Affiliate disclosure: We may earn a commission if you make a purchase through these links at no extra cost to you. For more info, visit our disclosure page.

What To Do If Your Terrarium Moss Is Turning Brown Or Yellow

Moss is a staple plant for any terrarium. But what if your staple plant starts turning shades of brown or yellow?

Browning or yellowing moss is usually a sign of either too little, or too much water. Gently touch your moss to see if it’s wet or dry. If it’s dry, mist it with some distilled water. If it’s wet, the brown spots are probably rotted and should be removed. Otherwise, it could be a symptom of using tap water rather than distilled water or rainwater.

Moss generally live one to two years and are green year round. So if you’re seeing browning or yellowing, that’s a clear sign that something needs to change.

Causes of browning/yellowing

Before we get into taking action, we want to make sure that we identify the root cause of why your moss turned yellow or brown. 

There are a few items you might want to check first to find that out:

  • Touch your moss to feel if it’s very dry or very wet
  • Observe the lighting conditions of your terrarium
  • Identify the species of moss you have

When you’re feeling your moss, you’re basically checking if it’s had too much water or needs more water. If it’s dry, it needs more. If it’s wet, it’s had too much. Pretty straightforward, but is probably the most likely cause of the undesirable color change.

The other thing you’ll want to do is to check the lighting conditions. Moss generally don’t prefer to be in direct sunlight, but would rather be in the shade, receiving indirect sunlight.

If your moss is receiving sunlight directly, the sunlight’s going to quickly dry it out. This is exacerbated especially in open terrariums, where the humidity is at a lower level and the light intensity is slightly higher without a glass or plastic container providing a little bit of protection.

The last thing you’ll want to check is the species of moss that you have in your terrarium.

There are over 20,000 species of moss. While most of them prefer to grow in humid, shaded areas, there are exceptions. 

Scotch moss, for example, is a species that prefers to receive direct sunlight and does not thrive in humidity.

As a sanity check, it may be helpful to verify which species of moss you have so you don’t run into any unexpected surprises about their preferred living conditions. If you’re not sure, you can try posting a picture on some forums for help or just browsing moss species to find the closest match to what you have.

By the way, if you want to hear my tips for growing terrarium moss successfully, check out my article on growing terrarium moss that thrives.

How to revive your moss

So you have brown moss. Now what?

Once you’ve diagnosed the probable cause of the browning, it should be pretty straightforward to address it.

If you feel that your moss is really dry, just spray it with a little bit of water to freshen it up. You might also consider giving it a quick 15 to 30 minute soak and letting it dry before adding it back to your terrarium.

If you found that your brown moss is really wet to the touch, it’s probably overwatered. If you see water pooling at the bottom of your terrarium, that’s another sign of overwatering.

In this case, the brown spots are likely rotted areas. You might be able to detect a rotting smell coming from your moss. You’ll want to remove those to limit the spread of the rotting area.

You’ll also want to wipe off the condensation on the walls of your terrarium container and let it air out for a while. 

If you touch the moss and it didn’t seem too wet or too dry, it could be the lighting. If you’ve been putting your terrarium right next to a window, you may want to try moving it away from the window towards the center of the room for a few days to see if that helps.

Alternatively, you could give it a couple hours of sun per day and then move it to a shaded area. Or if you’re feeling like spending some money or have a light lamp lying around, you can try controlling the intensity and duration of light being shined on your terrarium.

The final thing you’ll want to do is to switch to distilled water if you’ve been using tap water. Tap water has minerals and chlorine that may be harmful to your plants.

Go out and buy a gallon of distilled water on Amazon or your grocery store and start using that to water your moss. You can probably get a few gallons of distilled water for just a few bucks.

If you’ve tried all of that and your moss still hasn’t been revived, there’s a chance that your moss is dead. If this is the case, you might smell something rotten and feel that the moss is falling apart to the touch. At this point, there’s nothing you can do besides throw it out and get new moss.

I want to be careful about saying that though because I don’t want you to think that if your moss is brown that means it’s dead. In many cases, even completely brown moss can be revived with a little bit of water and sunlight. 

It’s possible that dried moss is just in a dormant state just waiting for a little bit of water to wake up. It may just take a little bit of time to see the changes. 

Just give it a quick soak and see how it’s doing in a few days before throwing it out.

However, if you’re buying dried moss online, it’s very possible that they’ve added preservatives or added colors to it for decorative use. This type of moss will never return to its thriving green color no matter how much care and watering you give it.

How to keep your moss green year round

Moss should be relatively low maintenance plants that will last you for 1 to 2 years. But that doesn’t mean you can just neglect them and still expect to find them green year-round.

There’s a few things you can do to provide the optimal living conditions for your moss. 

The checklist shown in the first section doesn’t have to be a last resort. You don’t have to wait for your moss to turn yellow or brown before taking action. It can also be a preventative measure or a regular checkup on the health of your terrarium.

It’s probably advisable to go through the checklist once every one or two weeks primarily to check on the water levels. 

If your moss is in an open terrarium, you should be watering your moss once every few days especially if it’s hot in your area.

Aside from that, you may want to consider moving your plants to a close terrarium if you’re using an open terrarium.

Closed terrariums generally provide a better environment for moss. They keep the humidity levels pretty consistent and offer more protection from direct sunlight. 

If your moss is in a closed container, a watering once every one or two weeks should be fine. Just open it up and spray a mist evenly around the whole container and wipe down the sides once you’re done.

But first you will also want to check the condensation levels on your container throughout the day. No condensation means it’s time for watering. If you see condensation all day or water pooling in the bottom, that’s a sign that there’s too much water in your terrarium.

With proper care and regular checkups, I believe you’ll find yourself with green, happy terrarium moss year round.