The pomelo plant is a small tree 5-15 m tall, low-branching; spiny if propagated from seed or spineless if propagated vegetatively. Trees grown from seed are usually tall and slender and start bearing fruits 6-8 years after sowing.
Soil and Climate Adaption
The pummelo thrives in the lowland tropics. For commercial production, elevation not exceeding 400 masl is preferred with optimum temperature of 25-30 c. It can tolerate a wide range of soils from course sand to heavy clay. However, it prefers deep, medium-textured, fertile soils free from injurious salts; optimum pH from 5.5 to 6.5; annual rainfall requirement 1500-1800 mm. In the 3 major pummelo provinces of Thailand, the best orchards are situated on the banks of current and former courses.
Plant Propagation
Pummelo can be propagated sexually by seed or asexually by air layering (marcotting), budding, grafting and stem cuttings.
Land Preparation and Planting
In sloping lands and in staggered planting, the farm can be prepared by slashing of the vegetation and clearing of the immediate peripheries of the hills. Otherwise, the land should be prepared thoroughly by plowing and harrowing. If the soil is too acidic, lime should be applied. Holes or pits are then dug about 0.5 m deep and wide.
The plant-to-plant spacing is 8-10 m x 6-8 m, depending on the terrain and soil fertility. This is equivalent to a population density ranging from about 125 to 208 plants per hectare. To ensure supply of nutrients, compost is applied at the bottom of the hole or mixed at about 1/3 proportion with the topsoil which will be used to refill the hole after planting. In general, planting is delayed for at least 15 days if raw manure will be used
Watering
Watering should be done immediately after planting to ensure contact of the soil and roots and to prevent wilting. The regular supply of water is especially important before flowering and until after harvest. To force early flowering, irrigation is delayed during the dry season until the trees show signs of wilting. The wilting trees are the irrigated. To sustain new shoot growth and the development of flowers and fruits, regular supply of water is needed. A manure pummelo tree may need 100 - 200 li water daily during dry periods.
Weeding
Pummelo needs regular weeding to eliminate competition for soil moisture and nutrients. The uprooted weeds can be piled around the base of the trees to serve as mulch
Pruning
At 4-6 months after planting, the trees are pruned to induce branching. This is done by top pruning about 30-40 cm from ground . 3 branches which are evenly distributed in separate horizontal directions are retained and allowed to develop.
Fertilizing
Proper fertilization is a standard cultural practice in fruit production, especially in association with floral induction. Apply 5 kg complete fertilizer per tree per year split into 6 applications or every two months. Foliar fertilizer is also applied every new flushes. In other parts of the country, 2-split applications are recommended, the first before flowering and the second 4-6 months later
In the Philippines, the recommended rate of fertilizer per year increases from 5-20 kg organic. The fertilizer is applied in holes about 1-2 meters from the trunk. Spraying of foliar fertilizer is likewise recommended every 20-day interval starting at 40 until 140 days after fruit set
Pests and diseases
All pests of citrus also attack the pummelo plant. These include the common leafminers, leaf-eating caterpillars, fruit-boring caterpillar, scales, red mites, fruits flies, nematodes and rats.
Harvesting
The pummelos are picked at maturity which occurs about 140-160 days from fruit set. The dull skin of the fruit brightens upon ripening as the oil glands become more prominent and shiny. This change starts near the tip of the fruit and progresses towards the stalk.
At 4-6 months after planting, the trees are pruned to induce branching. This is done by top pruning about 30-40 cm from the ground. 3 branches which are evenly distributed in separate horizontal directions are retained and allowed to develop.
At 4-6 months after planting, the trees are pruned to induce branching. This is done by top pruning about 30-40 cm from the ground. 3 branches which are evenly distributed in separate horizontal directions are retained and allowed to develop
