Tapping into seaweed 'gold mine': Secret to delicious, crunchy, and clean sea grapes

A meticulous process and "golden" experience of farmers

To produce sea grape bunches that are crunchy, sweet, odor-free, and meet export standards, farmers in Dong Ninh Hoa ward, Khanh Hoa province, must follow a strict technical process that requires caution right from the beginning.

Bài liên quan

Tapping into seaweed 'gold mine': A new path to increase livelihood

According to local farmers, former shrimp and sweet snail ponds are first dredged to remove thick mud layers, then sun-dried for about a week to sterilize them. The pond banks are reinforced to prevent water leakage. Seawater is sourced from clean areas with suitable salinity levels and filtered through a sedimentation system before being pumped into the ponds.

Mr. Nguyen Thanh Minh, a sea grape farmer in Dong Ninh Hoa ward, shared, "The ideal conditions for sea grapes to grow and develop well are warm waters with temperatures of 25-28°C and salinity levels of 30-35‰. Therefore, each sea grape-farming pond is covered with sunshade nets to regulate water temperature. At the same time, the seawater used for sea grape farming must be regularly checked and renewed to maintain proper salinity."

Furthermore, based on the experience of local sea grape farmers, after each harvest, the pond bottoms are rehabilitated to enhance humus content and supplemented with nutrients such as decomposed manure and fish remains to improve the quality of subsequent crops. Moreover, during rainy periods, sea grape-farming ponds are used to circulate water, similar to shrimp farming, to prevent effects on sea grapes.

Regarding farming techniques, farmers currently use the bottom-planting method, which involves attaching sea grape branches to bamboo or wooden stakes and fixing them to the pond bottom. The branches are spaced about 40 x 40 cm apart, with a planting density of approximately 200 kg of seeds/sao (roughly 1,000 m²).

In addition to the traditional bottom-planting method, Tri Tin Co., Ltd. has also adopted a tray-planting technique, in which sea grapes are grown in square trays measuring 1 m², suspended about 30 cm above the pond bottom. The ponds are also covered with shade nets for protection and temperature regulation.

According to a representative of Tri Tin Co., Ltd., this farming method produces yields of 50–60 tons/ha, doubling that of traditional methods used by local farmers. The company is currently conducting further research to increase productivity to around 100 tons/ha, after which the model will be shared with households partnering with the enterprise in sea grape farming.

At present, the technical process for sea grape farming in Dong Ninh Hoa ward follows a biosecurity approach that minimizes the use of chemicals, ensuring that the final products meet food safety standards.

Stable yield and profit

One of the advantages of sea grapes is that they can be harvested for several years after a single planting. In terms of the growth cycle, it takes about one month for the sea grapes to establish and grow steadily after seeding. Afterward, farmers can harvest regularly every 15 days, with the farming season lasting approximately 7-8 months each year.

Mr. Tran Van Hoan, a sea grape farmer in the Dong Ha residential area, shared that each harvest takes place every 15-30 days. Sea grapes grow most vigorously from February to October each year, while growth slows during the rainy and cold months.

Each year, Mr. Hoan supplies dozens of tons of sea grapes meeting quality standards, such as branches at least 6 cm long, with thick, green beads and dense clusters, to enterprises. Regarding productivity, farmer Nguyen Thanh Minh noted that on average, one sao can yield around 400 kg/harvest. The price of type-1 fresh sea grapes ranges from VND 35,000 to 40,000/kg in the summer and can reach up to VND 60,000/kg at peak times. After deducting costs, farmers earn profits of VND 400–500 million/ha.

Another key advantage of sea grapes grown in Dong Ninh Hoa ward lies in the region's natural conditions. The local seawater is clean, with suitable salinity and rich mineral content, giving the sea grapes their vibrant green color, crisp texture, and natural sweetness. Thus, Dong Ninh Hoa sea grapes are highly favored in the market.

* USD 1 = VND 26,097 (Source: Vietcombank)