How to grow mint? Mastering these cultivation techniques is key

Mint, commonly called “Yindancao”, is a plant of the Lamiaceae family, that is, the dried whole plant of other species in the same genus. It mostly grows in mountain wild wetlands and by rivers, with rhizomes spreading horizontally underground, mostly growing at an altitude of 2100 m, but it can also grow at an altitude of 3500 m. It is an aromatic crop with special economic value. Let us take a look at mint cultivation techniques below.

I. Site Selection and Land Preparation

It has low requirements for soil and can be cultivated in any soil except overly acidic and overly alkaline soils. Choose scattered land with drainage and irrigation conditions and sufficient light, such as beside ponds, houses, and water channels, with fertile soil and flat terrain being best. Sandy soil, land with insufficient light, and land prone to water accumulation in drought are not easy to plant. Land that has grown mint must be left fallow for about 3 years before it can be planted again. This is because residual underground roots affect yield. Prepare the land and plow deeply, apply decomposed compost, farmyard manure, superphosphate, bone meal, and other materials as base fertilizer at 37500-45000 kg per hectare, harrow finely, hoe shallowly once, turn the fertilizer into the soil, break up the soil, and rake it level to make beds 200 cm wide.

II. Seedling Raising and Propagation

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 20×10 cm. 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 15 cm tall, thin and fill in seedlings. Use the thinned seedlings for division and transplanting.

3. Cutting propagation: In May-June, cut aboveground stems and branches into 10 cm long cuttings and insert them on a prepared seedbed at a row spacing of 7×3 cm for cutting propagation. After rooting and sprouting, transplant them to the field for cultivation.[4] 

Transplanting

1. Transplant mint in early spring of the second year before it has sprouted. Early planting leads to early sprouting, a long growth period, and high yield. When planting, dig up the rhizomes, select thick, short-internode, disease-free rhizomes as seed roots, cut them into 7-10 cm long sections, then open 10 cm deep furrows on the prepared bed surface at a row spacing of 25 cm. Place the seed roots diagonally in the furrows at a plant spacing of 10 cm, 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.

III. Field Management

1. Check seedlings and replant. 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 harvesting, 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 seedlings are 10-15 cm tall, open furrows and apply topdressing at 10 kg urea per mu. After row closure, spray twice per mu with 5 ml Pen Shi Bao + 150 g potassium dihydrogen phosphate + 150 g 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. Generally water about once every 15 days, and water 4-5 times from emergence to harvest. After row closure, water lightly as appropriate to avoid excessive growth of stems and leaves, lodging, shedding of lower leaves, and reduced yield. Stop watering 20-25 days before harvest.[5] 

IV. Pest and Disease Control

Disease control

The main disease of mint is black shank, which occurs at the seedling stage. Symptoms are constriction and sunken areas at the stem base, blackening, rot, lodging, and withering of plants. For control, during the disease period, use 100-150 g of 70% chlorothalonil or 40% carbendazim per mu, dilute with water, and spray.

Mint rust is prone to occur from May to July. Spray leaves with a 1000-1500 times dilution of 25% triadimefon.

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

Pest control

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