit the Onion, so also will almost any kind of manure, provided that it be not rank or offensive. This strongly flavoured plant likes good but sweet living, and it is sheer folly to load the ground for it with coarse and stimulating manures. Yet it is often done, and the result is a stiff-necked generation of bulbs that refuse to ripen, or there may be complete failure of the crop through disease or plethora. But any fertiliser that is at hand, whether from the pigstye, or the sweepings of poultry yards or pigeon lofts, may be turned to account by the simple process of first making it into a compost with fresh soil, and then digging it in some time in advance of the season for sowing, and in reasonable but not excessive quantity. All such aids to plant growth as guano, charcoal, and well-rotted farmyard manure, may be used advantageously for the Onion crop; but there are two materials of especial value, and costing least of any, that are universally employed by large growers, both to help the growth and prevent maggot and canker. These are lime and soot, which are sown together when the ground is finally prepared for the seed, and in quantity only sufficient to colour the ground. They exercise a magical influence, and those who make money by growing Onions take care to employ them as a necessary part of their business routine.
Spring-sown Onions require to be put on rich, mellow ground, the top spit of which is of a somewhat fine texture, and at the time of sowing almost dry. Having been well dug and manured in good time, the top spit only should be dug over when it is finally made ready for the seed. The work must be done with care, and the beds should be marked off in breadths of four feet, with one-foot alleys between. Break all lumps with the spade, and work the surface to a regular and finely crumbled texture. Light soil should be trodden over to consolidate it, and then the surface may be carefully touched with the rake to prepare it for the seed. March and April are the usual months for spring sowing, although in mild districts seed is sometimes put in as early as January. Space the rows from nine to twelve inches apart, according to the character of the sort and the size of bulbs required. The drills must be drawn across the bed, at right angles to the alleys, for when drawn the other way it is difficult to keep the ground properly weeded. For a crop of Onions intended for storing, the seed should be only just covered with fine earth taken from the alleys and thrown over, after which the drills must be lightly trodden, the surface again touched over with the rake, and if the soil is dry and works nicely, the business may be finished by gently patting the bed all over with the back of the spade. If the ground is damp or heavy, this final touch may be omitted, as the Onion makes a weak grass that cannot easily push through earth that is caked over it. But speaking generally, an Onion bed newly sown should be quite smooth as if finished with a roller. To the beginner this will appear a protracted and complicated story, but the expert will attest that Onions require and will abundantly pay for special management.