Knowledge of growing Dien pomelo

Knowledge of growing Dien pomelo, Phu Dien Ward, Hanoi City

The knowledge of growing Dien pomelo dates back hundreds of years, passed down by the people of Phu Dien Ward from generation to generation and still existing today. According to the elders, the original Dien pomelo variety was Doan Hung pomelo (Phu Tho), brought to Vang village (now Residential Groups 1, 2, 3 – Duc Dien, Phu Dien Ward, Hanoi City) for cultivation. Because it suited the soil and climate, and the people of Vang village gained suitable care experience over time, the pomelo became tastier than the original Doan Hung pomelo in Phu Tho. Later, Dien pomelo was grown in neighboring villages such as Dien village (now Residential Groups 14, 15, 16, 17, 18 – Phu Dien Ward, Hanoi City) and Van Tri village (now Van Tri Residential Groups 1, 2, 3, 4 – Tay Tuu Ward, Hanoi City).

*Selecting planting land:

The planting land is in Duc Dien village (now Residential Groups 1, 2, 3 – Duc Dien, Phu Dien Ward, Hanoi City) and surrounding areas (Dien village (now Residential Groups 14, 15, 16, 17, 18 – Phu Dien Ward, Hanoi City), Van Tri village (now Van Tri Residential Groups 1, 2, 3, 4 – Tay Tuu Ward, Hanoi City)). The soil is ancient alluvial soil deposited over a long time.

*Selecting plant varieties:

The tree selected for branch layering must be a heavy-bearing tree with large, round fruit, even segments, amber-brown juice sacs, deep sweetness, and must have been grown for at least 10 years.

*Propagation method:

The variety must be propagated by branch layering, not by seed (seed-grown trees easily degenerate or mutate). Choose a branch about 1.5 cm in diameter, then make two rings 2–3 cm apart; peel off the outer bark, scrape the inside clean, and leave it for 1–2 days.

*Soil for wrapping:

Usually, pond mud is mixed with rice husks and straw and left for a few days so that toxins such as H2S, NH4, etc. can dissipate.

*Method:

Use your hands to tear the soil mixed with rice husks and straw, then wrap it tightly around the stripped branch section (wrap it securely with pineapple-fiber sackcloth or plastic), and tie both ends tightly; the layered soil ball must be larger than an adult's fist. The best time for layering is the end of the third lunar month and the beginning of the fourth lunar month.

*Planting:

Dig the hole to place the branch one week in advance; 50 cm wide and 40 cm deep; put a little fine soil at the bottom, then remove the wrapping, place the branch so that the top of the soil ball is level with the planting soil surface; firm the soil, insert a stake to support the layered branch (prevent it from falling over), and water to keep the soil moist for the first 3–5 days.

*Care:

- Use farmyard manure, pond mud, NPK fertilizer, etc.

- Regularly cut off diseased and crooked-growing branches

- Spray pesticides and fertilize periodically

- After the tree has been planted for about 3 years (about 3 m in diameter): use a hoe to dig deep and cut the roots to stimulate new growth; then apply topdressing with composted farmyard manure and bird manure mixed with NPK, and firm the soil tightly (do this at the end of the 11th lunar month).

*Harvesting and storage:

Harvest the fruit at the end of the 11th lunar month, choose a dry, sunny day, and avoid dropping or bruising the fruit; apply lime to the stem end and keep the fruit in a cool, shaded place.

Dien pomelo brings outstanding economic efficiency thanks to its rare qualities:

- High value: Dien pomelo is a famous specialty of Hanoi, once ranked among the precious gifts presented to kings. Today, it remains a key crop that brings farmers hundreds of millions of VND per hectare per year.

- Long storage ability: An outstanding feature is that after harvesting, Dien pomelo fruit can be stored for 3–5 months while still maintaining quality; even when the peel wrinkles, the inside becomes sweeter and richer. This helps growers proactively choose the selling time, especially during Lunar New Year, to achieve the highest economic value.

- Development of deep-processed products: Recently, folk knowledge about the uses of pomelo has been applied in modern technology for deep processing to increase value:

+ Pomelo flowers: Extracted to make essential oil, tea, and cosmetics (shampoo, conditioner, makeup remover).

+ Young pomelo fruit: Extracted for essential oil and used in cosmetics because it contains a high level of bioactive compounds.

+ Pomelo peel and pith: Used as medicine (for treating flu and coughs) or in food (jam, sweet soup).

Dien pomelo is not only a fruit but also part of Vietnamese culture:

- Tet symbol: With its beautiful bright yellow color, strong fragrance, and long storage ability, Dien pomelo is one of the top choices for displaying on the five-fruit tray during Tet and for ancestor worship, representing prosperity, completeness, and good luck for the family.

- Traditional origin: Dien pomelo is associated with Duc Dien village and surrounding areas (Phu Dien village, Phu Dien Ward, Hanoi City; Van Tri village, Tay Tuu Ward, Hanoi City), carrying the long-standing historical and culinary cultural values of the people of northern Vietnam.

- Sharing experience: Pomelo-growing knowledge is passed down from generation to generation, creating community bonds in which people are willing to share experience and support each other in developing this precious pomelo variety.