THE FARM.

Pelorus Guardian and Miners' Advocate., Volume 24, Issue 20, 14 March 1913, Page 2

THE FARM.

SMALL RURAL INDUSTRIES. MINT CULTIVATION. • (By Joseph Knight, in “Vic. Journal of Agriculture.”) Mint (Menthu) includes the Pennyroyal (Mentha Pulegium), also Spearmint (Mentha viridis), which is cultivated for culinary purposes, besides other species. Our business here is with the plant commonly known as Black Mint (Mentha piperta). From this is produced the well-known Oil of Peppermint, which is largely used in medicine, confectionery, and in the manufacture of coruials. Black Mint is culti aOd largely in England and other countries for the extraction of oil, it is a hardy plant, loving a cool moist climate and a free soil. It thrives well on the hillsides in Gippsland and similar situations, is easily managed,, and gives good returns for labour bestowed on it.

The following is a brief description of its cultivation and treatment PLANTING AND CULTIVATION. The plant used to establish a ,crop consists of pieces of the stolons or runners taken from the parent plant; like most of the “Mint” tribe, it is very prolific in producing these runners. Slips with three or four joints are sufficient —they should bo well rooted, and the stronger they are the more prolific the first year’s crop will be. The runners are planted out in well prepared soil, and should stand about 15 to 18 inches apart from plant to plant each way. The land should be clean and free from weeds, as the distillation afterwards of the produce renders foreign matters undesirable. Care with the first crop will save much trouble in future working, as the plant, when once established, will, to a large extent, protect itself from any intrusion of weeds.

Fairly deep cultivation is necessary. The plant is chiefly a surface feeder, but requires some depth of soil in order to obtain the best results. The land should be well worked to a fine- tilth and smooth surface, otherwise the cutting is difficult. Little in the way of' cultivation can be done after planting, but the soil round the crop may be kept stirred with a fork, so as to give the young plant freedom in pushing out its runners for the summer cutting. In some cases, in fairly* level land and dry situations, furrows are run between the rows and water run down;, but where there is danger of '“sour,,” this must be avoided. Light forking will materially assist the plant in its development prior to cutting. The sets may be dropped in a shallow furrow and the soil turned down with a plough at the dustance decided upon, but the land must be left with a level surface for the reason stated above. The time of planting must depend largely on the parent plant, as the runners have to be taken from the season’s growth, and it is undesirable to rob it to the extent of impairing its yield for the coming harvest. In Gippsland, and other timbered localities, early in November would be time enough, in ordinary seasons. If the treatment of the soil has been suitable, there should be a fair cutting in March, and this may be treated for oil extraction straight away. The yield should then- be sufficient to meet the expenses of labour for the first year g working. After cutting the first year, the plants are, in some cases, covered up with a little loose earth, which gives them a start in making runners for producing the second crop. When the plants have been set out at a sufficient distance apart a cultivator bhould be worked between the rows. It will be found more economical to arrange this distance* and employ horse labour, than to work by hand. After the second cutting, the land may be ploughed and the plants covered, and being well established they will stand rough treatment as far as the cultivation is'concerned ; this applies to all subsequent seasons. It may be found advantageous to renew the plantation every five or six years, as new fields will be found to give better results.

HARVESTING. The time of harvesting cannot be definitely stated but the crop should be taken in full bloom. This is usually late In spring or early in autumn. The crop is usually cut with a hook, sometimes with a short-bladed scythe, frequently with a nipping machine ; it is gathered in rows, then placed on sheets of hessian, and carried direct to the still. While many allow it to dry somewhat, asserting that there is no loss of oil, but only moisture, in the evaporation, others again claim that this is a mistake. It may not al--ways be convenient to distill the whole crop in the green state ; but there is no doubt that, where this can be done, it is advisable to do so. Whatever is done, care must be taken to prevent self heating of the produce, which readily occurs if it is kept in heaps while green ; and it must not be permitted to get wet by rain and become mouldy, as the oil is affected thereby, both in quantity and quality. AFTER TREATMENT. The bulky nature of the mint crop necessitates treatment of it on or near the place at which it is produced. For this purpose, a fair-sized still is necessary—the size must be regulated by the amount of crop. A 400-gal-lon still will be sufficient for 20 acres or so. The cost of the still depends on the nature of the material employed, and other such conditions. The late Mr. Slater, of Mitcham,

Victo:ia. who was a fi-C' e t--l grow cr of plants for essential oLo.j and who , had considerable cxpcrienccJ of these in England, carried out hisj distillation work with the ordinaryf iron malt tanks —400 gallons eo/h—> which ho found to answer the purpose well. A tank was set in on bricks (roughly) in such a way as to admit of a fire being, placed underneath. The whole of the top ofthis tank was movable, and in it was fitted a cage lined with wire netting to hold the material. This, cage was let down into the tank, which was filled with water. . The lidji had a goose-necked cone to convey: the steam and oil to another tank; holding the condenser, which was ‘ simply a spiral of'tin-lined copper, piping. The lid of the first tank was made to screw down tightly on a rubber ring, in order to prevent! any escape of steam, except through; the condenser. The second tank was: o)en, and contained the condenser only ;. and as a steam of water not available to run into this, a third tank was employed 'to supply, a current of cold water to keep the condenser cool. A steady stream of water was delivered to the bottom of the condensing tank, which, of course, as it heated, rose to the top and found its way to the overflow. These simple and inexpensive appliances answered the purpose, but where a more elaborate outfit is de-, sired, many of our coppersmiths can supply it. Messrs. Dondey, and Testro. South Melbourne, have a very, convenient still, made of the latest!, pattern, and no doubt will be rea- . sonabla in their charges. Their experience in still-rnaking should be’ a warranty that a suitable article will be supplied. The treatment of the various plants* from which the oil is extracted by, distillation is carried out in the same manner as the product now under consideration. There is one thing very necessary when changing from one product to another—a thorough deodorizing and cleaning must take place, otherwise much of the product will he destroyed. DISTILLING. 1

This operation is looked up> n as being somewhat difficult, but it only requires a little practice to get good results. It may be mastered by the most inexperienced person with p, few trials.

The oil contained in the leaves and stems is lighter than water, and it has also a lower boiling point. When heat is applied the oil rises and passes off with a little steam before the boiling point of the water is reached. The finer and better part of the oil escapes first, and here it is that care and skill is required to make the most of the product, and to secure a first and second quality of oil. The steam, water, and oil which passes through the condenser referred to, passes out through the lower portion of the cooling tank into a receiver known as the "Florentine.” This somewhat resembles a teapot without a handle. The oil and water dropping into the top of the receiver separate, the oil floating on the top whilst the water escapes slowly at the Spoilt. As the outlet is at the bottom of this receiver and the top of the spout a Utile below the mouth or level of the receiving poi’tion of the "‘Florentine,” the water and oil are separated. One mistake frequently made is in forcing the distillation. The boiling should be slow, so as to avoid over objectionable matter. A tank of 400 gallons should be allowed four or five hoxxrs to boil ; after the first two hours the receiver should be changed, as the oil to follow is of aeccniary quality, and should be marketed separately. It is said that whatever oil the stalks contain is inferior in quality, and,, being the last to.be driven off, the heat must be regulated and the boiling a simmer only. In distilling, it is much preferable to heat the water in the boiling tank with supeiheated steam, as it is more under control. This is done by having a steam generator close by, and running steam .through a perforated coil placed in the bottom of the stall. The heat can then be regulated to a nicety. Some eucalyptus distillers run hot steam tlxrough their leaves without water, but this does not meet with general approval for the finer essential oil plants. When applying direct heat greater attention is required than in using steam. YIELDS AND PRICES. !

A good crop of well-established mint will yield from five to six' tons per imperial acre. As to the yield of oil, some growers give 3 to 4 lbs. per ton, whilst .others statei 5 to 6 lbs. ; nothing definite can bo given in this respect. At the Dunoily and Leogatha Government Scent Farm mint was the last crop to receive attention, and it was uotl. sufficiently established to give any reliable data to quote from.