Cold and Frost Prevention Measures for Tea Gardens in Xiangxi Prefecture

According to important weather forecasts from provincial and prefectural meteorological departments: influenced by cold air, our prefecture will experience a strong cold wave and low temperature, snowy, and icy weather with significant temperature drops that will last for an extended period, potentially impacting tea production. Based on the actual development of our prefecture's tea industry, the following cold and frost prevention measures and recommendations are proposed. Please take effective actions according to your local conditions, all relevant tea authorities, tea enterprises, and tea farmers, to minimize losses in tea gardens.

I. Cold and Frost Defense for New Tea Gardens

1. Terrain Selection. New tea plantations should avoid unfavorable terrains and be established preferably on south-facing, wind-sheltered, and sunny slopes where backdrafts and gully winds are less likely to occur.

2. Selecting Cold-resistant Varieties. Choose suitable tea varieties based on altitude and terrain factors.

3. Reasonable Planting Time. Avoid planting new tea plants during cold periods (when temperatures are below 5°C). In high-altitude areas, early spring is the best time for planting.

4. Establishing Windbreaks. For tea gardens located in windy areas prone to frost damage, intentionally retain some existing trees or establish windbreaks to shield against cold currents and expand the leeward area, improving the microclimate within the tea garden. This is a permanent protective measure. Windbreaks generally use fast-growing tree species, combining trees and shrubs, with the effective wind protection range being 15-20 times the height of the trees.

II. Cold and Frost Defense for Existing Tea Gardens

Cold and frost prevention in tea gardens mainly focuses on reducing frozen soil depth and preventing leaf freezing. Measures such as straw mulching on the ground can reduce the depth of frozen soil, mitigating the extent of root freezing; covering the canopy can prevent leaf freezing and excessive transpiration caused by dry, cold winds. The following are some common frost prevention measures:

1. Smoking Method. When cold air affects the area, use easily combustible materials like weeds, rice straw, crop stalks, branches, sawdust, rice husks, turf, etc., to create smoke piles around the tea garden. Burning these materials produces smoke, which reduces nighttime heat radiation from the ground and tea plants, creating a “greenhouse effect” that retains heat and reduces radiative frost damage. Smoking should ideally begin at around 10 PM.

2. Barrier Method. To address the cause of frost formation, which is the influx of cold air, erect wind barriers above where cold air enters. This reduces air currents, decreases evaporation in the tea garden, and maintains relatively stable air and soil temperatures, providing protection.

3. Garden Mulching. Mulching includes both ground and canopy mulching. Ground mulching (mulching between rows) can use locally sourced materials like brushwood, rice straw, crop stalks, turf, barnyard manure, etc., to cover the space between tea plants and their roots. This helps raise soil temperature, maintain soil moisture, and has a very significant frost prevention effect. Covering the canopy with straw can protect against snow, frost, or low temperatures, offering some frost resistance, but the canopy should not be covered for too long or too tightly. Where conditions permit, or for young tea plants, plastic film, shade nets, and mulch films can be used, which are beneficial for wind, frost, and ice protection, reducing soil heat loss and raising ground temperature, thus enhancing the tea plants' cold resistance. When late spring cold spells occur, canopy covering is highly effective in preventing frost.

4. Root Collar Mounding. Mounding soil around the root collar increases soil thickness, enhances soil vitality, retains water, and provides insulation. It also prevents soil “aging.” For shallow and nutrient-poor tea gardens, mounding should be done promptly after applying base fertilizers, with 8-10 cm of fresh soil piled around the base of the tea plants to prevent root exposure and resulting frost damage. For terraced tea gardens, mounding is particularly important; for young tea plants, protecting the root collar is a key winter frost prevention measure.

5. Timely and Appropriate Fertilization. Timely deep plowing and fertilization should be conducted in autumn and winter. Avoid or limit the application of quick-release fertilizers in late autumn to prevent new shoots from freezing in winter. Base fertilizers should be applied as soon as possible after the harvest season ends. If delayed, injured roots may not recover and grow in the same year, leading to more severe frost damage in winter. In high-latitude and high-altitude areas, where temperatures drop rapidly in late autumn or early winter, and the growth of both above-ground and underground parts of tea plants ceases earlier than in general tea regions, fertilization should be done earlier.

III. Post-Snow Management Measures

1. Manual Snow Removal. When there is accumulated snow on the tea canopy, manually remove the snow from the canopy in a timely manner.

2. Timely Pruning. For tea plants affected by frost, once temperatures have stabilized, prune the damaged branches and leaves to encourage new growth. For severely frost-damaged tea plants, deep pruning or stump cutting may be necessary.

3. Strengthen Water and Fertilizer Management. Apply quick-release nitrogen fertilizers, increase phosphorus and potassium fertilizers, organic fertilizers, or spray efficient compound fertilizers (0.3% urea + 0.2% potassium dihydrogen phosphate) on the foliage to enhance the plants' cold resistance and help them recover and strengthen their vigor.

4. Rational Picking. Frost damage can delay the start of picking in tea gardens and result in significant yield reduction. During Spring Tea picking, implement leaf retention picking to help the plants recover and strengthen their vigor. For tea gardens that have undergone heavy pruning or stump cutting due to frost damage, start rebuilding the canopy from scratch.

Tea Industry Development Center of Xiangxi Prefecture
Tea Research Institute of Xiangxi Academy of Agricultural Sciences
Comprehensive Test Station of National Tea Industry Technology System in Xiangxi
February 4, 2024