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Why Mint Leaves Turn Brown & Are They Still Safe

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Got a fresh mint plant at home, just waiting to be used for a drink of a fresh ingredient in food ? Then you’re going to need to pick some mint leaves ! Are some of them brown ? Are they entirely brown or just brown spots ? Are the stems dried up ? 

There are several causes for brown mint leaves, and we’ll explore them in this post. We’ll also talk about whether you can prevent the leaves from developing those brown spots, and if it’s safe to eat the ones already browned. Read on !

Why do mint leaves turn brown ?

Mint leaves can turn brown for several reasons, including fungal infections, pests, water or sun/heat issues, old age, and sometime storage issues. In most cases it’s best not to eat or use browned mint leaves, with the exception of mint dried specifically for tea.

What issue the mint has depends on what the leaves look like, whether they’re still on the plant, and what the plant looks like. Here’s a more detailed breakdown of the possible reasons your mint leaves may be turning brown. 

Dehydration or sunburn only browns the leaves at the edges

If your mint gets too much sun and/or not enough water, its leaf edges may dry and appear brown. Those areas will also be a bit crumbly if you touch them. These brown spots can’t be reversed but you can take steps to ensure your mint won’t have further issues. 

Move the plant somewhere shady but bright – like near a window but not in direct sunlight. And water your mint in small amounts twice a week, or when you notice the top inch of soil is dry. 

Fresh (on the plant) mint leaves may have an health issue

If the leaves are still on the plant but are developing brown spots, the issue may be with the plant’s health. Fungal infections are usually the result of Puccinia menthae, a fungus which causes mint rust. The leaves develop small dry brown spots all over the leaves, and they get progressively larger until they turn into leaf blight. That is when the infection takes over the entire leaf and even goes down into the stalk. 

In these cases the infection can and will spread to the rest of the plant, so it’s best to cut off those parts as soon as you see them. If the stalk is already infected, you need to cut about half an inch under where the infections is visibly present. 

Do not eat browned mint leaves if they have a fungal infection !

Read also: Why Is Peppermint Associated With Christmas ? 

Picked mint leaves may be just breaking down

Are your mint leaves pre-packaged ? They could be turning brown due to the excess moisture in the package, and if this is the case they will also be soft and mushy. These are leaves you should not use as they’re essentially breaking down. 

The good news is that it’s likely not all leaves in the package are breaking down. Remove the leaves that are still good, and package them in a simple small plastic baggie and keep them in the fridge, for later use. 

Please note that these leaves usually don’t last long. Just like pre-packaged salad mixes, pre-packaged mint leaves are only good for 3-5 days before they start to break down. So if you do buy mint leaves, you may want to use them in the next day or two after you buy them. If you know you won’t be using all of them, pick the leaves off the stalks and freeze them. The best method we know is to freeze fresh mint leaves in ice trays, so you get cubes of fresh minty ice whenever you need them. 

Dried mint leaves always turn brown

Are your mint leaves picked and dried, to be used for tea ? Then the brown tint to them is normal. If your mint leaves are fresh and you steep them in hot water for tea, they will also turn brown as the chlorophyll disintegrates. 

Dried mint leaves, meant for tea.

Older mint plants may have some brown leaves near the soil

If your mint plant is old, as in it already produced at least 1 set of flowers this season, it may try to get new leaves in but they will fail. This usually happens near the base of the plant, and those leaves will turn brown. That’s fine, as long as the stalks themselves don’t turn brown as well. 

Read also: Can You Eat Cold Chicken Nuggets? And How To Reheat Them

Can you still use mint leaves that are a bit brown ?

Mint leaves that are already brown can still be safely used in food and drinks as long as the brown is from dehydration or sunburn. We don’t recommend using browned mint leaves that are the result of an insect or fungal infestation. The insect eggs may still be on the leaves, even after washing, and the fungal infection may cause you harm. 

What if your mint already has a fungal infection ?

If your mint plant has a disease already, there isn’t much you can do. If you bought the plant from the supermarket and didn’t notice some brown leaves, that happens. If it’s just the leaves that are brown, you can remove them and watch the plant for a day or two to see if it spreads. If the infection is still there other leaves will start browning as well. if this is the case you should also see some stems and stalks turning brown and drying up. 

In this case you can either cut about half an inch under the damage and hope for the best, or discard the plant completely. Fungal infections spread very fast, so it’s very likely the whole plant is already doomed. 

If you notice any sign of infection at all- fungal or insect – keep the plant away from your other plants, at least a few feet. Fungal spores are airborne and can float onto other plants when you handle an infected plant, and insects may reach onto neighboring plants if they are nearly touching. 

What can you do with browned mint leaves ?

If your mint has already browned and it’s not dehydration or sunburn, there’s not much you can do with the damaged leaves. They can’t be used as compost since the fungal infection will spread to other plants, and if the issue is insects they will propagate to other plants. So in short, aside from discarding them, they can’t be used. 

Read also: Why Is Arugula Bitter ?

How to check if mint is still good to eat

Browned mint leaves may still be good to use, and even fi your mint hasn’t started turning brown you may still want to check if the plant is still good. here’s a quick two-step check for mint leaves. 

Smell the mint, it should be fresh

Smell the plant or leaf and see if it still smells fresh and minty. In most cases brown leaves won’t smell at all, or if they do smell it won’t be fresh. If the smell is not there or if it’s off, don’t use the mint. 

If your mint isn’t brown there is no real reason for it to ever stop smelling minty. Don’t expect a mint smell like chewing gum, expect more of a mix between grass(herb) and mint. 

Look at the texture of the leaves

Leaves on a mint plant that is still good to eat are fresh, tender, and they hold their shape very well. They are not dry or scratchy, nor are they soft and squishy. They have tiny little hairs on them, which should feel very soft. 

Older mint leaves, when the plant has matured, will feel a little tougher and may feel woody towards the stem. These leaves are still okay to use, but they may have less flavor than the young, tender leaves. 

How to keep your mint leaves from turning brown

Your mint plant is a very hardy plant, but it can still suffer if you don’t treat it right. Here are some of the most common ways to ensure your mint plant will be healthy, green, and fresh for as long as possible. Most of these apply to other herb plants, like basil and rosemary or parsley. 

Don’t over or underwater 

A good rule of thumb for any aromatic herb is to only water when you notice the leaves drooping a little, or twice a week if you live somewhere quite warm. Mint tends to like higher moisture in the air and soil, but it is not a fern or moss, so give it just a little more water than your average house plant. 

But of course, mint does not like standing water so always use a very well draining soil and pot. Mint likes soil that is moist, but not waterlogged.

If you want to make sure the plant needs water, put a finger into the top inch of soil. If the whole inch is dry, then it can be watered. 

Read also: Why Do Bananas Turn Brown In The Fridge ?

Water the stalks and soil, never the leaves

This is the case for most plants actually. Fungal infections are quite easy to catch, and they propagate faster if there is a lot of moisture in the air and/or on the plant itself. And water droplets on the leaves themselves may cause sunburn if the plant is in direct sunlight – the droplet will act like a small magnifying glass and heat that portion of the leaf. 

The best way to water any plant is to water the ground, right at the stalks. Do your best to leave the leaves and flowers dry. 

Don’t let the mint plant stay in direct sunlight

All plants need sunlight, including mint. But fragile, tender herbs like mint, basil, parsley, dill, and other similar herbs really don’t do well in bright, direct sunlight. So keep your mint in a shade but bright spot, like on a porch that is covered and only gets sunlight in the second part of the day. By the time the sunlight hits the plant it won’t be a bright and hot to damage the plant.  

This is especially true if you live somewhere very hot, or if you’re growing your mint on a windowsill facing S-SW-W where the sunlight is very hot. If that is the case, take the mint away from the windowsill, and either place it on a N-NW window or just keep it close to the window but not in direct light. 

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