Budded Orange Seedlings
The most common method of citrus propagation is by budding via bark grafting of old trees. Citrus varieties grown from seed have numerous problems like late bearing, an uneven performance due to their genetic variability and susceptibility to drought, root invading fungi, nematodes and salinity.
Growing and Transplanting Citrus Seedlings:
- Orange trees like a pH between 6 and 7.0 in citrus-specific potting soils (light, well-drained sandy soils are most ideal.
- For good production oranges require well-distributed rainfall or supplementary irrigation throughout the year. A good source of water is therefore essential in orange farming.
- Spacing varies widely, depending on elevation, rootstock and variety. Generally, trees need a wider spacing at sea level than those transplanted at higher altitudes. Usually the plant density varies from 150 to 500 trees per ha, which means distances of 5 x 6 m or 7 x 8 m (oranges, grapefruits).
- It is very important to ensure that seedlings are not transplanted too deep.
- After planting, the seedlings ought to be at the same height or preferably, somewhat higher than in the nursery (Maintain a single stem up to a height of 80-100 cm).
- Under no circumstances must the graft union ever be in contact with the soil or with mulching material if used.
- Pinch or break the top branch at a height of 100 cm to encourage side branching.
- Allow 3-4 scaffold branches to form the framework of the tree.
- Ensure all diseased and dead branches are removed regularly.
- Careful use of hand tools is necessary in order to avoid injuring tree trunks and roots. Such injuries may become entry points for diseases.
- As a general rule, if dry spells last longer than 3 months, irrigation is necessary to maintain high yields and fruit quality.
- Extremely hot temperatures are damaging to citrus. Ideal temperatures range from 13 °C to 38 °C. At higher temperatures, flowers and leaves drop prematurely.
- Rainfall or irrigation throughout most of the year is necessary for citrus, however, dry and hot temperatures during the day and cool temperatures at night are favourable conditions for good colour development.
- Adequate drainage is also needed, as tree growth is reduced in poorly drained soils or where compacted soil layers are present in the root zone.
- Furthermore, poor drainage causes problems with Phytophthora and other soil-borne diseases.