Trenching is one of the readiest modes in the gardener's power for renovating his soil. The process is thus conducted: -

"From the end of the piece of ground where it is intended to begin, take out a trench two spades deep, and twenty inches wide, and wheel the earth to the opposite end to fill up and finish the last ridge. Measure off the width of another trench, then stretch the line and mark it out with the spade. Proceed in this way until the whole of the ridges are outlined, after which begin at one end and fill up the bottom of the first trench with the surface or 'top spit' of the second one; then take the bottom * spit' of the latter, and throw it in such a way over the other as to form an elevated sharp-pointed ridge. By this means a portion of fresh soil is annually brought on the surface to the place of that which the crop of the past season may have in some measure exhausted." - Gard. Chron.

Bastard-Trenching is thus performed: -

"Open a trench two feet and a half or a yard wide, one full spit, and the shoveling deep, and wheel the soil from it to where it is intended to finish the piece, then put in the dung and dig it in with the bottom spit in the trench, then fill up this trench with the top spit, etc, of the second, treating it in like manner, and so on. The advantages of this plan of working the soil are, the good soil is retained at top, an important consideration where the subsoil is poor or bad, the bottom soil is enriched and loosened for the penetration and nourishment of the roots, and allowing them to descend deeper, they are not so liable to suffer from drought in summer; strong soil is rendered capable of absorbing more moisture, and yet remains drier at the surface by the water passing down more rapidly to the subsoil, and it ensures a thorough shifting of the soil." - Gard. Chron.

In all trenching, whether one, two, or more spades deep, always, previous to digging, put the top of each trench two or three inches deep or more, with all weeds and other litter at the bottom of the open one, which not only makes clean digging, and increases the depth of loose soil, but all weeds and their seeds are regularly buried at such a depth, that the weeds themselves will rot, and their seeds cannot vegetate.