I am trying to grow a mint plant in a water bottle.

While it worked great for a month, it has now stopped growing and current leaves are turning black and falling. What should I do?

There are three things to note:

  1. I snipped some stems to contain the plant.
  2. There is some fungal growth in the bottle
  3. It only receives about 2 hours of direct sunlight per day, but kept in 25 degrees Celsius ambient temperature. my mint plant
  • 1
    Does the plastic bottle have drainage? How often do you water the plant? Have you examined the roots yet? What was your motivation for planting the plant in this bottle? Why do you restrict access to light to only 2 hours?
    – Nikki
    Jun 4, 2023 at 1:55
  • 1
    @Nikki Has drainage, water it every 3 days. Examined the roots, look healthy. Light to 2 hours is a weather constraint, and the motivation for planting in this bottle is academic, wanted to challenge myself if it is possible to do this.
    – Cheeku
    Jun 5, 2023 at 12:55

1 Answer 1


There could be a number of reasons why your mint plant has black leaves and isn't growing as well as it should. Here are some suggestions:

Fungal or bacterial infection: Mint plants can get diseases like mint rust, powdery mildew, and black stem rot, which are caused by fungi or bacteria. These infections can cause the leaves to turn black, the plant to grow slowly, and other signs of damage. If this is the case, it's important to figure out which disease it is and treat it with the right fungicides or bactericides. Overwatering or poor drainage: Mint plants do best in moist soil, but they can die if the soil stays too wet or doesn't drain well. Overwatering can cause root rot, which makes it harder for the plant to take in water and nutrients, slowing its growth and changing the color of its leaves. Make sure the earth drains well, and change how you water based on that. Nutrient deficiencies: For good growth, mint plants need certain minerals. Lack of important nutrients like nitrogen, phosphorus, or potassium can make a plant grow slowly, turn its leaves yellow or brown, and make it weak overall. Think about using a balanced fertilizer made just for flowers to give them the nutrients they need. Pests or bug infestations: Some pests, such as aphids, spider mites, or caterpillars, can hurt mint plants, causing their leaves to turn black and their growth to slow down. Closely check your plant for signs of pests, such as insects, webs, or leaves that have been chewed. If there are bugs, you can get rid of them with organic poisons or other natural ways. Environmental conditions: Mint plants do best in well-lit places with a little bit of shade and prefer cooler temperatures. Too much heat or direct sunlight can stress the plant, which can cause the leaves to change color and growth to stop. In the same way, extreme cold can also hurt a plant's health. Make sure your mint plant is in a good spot with the right amount of light and warmth.

To fix the problem, look closely at your mint plant for signs of disease, pests, or stress from the surroundings. Change how you water and feed your plants, make sure they have enough light, and think about using the right treatments or cures for the problem you've found. If the problem keeps happening or gets worse, it can be helpful to talk to a local gardening expert or plant professional to get an accurate diagnosis and customized answers.

  • 3
    It sounds like chatgpt. We really want to hear from you. Jun 4, 2023 at 21:02
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