How to Grow Taro? Detailed Explanation of Planting Methods and Key Technical Points

Taro is a perennial tuberous plant, often cultivated as an annual crop. The leaves are shield-shaped, and the petioles are long and stout, green or purplish-red; the base of the plant forms a shortened stem that gradually accumulates nutrients and enlarges into a fleshy corm, called “taro” or “mother taro,” which may be spherical, ovate, elliptical, or block-shaped. Each node of the mother taro has a bud, but the axillary buds at the middle and lower nodes are the most active, producing the first tiller and forming a small corm called a “daughter taro”; from the daughter taro, “granddaughter taros” are then produced, and under suitable conditions, great-granddaughter or great-great-granddaughter taros can also form. It likes high temperatures and moisture, is not drought-tolerant, is relatively shade-tolerant, and has the characteristics of an aquatic plant, so it can be cultivated in either paddy fields or dry land. Its root system has weak absorption capacity, and it requires sufficient water throughout the growing period; it has wide adaptability to soil, with fertile, deep clayey soil with strong water retention being most suitable; seed taros begin to sprout at 13-15°C, the optimum growing temperature is above 20°C, corms form under short-day conditions, and the optimum temperature for development is 27-30°C. If exposed to low temperatures and drought, growth is poor, seriously affecting yield.

① Germination stage. The optimum germination temperature for taro is 13-15°C, and multi-corm taros can germinate normally at 12-13°C. When the suitable season arrives, sowing must be done in time, neither too early nor too late. In southern China, planting should be done in February; in the Yangtze and Yellow River basins, planting should be done in early to mid-March; in North China, planting should be done from mid-to-late March to early April; in the cold regions of Northeast China, apart from selecting early-maturing varieties, the planting period can be scheduled for May. If cultivated under protection, planting can be advanced by 5-15 days according to local climatic conditions.

In areas with a relatively short frost-free period, open-field cultivation cannot meet the growth period of taro, so artificial protection methods can be used for seedling raising, setting up cold frames, hotbeds, or greenhouse seedlings, with dense rows in the bed for sprouting, and the temperature should be maintained at about 20°C; when the sprouts are 4-5 cm long, the seedlings can be lifted and planted.

② Seedling stage. As the farming proverb says, “Seeing seedlings brings three parts joy; a full stand gives half the harvest.” This shows that a full and vigorous stand is the foundation of a good harvest. This stage generally begins when the first leaf starts to spread flat and ends when the fourth leaf spreads flat. In the south, this is already early April; in the Yangtze and Yellow River basins, late April; in North China, mid-to-late May; in Northeast China, late June to mid-June. During this period, the main tasks are to raise soil temperature, promote increased root growth and elongation, frequently hoe and weed, water less, and control seedling growth so the plants become sturdy, laying a foundation for the vigorous growth stage; the most suitable temperature for taro growth during this period is 20-25°C.

③ Vigorous growth stage. The suitable temperature is above 25°C. In the south, this begins in May; in the Yangtze and Yellow River basins, in June; in North China, from late June to early July; in Northeast China, in July. During this period, natural temperatures are sufficient for taro growth and development, and the main issue is fertilizer and water management, which should be applied vigorously to promote strong growth. The suitable temperature for corm formation is 28-30°C during the day and 18-22°C at night.

① Light intensity. Taro is a temperature-loving crop, and the light saturation point for photosynthesis is about 50,000 lx. In cultivation, light intensity must be coordinated with temperature levels to favor the formation of taro's growing organs. If light weakens, temperature should also decrease accordingly, while air humidity increases and respiration also decreases. Only in this way can taro's metabolic balance be favored. If light increases, temperature should also increase accordingly, which favors the accumulation of photosynthetic products. In protected cultivation, special attention should be paid to the close coordination of light with temperature, which favors growth and corm formation. When light is strong and temperature is high, increasing carbon dioxide concentration is even more favorable for the accumulation of photosynthetic products.

② Light quality. Also called light composition, it has a great effect on taro growth and development. Under blue-violet light (short-wave light), taro leaves are large and thick, and the petioles are thick and short. It is also favorable for the synthesis of vitamin C.

③ Effect of light duration on corm formation. Long light duration favors aboveground growth, while short light duration promotes corm formation. From a production perspective, in the early stage of vegetative growth, relatively long light and higher temperatures are required to promote an increase in leaf area, and then the plants should shift to a shorter-day environment to promote corm formation.

For seedling raising, in order to meet taro's growth needs, it is best to raise seedlings 20-30 days before the last spring frost, using cold frames or hotbeds, extended east-west, and selecting a site with higher terrain, sheltered from the wind and facing the sun. Bed soil thickness varies by variety, generally about 10 cm; it should not be too deep, because if the bed soil is too deep, transplanting is late and roots are easily damaged, and seedling recovery is slow. The bed temperature should be 20-25°C. Humidity should be appropriate, kept moist; the standard is that when soil is held in the hand, water appears between the fingers but does not drip. When sprouts grow to more than 4 cm, cultivation can begin early in open fields without frost. In South China, this can be done in February-March; in the Yangtze River basin, in early April; in North China, in late April; in Northeast China, in early to mid-May. This allows the plants to close rows before the summer solstice, maintain a relatively large assimilation area, and when the temperature gradually turns cool and sunshine becomes shorter, it favors corm tillering and enlargement and can increase yield. Water taros are generally planted when the seedlings are more than 25 cm tall to prevent them from being submerged and unable to grow and develop normally.

For planting, taro is relatively shade-tolerant and should be appropriately densely planted. In densely planted fields, the size of mother taros is close to that in sparsely planted fields, the number of daughter taros decreases, but the daughter taros are not small, and the yield per 667 sq m is significantly increased. For multi-corm taros, the row spacing is generally 80 cm and the plant spacing about 20 cm, and each 667 sq m can yield 3,000-4,500 kg of taro, with the highest reaching more than 5,000 kg. This planting method makes field operations relatively convenient, such as hilling, weeding, watering, and topdressing, and there are also very few exposed green taros. Taro should be planted deeply, generally requiring a planting depth of 16-18 cm; soil with sufficient fertilizer and water is suitable for dense planting, and it is best to open furrows for planting, then cover with mixed manure or fine soil to cover the seed taro while slightly exposing the bud tip. Water should be applied 3-5 days before planting to build soil moisture, and at planting, a small amount of water should be applied first, followed by planting. Before cultivating water taro, sufficient base fertilizer should be applied, the field should be harrowed, and water should be irrigated to a depth of 6-7 cm and left to sun for 3-5 days; when the water is 3-5 cm deep, insert the plants into the mud at a certain spacing. After the water taro recovers from transplanting, drain the water, sun the bed, and raise soil temperature so the taro grows well.

Taro likes water. Water taro has very strict requirements for moisture conditions, which is related to taro's growth habits and origin. Whether water taro or dry taro, both like moist natural environmental conditions.

During the seedling stage, temperatures are low and growth is slow, so more hoeing should be done to raise soil temperature, and the soil only needs to be kept moist. In the middle and later stages, vigorous growth requires sufficient water supply; if the climate is dry and temperatures are high, more watering is needed. Because hilling forms ridges, water can be applied from the furrows; each watering should be 6-10 cm below the ridge top, always keeping the soil moist, and watering again when the water in the furrow is almost dry. In the high-temperature summer season, water in the morning or evening; after autumn when temperatures drop, water at noon, so as not to damage the roots. During the rainy season, attention should be paid to preventing waterlogging.

After water taro survives planting, the water can be drained and the bed sunned to raise soil temperature and promote growth. Later, when fertilizing and hilling, the water can be drained to facilitate operations. After that, the water in the water taro field should always be kept at 5-7 cm. When summer temperatures are relatively high, the water in the bed should be kept at about 15 cm, and the water should be constantly changed to lower the temperature. After the Start of Autumn, when the weather turns cool, the water depth should still be kept at 5-7 cm. Before harvest, the water should be drained and the field sunned to promote the transfer of nutrients from the leaves to the corms, increase yield, and facilitate harvesting.

Taro likes fertilizer. Taro has a long growing period, requires a large amount of fertilizer, and is strongly tolerant of fertilizer. In addition to applying sufficient base fertilizer, it also needs multiple topdressings. During the seedling stage, growth is relatively slow and fertilizer demand is low, mainly relying on nutrients stored in the seed taro itself for growth; afterward, plant growth accelerates and fertilizer demand gradually increases, and this should be combined with hoeing, hilling, and watering at the same time. Generally, hill 3-4 times and topdress 3-4 times, gradually increasing the amount of topdressing. In the early stage, mainly nitrogen fertilizer is used to promote aboveground growth and form a certain leaf area, laying a foundation for the corm formation stage. During the vigorous growth stage, when hilling has already formed ridges, long-acting fertilizers such as decomposed livestock and poultry manure or cake fertilizer can be applied as topdressing, together with phosphorus and potassium fertilizers, to promote corm enlargement and starch accumulation. In the late growth stage, fertilizer and water should be controlled, especially nitrogen fertilizer, which should not be excessive, to prevent unbalanced aboveground excessive growth and underground growth, delayed maturity, and reduced yield.