Growing Mint Indoors: Must-Know Tips for Growing Mint Inside

Robust and wonderfully fragrant, mint plants thrive indoors as much as they do outdoors. Mint is an excellent used in sweet and savory dishes, and it is therapeutic, as well.

This easy to grow herb is super adaptable and finds ways to flourish wherever it is planted. If you’ve ever planted it outdoors, you know what I’m talking about! It is well-known for taking over garden beds in its enthusiasm to grow.

Mint’s vigor is what makes it such an excellent choice for growing indoors. It will expand to fit any pot you plant it in and grow vivaciously.

Added bonus: mint is widely considered a repellant for many insects including fleas, roaches, ands, and even spiders. (Learn more about plants that repel spiders.)

Types of mint

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First, the fun part – what type of mint do you want to grow? There are so many types beyond the standard peppermint. Have you ever tried chocolate mint or orange mint? A cup of hot cocoa with a few orange mint leaves is divine.

How to grow mint inside

Mint is extremely easy to grow indoors and out.

Mint plants will grow for many years, but they are best replaced or repotted every three years. Take a cutting from the old plant to start a new one – no need to get seeds or buy a new plant!

We’re going to take a look at growing mint from seed indoors, growing mint from cutting indoors, then general mint light, soil, water, and fertilizer requirements.

How to grow mint indoors from seed

1. Plant mint seeds 1/4” deep in a wide container filled with a well-draining seed starting mix. Put several seeds in one pot – they’re super small and hard to plant separately.
   • Make sure the pot has drainage holes, or else the roots may rot, and the mint will die.
   • Use a wider container as opposed to a deep one because it facilitates the mint plant’s roots better. Mint is a sprawler that likes to spread.
2. After planting, water the soil well, but gently. Using a mister can help you avoid moving the small seeds.
3. Place the container in a warm location.
4. Mist the soil regularly to keep it moist, but not soggy.
5. Mint seeds germinate in 10-15 days.
6. Once the seeds sprout, move the container to its permanent location.
7. Water regularly, about once per week, letting the water drain thoroughly to prevent soggy roots.
8. As the seedlings grow, thin them, if desired. It’s best to have just 1-2 plants per pot since they will grow readily and fill the pot easily.

In the image below, you can see many mint seedlings in a pot. These seedlings need to be thinned out. To avoid disrupting the plants you do want to keep, pinch or cut unwanted seedlings off at soil level.

Seed starting mix is a sterile medium that’s best for starting seeds. Non-sterile grow mediums, like your garden soil or regular potting soil, may contain various mold and fungi that can damage seedlings.

A common seedling problem is “damping off.” Damping off is caused by various mold and fungi that prefer cool, wet conditions. It can kill seedlings or severely stunt their growth. (source)

If you don’t have seed starting mix, you can bake your potting soil to sterilize it. Place it in a rimmed baking sheet in a 200ºF oven and bake until the internal temperature reaches 180ºF. This typically takes 30-60 minutes. (It also makes your home smell like cooked dirt, which isn’t all that pleasant.)

How to grow mint indoors from cuttings

Stem cuttings are the easiest and quickest way to grow mint. You can easily replicate plants you already have or get a cutting from a friend who already has a mint plant. Because mint cross-pollinates easily, it’s better to cut off any flowers that form and use propagation instead of saving mint seeds.

1. Using sharp scissors, cut a 6” piece off the stem just below a node (the intersection between the stem and branching off section). Make sure to get fresh growth, not hard, old, woody growth.
2. Carefully remove the leaves from the lower 2” of the stem.
3. Place the stem in a small vase or jar of water and place it on a sunny windowsill. If you don’t have a windowsill, or if you have kids/pets that might knock it over (I do), consider using some inexpensive LED grow lights.
4. Change the water out daily.
5. Let the stem grow in the water until it forms 2-3” roots. Honestly, I’ve planted mint with shorter roots and had them do fine, but it’s better to have longer roots if possible.
6. Once there are sufficient roots, plant the stem in a wide pot with good quality well-draining potting soil. Be patient – this can take a couple of weeks.
   • Use a container with drainage holes, and one that is wide instead of deep. Mint roots prefer wide, shallow growing containers.

Mint does not typically need a rooting hormone, but using a dusting of rooting hormone on your mint cutting can speed up the rooting process.

If having a jar of water sitting around in your window is unappealing, you can stick mint cuttings into Root Riot cubes or a similar hydroponic grow medium. You do not need a hydroponic system to start plants in these cubes. Place the cubes in a seed starting tray with cells and provide plenty of moisture. Root Riot cubes are my favorite way to propagate mint and start seedlings.

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Growing mint hydroponically indoors

Hydroponics, and aquaponics, are great ways to grow mint indoors if you’re interested in getting a little bit more “fancy” with your growing.

The biggest “problem” with growing mint hydroponically is that it will send out runners and try to invade other plants. You have to remove the pod from the system from time to time and cut away “below ground” runners. (Read more about trimming runners in this post on how to pick mint.)

The easiest, all in one system to begin indoor hydroponics with is an AeroGarden. It has built-in lights and a timer so it’s very convenient to use. You can grow herbs, greens, and even some vegetables in larger AeroGardens.

The AeroGarden 360 is ideal for growing kitchen herbs, and even comes with a seed pod for mint.

I used an older AeroGarden model for several years to grow lettuces and kitchen herbs. It is easy to use, but the light is quite bright so you need to have a place where it won’t bother you while turned on.

Here you can see a few lettuce and herb seedlings under the light. Most AeroGarden systems have an adjustable light so you can keep the light at the correct distance from your plants. This is in contrast to some countertop grow systems that do not have an adjustable light. Avoid these systems because they can create leggy, weak plants.

For a larger grow system, my top pick is the LettuceGrow Farmstand. I personally own one that grows outdoors in the summer and indoors in winter. If you decide to order one, be sure to use the code FRIEND-MMT9 for $50 off. In the picture below, taken from this post on how to harvest mint, you can see spearmint from my Farmstand in its grow cup:

The peppermint below came from a cutting I rooted indoors in RootRiot cubes before placing it in the FarmStand.

How to care for mint plants indoors

Let’s take a look at mint’s light and water requirements to ensure your plants stay healthy and strong:

Mint indoor light requirements

To grow mint successfully indoors, choose a location where it will get a lot of indirect sunlight. East-facing windows are best. This is another great thing about mint; it doesn’t need the prime south-facing window location that other plants require.

If you have children or cats, placing plants in windowsills can be a gamble. I have a toddler and a cat, so I grow my indoor mint under these inexpensive LED grow lights.

I place the clip-on grow lights on a shelf and position the lights just a few inches above my mint. Bonus: I also use these lights to start seedlings for transplanting in my garden and for my LettuceGrow Farmstand hydroponic grow tower. (If you decide to order one, make sure to use code FRIEND-MMT9 for $50 off!)

Mint water requirements

Mint likes moist, but not soggy soil. Touch the top of the soil, and if it is dry, water the plant. This is usually about once a week indoors, but your plants may need more or less frequent watering depending on conditions. Mint does need consistent moisture to grow, so make sure not to let your soil dry out.

Fertilizing mint

There is no need to fertilize mint. In fact, it often negatively impacts the flavor if it is over-fertilized.

If you’re using a hydroponic system, make sure to add nutrients as described by your particular system.

Ideal temperature for mint

Mint prefers cooler weather, but can tolerate warmer temperatures. too. If you’re comfortable in your house, your mint should be fine. Keep the plants away from any drafts, and do not place them near heat radiators.

Outdoors, mint is a perennial herb that dies back in winter and regrows in the spring. You can bring potted outdoor mint inside for the winter to keep it producing. Fresh mint tea is a wonderful pick me up on a cold winter day!

Indoor mint growing tips:

• Water regularly. Mark it in your calendar to check your plant once a week. Do not let the soil surface dry out. Water the plant thoroughly, allowing the water to flow out of the bottom of the container. Drain off any excess water.
• Mint plants will grow towards the closest source of light. This causes the stems to bend, become spindly, and grow unevenly. Rotate the plant every time you water to keep it growing proportionally. It will be healthier this way.
• Avoid adding fertilizer. Mint plants don’t need it; they grow robustly enough on their own.
• Pinch off flower buds to encourage the plant to grow more foliage and produce longer.
• Harvest or prune the plant regularly to prevent it from getting leggy and maintain a bushier appearance.

Mint is ready to be harvested anytime after the plant reaches 6-8” high, or has produced multiples of leaves.

For a detailed look at harvesting mint, complete with pictures showing you exactly where to cut to ensure your plant grows back healthy and strong, please see this guide on how to harvest and preserve mint.

Mint is easy to preserve and save for later. It’s delicious for herbal teas and you can even make your own homemade mint extract!