I like to grow mint in my container herb garden because it’s one of my favorite Indian herbs. But in the past, I found that the mint plant was dying and I had to fix the problem.
Your potted mind plant is dying because you are overwatering it. The excess water will cause potting soil to remain damp and the roots to drown. This causes fungal issues like root rot which reduces the nutrients and oxygen reaching the plant causing it to die.
My post below will help you find out why your mint plant is dying and what you can do to get it back to health again.
The most common cause for mint plants to die is overwatering. We feel that the plant is not getting enough water and keep watering it.
If the potting soil is not good or there are not sufficient drainage holes in the pot, the water will collect in the soil. This causes the roots to drown in the moisture.
The roots cannot supply the required nutrients and oxygen to the mint plant. They will also develop fungal issues like root rot due to the humid conditions and start dying.
You can avoid overwatering by ensuring you water the mint plant only when required. Stick your finger 1-2 inches deep into the potting soil and check for moisture. Only water if the tip of your finger does not feel moist.
Make sure the pot you’re growing mint in has sufficient drainage holes at the bottom. So the excess water will drain out from them.
If the roots are already suffering from root rot, you’ll see they are soggy, black, and emitting a foul smell. You’ll need to remove the plant from the pot and cut off those roots.
You need to sterilize the pot in a solution of 1 part bleach and 9 parts water for an hour. Rinse it with clean water and let it dry.
You can then add fresh potting soil to the pot and replant the mint plant so it’s free from fungal problems.
If you don’t provide your potted mint plant with sufficient moisture, the plant will start to die. The roots are unable to provide nutrients and moisture to the plant due to a lack of water.
This problem may happen if you neglect to water your plants. Maybe you are forgetting to water them or are too busy to water the mint plant when needed.
I recommend you check on your mint plant every morning for watering. Stick your finger 1-2 inches into the potting soil and check for moisture. If the tip of your finger is dry, you need to water it.
If you don’t have the time or are forgetful, I would suggest growing the mint plant in a self-watering container.
This comes with a reservoir at the bottom of the container that holds water so the plant always has a supply. You just need to occasionally fill the reservoir with the required water and it will last for days.
3. Too much heat
Mint is a cool-season plant that is best to grow in early spring or late fall. It’s best to grow potted mint in temperatures between 50 to 75 degrees Fahrenheit.
If the weather becomes too hot beyond 75 degrees, the potted mint will start dying. You need to make sure that the mint is away from direct sunlight in hot conditions.
You can bring the potted mint indoors where it will have a much cooler environment. You can make use of a row cover that could protect the mint plant from the direct heat of the sun.
4. Poor potting soil
The worst mistake you can make is growing potted mint in poor potting soil. This will cause problems like root rot, lack of nutrients, and diseases that will kill the plant.
I recommend using sterile potting soil that is specially made for growing potted plants. It’s not good to use garden soil for your mint plant.
The garden soil may contain too much clay that will cause moisture to remain in the soil longer leading to overwatering. Or it may contain a lot of sand that drains the water fast before the roots can absorb it.
The garden soil may contain pests, diseases, and chemicals that will harm the mint plant and also cause problems for those who eat it.
You can make your own potting soil by mixing in 1/3 perlite, 1/3 vermiculite, 1/3 coco coir, or peat moss.
5. Lack of nutrients
If the potted mint plant does not get sufficient nutrients from the potting soil, it will start dying.
I suggest adding compost to the potting soil when preparing it for growing potted mint. You can add 1-2 inches of compost to the potting soil.
The compost will add the required nutrients to the soil and also beneficial organisms that will process organic matter and keep introducing nutrients as the plant grows.
If you don’t have compost, you can mix in some slow-release organic fertilizer to the potting soil. The nutrients will release into the soil as you water the plant.
Once the mint plant has started growing, you can add the compost or slow-release fertilizer every month to the potting soil.
You can also use a liquid fertilizer instead that will provide quick nutrients to the mint plant. You can dilute the liquid fertilizer and spray it on the foliage as well as the potting soil.
Make sure to follow the manufacturer’s instructions when using organic fertilizer so that you know how much and how often you need to use it.
6. Lack of growing space
If the mint plant does not get sufficient space to grow, it will cause a lack of nutrients and oxygen. This may cause the plant to die.
You want to keep a space of at least 18-24 inches between mint plants. Otherwise, they will compete with each other for nutrients and resources.
Growing the plants close to each other will also lead to humid conditions that attract fungal diseases to the potted plants.
You also want the pot to be of sufficient size that the mint plant can grow well in it. If space is less, the plant will become root-bound where the roots are circling around the pot causing a lack of moisture and nutrients.
If you find that the water is just flowing out of the drainage holes as soon as you water the plant, it may be root-bound.
You need to remove the mint plant from the pot and check the roots. If they are circling, you need to untangle them and maybe even peel off a layer. Then plant the mint in a bigger pot that is suitable for growing the larger plant.
Your mint plant like other plants can get attacked by pests and diseases that will kill them. So you need to make sure you keep them away from such issues as much as possible.
Many pests don’t prefer the smell of mint and will stay away but there are still lots of insects that will feed on the plant.
This is not a problem when the infestation is small but when it becomes a large issue your leaves will start falling due to stress and lack of nutrients.
I recommend checking on your potted mint plant every morning for signs of such pests. The sooner you take care of the problem, the less damage to the plant.
You can knock some of these pests like aphids and thrips from the mint plant by a spray of water and drop them into the soil. For some others like mealybugs and slugs, you can pick them off the plant and dump them in a bucket of soapy water.
It might not be easy to get rid of some of the pests and you may need to consider fungicide options like neem oil, horticultural oil, and diatomaceous earth.
Some diseases like mint rust, leaf spot, and powdery mildew may attack the potted mint plant and kill them.
You can avoid fungal diseases by keeping the potted mint plant clean and away from humid conditions.
Avoid watering the leaves of the mint plant and only spray water on the potting soil near the base. Don’t grow mint plants too close to each other as that reduces air circulation.
Try to get mint seeds or seedlings that are resistant to some of the bacterial and viral diseases affecting the plant.
If you find that certain parts of the mint plant are affected, you can cut those off to reduce the spread of the disease. If you find that the plant is too infected, you need to dispose of it so it does not affect other plants you are growing.
Can You Revive a Dead Mint Plant?
Sometimes it’s possible to revive a dead mint plant. You might start watering it more often or let it sit in direct sunlight to dry the soil. Replacing the soil could vastly improve the nutrient content the root system needs to pick back up. Experimenting with different solutions will help you find what your plant needs.
If you’ve tried everything and you still don’t have any luck, it may be because your mint plant has gone dormant. They often “die” during cold winter months, but if left alone, they’ll come back in the same place when spring begins. Leaving your pot by itself and moving it into the spring sunlight may reveal that your plant never really died to begin with.
Sometimes even the most experienced gardeners don’t have good luck. You could identify the problem with your mint plant, but it’s too late to do anything about it. If that’s the case, you can always try again or grow other beginner plant varieties to expand your skillset before returning to your herb garden dreams.
What Are Common Mint Plant Pests?
After closer inspection, you think you may have found evidence of pests. How do you know which pests you’re dealing with? These are the most common mint plant pests and how you can get rid of them after quarantining any infected plants.
Spider mites are tiny insects that create webs between leaves. You might not spot them immediately, but it’s difficult to miss their webs. Once the adults make homes on the underside of your plant’s leaves, a female can lay up to 100 eggs that hatch every three days.
You can get rid of these pests with insecticide sprays or by washing each leaf with soap and warm water. Repeat the treatment daily until no spiders appear.
If tiny black bugs are eating holes through your plant, you might have a flea beetle problem. Anyone can end the infestation by shaking talcum powder over the leaves or spraying their plant with a diluted mix of water, rubbing alcohol, and soap. Continue daily treatments until the beetles are gone.
Tiny green worms inching across your mint plant are probably loopers. They’ll eat away at your plant before turning into moths, then returning to lay eggs and repeat their life cycle. Loopers and their eggs are easy to see, so you can pluck them off your plant’s leaves. Spraying your plant with vinegar after removing pests also prevents any remaining eggs from hatching.
Aphids are tiny bugs no larger than your pinky fingernail. Sometimes they’re green and other times they’re brown. They leave behind a sticky yellow substance that often balls up, so it’s clear when they’ve made a home in your indoor plants, as large populations can turn leaves yellow.
Washing your plant’s leaves with mild soap and water every day for two weeks will take care of any aphids and whatever eggs they lay on the underside of big leaves.
Elongated black or straw-colored bugs that leave splotchy or silvery leaves behind are thrips. They also lay eggs in the soil that hatch quickly, so take action if you find them along with your mint plant.
Spraying your plant with insecticide or washing it repeatedly with insecticidal soap will provide a strong defense against current and future invasions.
Tiny brown caterpillars living in your plants are likely cutworms. They feed off the roots and base of plants, so they often blend into the dirt and surprise even the best gardeners.
Spread diatomaceous earth around your mint plant and spray an insecticide for a simple, two-step mitigation technique.
What Diseases Affect Mint Plants?
Pests aren’t the only reasons why potted mint plants die. They can also suffer from these diseases — some of which don’t have any cures.
Otherwise known as Puccinia menthae, mint rust presents as discolored leaf spots and brown, distorted stems. There isn’t a cure for mint rust, but you can trim off any affected parts of the plant and watch the rest to see if it recovers.
Leaf spot is different from mint rust because although they both cause spotting on leaves, it won’t affect or twist the stems. The spots also often have a yellow halo. Some fungicide sprays treat leaf spot because it’s so common, so check labels carefully to find the right product to save your mint plant.
Soil can become home to stem rot, infecting the root system and parts of the stem underneath the dirt. When the rot takes over your plant, the leaves yellow and wilt. You may find a fungicide spray to treat this disease, but the best treatment is to remove your plant from the infected soil, rinse the roots, and repot it in fresh dirt.
White spots, splotches, and fuzzy growths on your mint plant are most likely powdery mildew. This common fungus dies when gardeners use a fungicide or spray their plant with a mixture of baking soda and water.