The change in character and the increased usefulness of Sweet Peas have necessitated a revolution in the methods of culture.  The freer growth and more robust habit demand greater space than was formerly allowed.  Instead of crowded rows of attenuated plants, producing a meagre return of small flowers, poor in colour, it is now the practice to prepare the ground by deep trenching and liberal manuring, and to give every plant ample space for full development both in rows and in clumps.  In the ensuing paragraphs we outline the cultural routine which should be followed as nearly as possible by those who desire to insure a long-continued supply of the very finest flowers.  But where circumstances do not permit of these recommendations being adopted in full, the details may be modified according to the materials at command and the requirements of the cultivator.

It is usual to commence the preparation of the ground in autumn.  Trenching is of paramount importance, for the roots of the Sweet Pea require a considerable depth of good soil in which to ramify for the support of robust healthy plants capable of producing handsome flowers over a long season.  Where the surface soil is shallow, care must be exercised to avoid bringing uncultivated subsoil to the top, and it is well worth incurring a little extra trouble to provide a sufficient depth of fertile material for full root development.  Therefore dig out a wide trench and place the good top soil on one side.  Then remove and discard the subsoil to a depth of twelve inches and, after breaking up the bottom of the trench with a fork or pickaxe, replace with an equal quantity of decayed manure, leaves, old potting soil or any other suitable stuff that may be on hand.  Finally return the top soil to its original position.

The use of manure needs discrimination, and in fixing the quantity, as well as in selecting the most suitable kinds, due consideration must be given to the character of the soil.  For light land, four barrow-loads of well-rotted farmyard manure per square pole will make an excellent dressing, but a rather smaller amount will suffice for heavy ground.  In place of farmyard manure an unlimited quantity of leaf-soil, if obtainable, may be used, and it is also a good plan to dig in any available green refuse.  Garden ground which for some years previously has been kept in a state of high cultivation by the liberal use of natural manure will not, as a rule, need further help in this direction, but it should receive a good dressing of lime.  Indeed, any soil in which Sweet Peas are to be grown should contain not less than two per cent. of lime.  The employment of artificial, as well as organic, manures is essential in any first-class scheme of cultivation.  But here a word of warning is necessary.  Nitrogenous manures in any form are harmful to the plant when applied in large quantities, and are liable to predispose it to disease, except on extreme types of sandy soil.