Mint (Lamiaceae) Cultivation Methods and Precautions, Plus Yellowing Leaf Treatment and Pruning
Mint, known locally as “yindancao”, is a plant of the Lamiaceae family, also called wild mint and yexixiang. Long known as the “lazy person's herb”, it can be said to be a very easy plant to grow, so what are the methods and precautions for growing mint? Let's take a look together.
Mint grows mostly in mountain wilds, wetlands and beside 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. The whole plant is fresh and aromatic. The leaves are opposite, the flowers are small and light purple, lip-shaped, and after flowering it produces small dark purple-brown seeded fruits.
Mint is one of the commonly used traditional Chinese medicines. It is a pungent, cool diaphoretic and antipyretic medicine, used to treat influenza, headache, red eyes, fever, sore throat, swollen and painful gums and other conditions. Applied externally, it can treat neuralgia, skin itching, rashes and eczema, etc. Ordinarily, mint is used as a tea to clear the heart and brighten the eyes.
Mint harvested from light-frame greenhouses is also a fresh vegetable on the Spring Festival table. It is refreshing and tasty. In China, mint production is largest mainly in Jiangsu and Anhui provinces.
Growing essentials
Soil
For mint cultivation, choose a loose, well-drained, fertile sandy soil.
Temperature
The growing temperature should preferably be kept at 20-30°C, and mint has strong cold tolerance, able to endure low temperatures of -15°C.
Light
Mint naturally likes sunlight, so sufficient light should be ensured; this effectively ensures normal flowering of mint and promotes the accumulation of peppermint oil and menthol.
Water
Mint cultivation requires relatively more water, and usually the potting soil should be kept somewhat moist, especially in the early and middle growth stages. During the flowering period, the water supply can be appropriately reduced.
Planting
When selecting branches, dig up thick white rhizomes for planting, trim them into root sections about 8 cm long and bury them in the potting soil. After about 20 days, new branches can sprout. You can also cut tender stem tips and carry out shaded cuttings in May-June.
How to water mint?
Mint likes water very much, and when grown outdoors on a balcony it can be watered every day. Actually, young mint is not afraid of drought or waterlogging and has good growth and adaptability. A sufficient water supply ensures that new leaves are tender. Old mint has aging roots and elongated stems, which affects the water supply to the leaves. You can combine watering with foliar misting to ensure the water supply. For watering, simply sprinkle water directly above the plant with a spray bottle. No need to water at the roots, and no need for bottom absorption. Different varieties differ in water needs: those with more and denser leaves need more water; those with fewer and sparser leaves need less water.
Mint pruning methods
When the plant is growing vigorously, the pruning frequency for mint is best set to once a week, and weak branches, dead branches and thin branches should all be cut off.
After pruning is completed, spray with xingaozhimo for effective disinfection, then place it in a sunny spot, which can help further healing of the tissue at the cut and thereby promote the sprouting of new branches.
Analysis of the causes of yellowing mint leaves and treatment methods
1. Abrupt environmental changes cause yellowing mint leaves: 1. Leaf yellowing caused by overly wet watering. Usually watering should not be too wet; overly wet soil easily accumulates water, causing root rot and leaf yellowing. 2. Hard, impermeable soil means that after watering, the water cannot penetrate into the soil layer, so most roots cannot absorb water and nutrients, resulting in leaf dehydration and nutrient deficiency, with symptoms of yellow, drooping leaves.
Solution: It is best to water after the soil dries, and follow the rule of not watering until dry. This benefits root growth and makes leaf yellowing less likely. The best approach is to loosen the soil appropriately, which helps make the soil loose, breathable and well-drained, benefiting root growth.
2. Overwatering causes yellowing mint leaves (water yellowing): When watering curly mint, note that if the soil surface is not dry, do not water; if dry, water thoroughly. The water used can be plain water, and preferably rice-washing water from home, which is both nutritious and saves water.
Solution: Just pick off the yellow leaves, and be careful not to water too much; mint has very strong vitality. Even if after a while the leaves and stems all wilt, do not think it is dead. You only need to cut off the withered parts and wait quietly for new shoots to sprout. Do not throw it away!
3. Long-term water shortage causes yellowing mint leaves (drought yellowing): Wilting, scorching, and the leaves also become shriveled.
Solution: Mint is a very easy plant to grow. Usually, cultivation failures are due to lack of water, causing the plant to wither and die. But if there are white objects on your plant, it may also be caused by pests and diseases. If the external window of an indoor balcony is not opened, ventilation is poor, and pests and diseases are more likely to occur. When this happens next time, it is recommended to prune the stems to 1/2 of their original length and spray some insect-repellent liquids, such as neem oil and lavender essence. Usually healthy new branches will grow again. If water and pests and diseases are well controlled, and there is also good light and ventilation, mint can grow very well.
4. Dry air causes yellowing mint leaves: Dry, withered leaf tips or scorched leaf edges appear.
Solution: Attention should be paid to methods such as misting and covering with plastic film to increase air humidity.
5. Insufficient sunlight causes yellowing mint leaves (light-deficiency yellowing): Long-term overly dark conditions easily cause symptoms of yellow leaves.
Solution: It is best to place it indoors in a sunny, ventilated spot, which benefits photosynthesis and reduces the problem of yellow leaves. It is better to move it outdoors to bask in the morning and evening sun for 1-2 hours.
6. Too-high temperature causes yellowing mint leaves: If the winter room temperature is too low, flowers that like high temperatures are often susceptible to cold damage, thus causing leaves to turn yellow and, in severe cases, to wither, turn yellow and die.
Solution: Attention should be paid to adjusting the room temperature in time. It should be moved promptly to a well-ventilated, cool place.
7. Too-low temperature causes yellowing mint leaves: If the room temperature is too high, the plant's transpiration is excessive, and the roots cannot meet the demand for water and nutrients, which can also make the leaves turn yellow.
Solution: Attention should be paid to adjusting the room temperature in time.
8. Overfertilizing mint causes yellowing leaves (fertilizer yellowing): New leaves are thick and fleshy and mostly uneven, while old leaves have dry tips, scorched edges and fall off.
Solution: Fertilization should be stopped immediately, and the amount of watering increased so that the fertilizer flows out from the drainage holes at the bottom of the pot. Or immediately repot, rinse the root ball with water, and then replant it in the pot.
9. Root rot causes yellowing mint leaves: Leaves show longitudinal wrinkling and deformity.
Solution: Find the rotted root area and use scissors to cut off the rotted roots from their base.
10. Pests and diseases cause yellowing mint leaves: Leaf spot disease caused by infection by fungi and other pathogens easily causes local necrosis of leaves, with yellow spots or patches appearing, and in severe cases the whole leaf withers, turns yellow and falls off. After infection by mosaic virus, yellow-green mottling appears on the leaves; when damaged by scale insects, red spider mites and the like, the leaves also become partially yellow and withered, or even the whole leaf wilts, turns yellow and falls off.
Solution: In all cases, pesticides should be sprayed promptly for prevention and control.
Mint benefits and effects