Of the four methods of propagating plants
XXXIX. The second operation, namely that of propagating, must be considered in relation to the proper time for sowing each kind of seed, for this concerns the aspect of the field you are to sow and the season fitting for what you are to plant. Do we not see some things grow best in the spring, others in summer, some in autumn, and others again in winter? For each plant is sowed or propagated or harvested in season according to its nature: so while most trees are grafted most successfully in spring, rather than the autumn, yet figs may be grafted at the summer solstice, and cherries even in winter.
And since there are four methods of propagation of plants, by nature and by the several processes of art, namely: transplanting from one place to another, as is done in layering vines, what is called cuttage or propagating quick sets cut from trees, and graftage, which consists in transferring scions from one tree to another, let us consider at what season and in what locality you should do each of these things.
a. Seeding, and here of seed selection
XL. In the first place, the seed, which is the principle of all germination, is of two kinds, that which is not appreciable by our senses and that which is. Seed is hidden from us when it is disseminated in the air, as the physicist Anaxagoras holds, or is distributed over the land by the surface water, as Theophrastus maintains. The seeds which the farmer can see should be studied with the greatest care. There are some varieties, like that of the cypress, which are so small as to be almost invisible, for those nuts which the cypress bears, that look like little balls covered with bark, are not the seed but contain it. Nature gave the principle of germination to seed, the rest of agriculture was left for the experience of man to discover, for in the beginning before the interference of man plants were generated before they were sown, afterwards those seeds which were collected by man from the original plants did not generate until after they had been sown.
Seed should be examined to ascertain that it is not sterile by age, that it is clean, particularly that it is not adulterated with other varieties of similar appearances: for age has such effect upon seed as in some respects to change its very nature, thus it is said that rape will grow from old cabbage seed, and vice versa.49
b. Transplanting
In respect of transplanting, care should be taken that it is done neither too soon nor too late. The fit time, according to Theophrastus, is spring and autumn and midsummer, but the same rule will not apply in all places and to all kinds of plants: for in dry and thin clay soil, which has little natural moisture, the wet spring is the time, but in a rich and fat soil it is safe to transplant in autumn. Some limit the practice of transplanting to a period of thirty days.
c. Cuttage
In respect of cuttage, which consists in planting in the ground a live cutting from a tree, it behooves you especially to see that this is done at the proper time, which is before the tree has begun to bud or bloom: that you take off the cutting carefully rather than break it from the parent tree, because the cutting will be more firmly established in proportion as it has a broad footing which can readily put out roots: and that it is planted promptly before the sap dries out of it.
In propagating olives select a truncheon of new grown wood about a foot in length and the same size at each end: some call these clavolae and others call them taleae.
d. Graftage
In respect of graftage, which consists in transferring growing wood from one tree to another, care must be taken in selecting the tree from which the scion is taken, the tree on which it is grafted, and the time and the manner in which it is done: for the pear cannot be grafted on an oak, even though it may upon the apple. In this operation many men who have great faith in the sayings of the soothsayers give heed to their warning that as many kinds of grafts there may be on a tree so many bolts of lightning will strike it, because a bolt of lightning is generated by each graft (ictu).50
If you graft a cultivated pear upon a wild pear tree no matter how good it may be, the result will not be as fortunate as if you had grafted on another cultivated pear. Having regard for the result, on what ever kind of tree you graft, if it is of exactly the same kind, as, for instance, apple on apple, you should take care that the scion comes from a better tree than that on which it is grafted.
e. A “new” method — inarching
There is another operation recently suggested,51 for propagating one tree from another, when the trees are neighbours. From the tree from which you wish to take a scion a branch is trained to that on which you wish to make the graft and the scion is bound upon an incision in a branch of the stock. The place of contact of both scion and stock is cut away with a knife so that the bark of one joins evenly with the bark of the other at the point of exposure to the weather. Care should be taken that the growing top of the scion is pointed straight upwards. The following year when the graft has knitted, the scion may be cut from its parent tree.
Of when to use these different methods
XLI. The most important consideration in propagating is, however, the time at which you do it: thus things which formerly were propagated in the spring now are propagated in summer, like the fig, whose wood is not heavy and so craves heat, as a consequence of which quality figs cannot be grown in cold climates. For the same reason water is dangerous to a new fig graft because its soft wood rots easily. For these reasons it is now considered that midsummer is the best season to propagate figs. On the other hand it is the custom to tie a pot of water above a graft of hard wood trees so that it may drip on the graft and prevent the scion from drying up before it has been incorporated with the stock. Care must be taken that the bark of the scion is kept intact, and to that end it should be sharpened but so that the pith (medulla) is not exposed. To prevent the rain or the heat from injuring it from without, it should be smeared with clay and bound with bark. It is customary to take off the scion of a vine three days before it is to be grafted so that the superfluity of moisture may drain out before the scion is inserted, or, if the graft is already in place, an incision is made in the stock a little below the graft from which the adventitious moisture may drain off: but this is not done with figs and pomegranates, for in all trees of a comparatively dry nature the graft is made immediately. Indeed, some trees, like the fig, are best grafted when the scion is in bud.
Of the four kinds of propagation which I have discussed, that of graftage is preferred in respect of those trees which, like the fig, are slow in developing: for the natural seeds of the fig are those grains seen in the fruit we eat and are so small as scarcely to be capable of sprouting the slenderest shoots. For all seeds which are small and hard are slow in germinating, while those which are soft are more spontaneous, just as girls grow faster than boys. Thus by reason of their feminine tenderness the fig, the pomegranate and the vine are quicker to mature than the palm, the cypress and the olive, which are rather dry than humid by nature. Wherefore we some times propagate figs in nurseries from cuttings rather than attempt to raise them from seed: unless there is no other way to secure them, as happens when one wishes to send or receive seed across the sea. For this purpose the ripe figs which we eat are strung together and when they have dried out are packed and shipped wheresoever we wish, and thereafter being planted in a nursery they germinate. In this way the Chian, the Chalcidian, the Lydian, the African and other foreign varieties of figs were imported into Italy.
For the same reason olives are usually propagated in nurseries from truncheons such as I have described, rather than from its seed, which is hard like a nut and slow to germinate.
Of seeding alfalfa
XLII. You should take care not to plant alfalfa52 in soil which is either too dry or half wet,53 but in good order. The authorities say that if the soil is in proper condition a modius (peck) and a half of alfalfa seed will suffice to sow a jugerum of land. This seed is sowed broad-cast on the land like grass and grain.
Of seeding clover and cabbage
XLIII. Snail clover (cytisus) and cabbage is sowed in beds well prepared and is transplanted from them and set out so that the plants are a foot and a half apart, also cuttings are taken from the stronger plants and set out like those which were raised from seed.
Of seeding grain
XLIV. The quantity of seed required for one jugerum is, of beans, four modii, of wheat five modii, of barley six modii, and of spelt ten modii: in some places a little more or a little less; if the soil is rich, more; if it is thin, less. Wherefore you should observe how much it is the custom to sow in your locality in order that you may do what the region and the quality of the soil demands, which is the more necessary as the same amount of seed will yield in some localities ten for one, and in others fifteen for one, as in Etruria. In Italy also, in the region of Sybaris it is said that seed yields as much as one hundred for one, and as much is claimed for the soil of Syria at Gadara, and in Africa at Byzacium.54
It is also important to consider whether you will sow in land which is cropped every year which we call restibilis, or in fallow land (vervactum), which is [ploughed in the spring and so] allowed an interval of rest.”
“In Olynthia,” said Agrius, “they are said to crop the land every year but to get a greater yield every third year.”
“A field ought to lie fallow every other year,” said Stolo, “or at least be planted with some crop which makes less demand upon the soil.”