Home garden design > Fruit growing > Citrus fruit > Orange tree growing

Orange tree growing

Orange tree growingThe orange is king of the citrus fruits. It may be treated as a type representing the other members of the group in many particulars relating to soils and cultural methods. In some respects special treatment is required for lemons, limes, and pomelos, as described in the sections devoted to these fruits.

Orange tree climate - In general it may be stated that in all regions in which the temperature does not fall below 18 degrees Celsius above zero nor rise above 100 degrees Fahrenheit, and where there is sufficient moisture, citrus fruits may be produced. There are, however, localities within these limitations that can not be said to be good citrus-growing sections. In some places, although the trees grow luxuriantly, heavy rainfalls occur at the time when the fruits are maturing, making it hard to gather. In others the conditions for vegetative growth are so favorable that very little fruit sets. Regions that are excessively dry may, however, be utilized for citrus culture when irrigation can be practiced. The more nearly the northern limit of the citrus belt is approached, the more sprightly and deliciously flavored the fruit becomes, some of the very best fruit being grown from areas where the trees every winter are in danger of being frozen out.

The ideal climate for citrus growing is one in which the rainĀ­fall occurs after the fruit has been harvested and before the new crop begins to ripen. The rainfall should not be excessive, certainly not more than 50 to 70 inches annually, and the winter temperature should not go below 26 to 27 degrees Fahrenheit of continued cold, though a lower temperature may be withstood for an hour or more without killing the trees. Orange trees in a thoroughly dormant condition can withstand a temperature as low as 24 degrees Fahrenheit if this is not continued for more than a few hours at a time. A very sharp turn to 18 degrees, if for only a few hours; will entirely defoliate trees in the most dormant condition, while it is likely to kill the larger proportion of those in active growth. Small trees under 8 to 10 feet high, with poorly protected trunks, are very apt to be cut to the ground under these conditions. Sometimes snow falls and remains on the trees for some hours without seriously damaging orange trees; but this is of rare occurrence.

Orange tree soil - The orange will grow successfully in a great variety of soils, yet there are a few essential characteristics of a good orange soil which can not be overlooked with safety by the prospective grower. The soil must be abundantly moist but must allow good drainage. It should be deep and rich. It is best to avoid the extremes, of heavy and loose texture, though some very heavy soils have given excellent results, particularly when overlaid by a stratum of lighter character. Shallow soils and those underlaid with hard pan near the surface are unsuited to orange culture.

Orange tree seeds - The easiest method of propagation is by seed, but this plan is unsatisfactory when used alone. The seeds of these, as of many other plants, can not be relied upon to reproduce the variety from which they are taken, and for this and other reasons the seedling orange has ceased to be desirable as a commercial fruit. Almost any seedling sweet orange, given proper care and cultivations, will produce fruit that is edible, but seedlings have no uniformity as to size, thickness of rind, flavor, number of seeds, or other essential characteristics. Occasionally a tree is found producing fruit which combines the elements of a good merchantable orange, but such cases are rare. Seed propagation must, for the reasons given above, be supplemented by budding and grafting.

In growing the seedling trees which are to be budded the seeds may be started in an open seedbed, or in deep boxes. In any case the soil should be well drained and friable and should be made fairly fich, preferably by the use of commercial fertilizers, applied two or three weeks before planting. The seeds should be planted while fresh and should not be allowed to dry out. If it is desired to hold them for some time before planting they may be preserved by burying deeply in moist sand. If large numbers of seeds are desired the fruits may be allowed to decay and the seeds washed out later through a sieve. The seed may be planted not more than 1 inch deep, in rows 3 or 4 inches apart, or wider if it is desired to keep them clean with the hoe. They will not germinate for about six weeks. When they have made a growth of about 6 inches they may be removed and placed in nursery rows, where the soil has been well prepared and fertilized. In the nursery the plants may stand 12 to 18 inches apart, in rows 4 to 6 feet apart. Keep the ground well tilled, moist, and rich enough to produce a vigorous, steady growth. At about two years from seed the young trees will be large enough to bud, and a year or two later may be dug up and set out in the orchard or grove.

Another method of propagation, which is often very convenient for use in the home garden, is that known as "air layering," or
"Chinese layering." This consists in removing a ring of bark from one of the branches, or partly severing it, and surrounding the wound with moist soil until roots are formed. For this purpose select a branch conveniently located and about 1.5 inches in diameter. Remove a ring of bark about as wide as the diameter of the branch. Surround about 7 or 8 inches of the branch at the girdled point with soil, held in place by being bound around with sacking or by a box which has been previously constructed for the purpose with openings on the sides to admit the branch. The soil must be kept constantly moist. When the roots have formed and filled the soil cut back the top, cut off the branch below the ball of soil and plant it, without removing the wrapping, if the latter be sacking or any material which will decay rapidly in the soil.

It is much simpler to practice ordinary layering by bending one of the lower branches to the ground, where possible, but most of the orange and other citrus trees are headed so high that this would be impracticable. The only advantage of any method of layering is that a few bearing trees may be produced more rapidly than by planting the seed and awaiting its growth for budding.

Orange tree planting - This must be done with care. If its roots have not been balled and sacked, some will be more or less dried and some may have been bruised. These should be cut back to sound and living wood before the tree is set out. Placing good surface soil in the bottom of the hole, set the tree upon it and spread out the roots so that they will occupy their natural position as nearly may be possible. The tree must not stand deeper in the soil than it did in the nursery. Many trees are killed or stunted by being planted too deep. Fill in the soil gradually and press it about the roots, but not too tightly, unless it be a very light soil. If water is available, it is well to settle the soil about the roots by its use, but in this case, tramping must not be done on the wet soil.

Pruning the Orange tree - Cutting back is necessary, unless the tree has been removed with a large ball of earth. It has lost a large part of its root system in bein moved and can not support the whole top. This pruning may be done either before or after planting. The main stem or leader of the tree should be cut back to a bud or branch, about 2.5 feet to 3 feet from the ground and the side branches should all be cut back, more or less severely, according to the injury which has been sustained by the root system.

All citrus trees require liberal amounts of water. The exact quantity necesary can not be stated, since it will vary with the character of the soil, the distribution of the rainfall, and the care taken in its conservation in the soil. In California it may be said in general to vary from 24 to 44 inches in depth per year, including precipitation and irrigation, but it is carefully applied and conserved so as to make the very best use of it. These figures must be regarded not as a prescription, but simply as a standard of measurement for varying conditions.