Detailed Explanation of Mint Planting Techniques and Management Methods

Mint, also known as wild mint, is a perennial herbaceous plant that mostly grows in mountain wetlands and by rivers, with rhizomes creeping underground. The whole plant has a fresh, aromatic scent, with opposite leaves and small light purple flowers in a lipped shape, producing small dark purple-brown seeds after flowering. Mint prefers warm, humid environments with plenty of sunlight and abundant rainfall. It is produced throughout the north and south, growing in moist areas by water, at altitudes up to 3500 m. Mint is one of the commonly used traditional Chinese medicines. It is a pungent, cooling diaphoretic and antipyretic drug, used to treat influenza, headache, red eyes, fever, sore throat, swollen and painful gums, and other conditions. For external use, it can treat neuralgia, skin itching, rashes, and eczema.

Seedling Raising

1. Rhizome propagation: Cultivate seed roots in late April or late August. In the field, select robust plants free of pests and diseases as mother plants, and plant them at a spacing of 20×10cm. After harvesting the aboveground stems and leaves in early winter, leave the rhizomes in place as seed plants.

2. Division propagation: When mint seedlings are about 15cm tall, thin and fill in the seedlings. Use the thinned seedlings for division and transplanting.

3. Cutting propagation: In May-June, cut the aboveground stems and branches into 10cm-long cuttings, and insert them in a prepared seedbed at a row spacing of 7×3cm for seedling cultivation. After rooting and sprouting, transplant them to the field for cultivation.

Transplanting

1. Transplant mint in early spring of the second year before it has sprouted. Early planting leads to early sprouting, a longer growth period, and higher yield. When planting, dig up the rhizomes, select thick, short-jointed, disease-free rhizomes as seed roots, cut them into 7-10cm small sections, then open 10cm-deep furrows on the prepared bed at a row spacing of 25cm. Place the seed roots obliquely in the furrows at a plant spacing of 10cm, cover with fine soil, press firm, and water.

2. Pinching and topping: In May, when the plants are growing vigorously, promptly remove the terminal buds to promote the growth of lateral branches, stems, and leaves, which helps increase yield.

First-cut period management (from emergence to the first harvest)

1. Check seedlings and fill gaps: After the field has basically full stands, check the seedlings promptly and replant missing or sparse spots and patches.

2. Intertillage and weeding: After full stands, carry out intertillage and weeding between rows and manual weeding between plants to preserve soil moisture, increase (soil) temperature, eliminate weeds, and promote seedling growth. Carry out intertillage and weeding 2-3 times before row closure. Before harvest, pull out all weeds in the field to prevent the odor of other weeds from affecting the quality of mint oil.

3. Timely topdressing: When the seedlings are 10-15cm tall, open furrows and apply topdressing, applying urea l0kg per mu. After row closure, spray twice per mu with 5ml spray additive + 150g potassium dihydrogen phosphate + 150g urea.

4. Scientific watering: Mint needs more water in the early and middle stages, especially in the early growth stage when the root system has not yet formed, so it needs more water. Generally water about once every 15 days, and water 4-5 times from emergence to harvest. After row closure, water lightly and appropriately to avoid excessive stem and leaf growth and lodging, which can cause lower leaves to fall off and reduce yield. Stop watering 20-25 days before harvest. At harvest time, the ground should preferably be “pale.”

5. Disease control

① Black shank, which occurs at the seedling stage. Symptoms are shrinkage and sunken lesions at the stem base, blackening, rotting, and plant lodging and wilting. For control, during the disease period, apply 70% chlorothalonil or 40% carbendazim 100-150g per mu, diluted with water and sprayed.

② Mint rust, which occurs easily from May to July. Spray leaves with a 25% triadimefon 1000-1500 times solution.

③ Leaf spot, which occurs from May to October. In the early stage of disease, spray a 65% zineb 500 times solution once a week to control it.

6. Pest control

The main pest of mint is the “bridge-forming caterpillar,” with damage periods around mid-June and late August. Generally, when the pest density reaches 10 insects/m2, use 15-20ml deltamethrin per mu and spray 1-2 times, or spray with 80% dichlorvos at 1000 times.

7. Timely harvest

In early July, when 10-30% of the flower buds on the main stems of mint are in full bloom, begin harvesting. At harvest, cut the upper stems and leaves evenly at ground level. Spread the cut mint out to dry immediately; do not pile it up, to avoid fermentation. Harvesting mint too early reduces the oil yield, while harvesting too late increases the furan content in the mint and affects oil quality. Bundle the wilted mint promptly for later distillation and oil refining.

Second-cut period management (from after the first harvest to before the second harvest)

1. The second-cut period of mint has a relatively short growth period. After the first cut, promptly and quickly sweep up fallen leaves for distillation and oil refining. Remove stubble, weeds, and creeping stems from the ground as soon as possible (generally hoe to a depth of 2-3cm) to encourage the young buds of the second-cut seedlings to emerge from the rhizomes.

2. After hoeing the stubble, water immediately to promote early sprouting and rapid growth of the second-cut seedlings, extend the growth time, and increase yield. Water 3-4 times during the second-cut period. When the seedlings are 10-15cm tall, broadcast (or furrow-apply) urea l0kg per mu, apply foliar topdressing 1-2 times, and pull large weeds 1-2 times before harvest so that there are no weeds in the field before harvest.

Harvest

1. The harvest time is from mid-September to mid-October.

2. When dried to 70-80% dry, tie into small bundles and continue drying until fully dry. The best quality is dry, full of leaves, with dark green leaf color, purple-brown or light green stems, and a rich aroma.