Should You Water Moss With Tap Water?


While moss tends to need different care than other plants, one thing that remains common is the need for water, especially in drier weather. Moss absorbs water through its entire body, which makes it very susceptible to injury via mineral concentration. This might leave you wondering if it’s safe to water moss with tap water. 

You should not water moss with tap water because most tap water is treated with chlorine which can hurt the moss. Tap water may also be treated with fluoride or have a high concentration of salts like calcium which burn the moss. Instead, use distilled water or rainwater for your moss. 

Moss can survive prolonged periods of dehydration, but to keep it green and healthy, you must water it regularly. This article explains why tap water is bad for moss, the type of water to use, and how to water moss correctly to keep it alive, so read on!

Why Is Tap Water Bad for Moss?

Tap water is commonly available and used for watering plants. Most plants should be okay with tap water, but in the long run, it is better to rely on rainwater or tap water that’s been treated to be more like rainwater. 

In my other article, you can learn more about making tap water like rainwater: How to Make Tap Water More Like Rain Water?

Tap water is bad for moss and other plants because it tends to be treated with chlorine and chloramines. Chlorine is a disinfectant to make water safe for human consumption. 

While the concentration of chlorine isn’t high enough to kill a plant in one watering, over time, the chlorine can build up and affect the plants, especially plants like moss that absorb water. In fact, chlorine is sometimes used as a cleaning agent to remove algae and moss from tiles. 

Apart from chlorine and chloramines, some regions use fluoride in their water, which can lead to browning in moss. A similar effect is observed when hard tap water, i.e., tap water with a high concentration of salts and minerals, is used to water moss. 

Moss will survive this as most varieties can endure long periods of desiccation, but they will be an unsightly brown color. The easiest way to avoid this is to water moss with more or less ‘pure‘ water without chemicals like chlorine, fluoride, or extremely high concentrations of minerals. 

Tap water is especially bad for moss that is young and yet to be fully established. An established patch of moss can weather injury through dehydration and ‘burning’ more easily than young or smaller patches or balls of moss. 

What Kind of Water Does Moss Like? 

We know that moss is sensitive to tap water and its components, but that doesn’t mean that caring for moss has to be a chore. 

Moss likes rainwater best as it can obtain both water and nutrients from it. Moss also likes filtered or distilled water, but you may have to supplement the distilled water with nutrients if you want to encourage growth. You can also treat your tap water to make it better for moss. 

Rainwater harvesting is an efficient and effective way of using available water, especially since all plants benefit from rainwater, not just moss. Rainwater is pure but still contains some concentration of minerals, and more importantly, nitrates, that supply nitrogen to plants.

Nitrogen is essential for plant development, as it makes amino acids and other proteins that lead to growth, and rainwater is an excellent source of this nutrient. 

If you live in a region that doesn’t experience a lot of rainfall, you can filter your water to remove fluorides and minerals by using an activated carbon filter. Another option for water that’s heavy in fluorides is to use a membrane-based filtration system.

While an activated charcoal system is one of the easiest ways to filter your water, you can avoid a lot of expense by simply setting your tap water out in the sun or boiling it. The heat encourages the chlorine to dissipate. However, this method is ineffective when it comes to fluoride. 

You can learn more about the advantages and disadvantages of treating tap water in my article about boiling tap water before watering plants: Should You Always Boil Tap Water Before Watering Plants?

Distilled water is also an option, but remember that distilled water involves purifying the water through a process of evaporation and condensation that removes all minerals. Moss receives its nutrients through water and air, so ensure that you occasionally mist it with extremely diluted organic fertilizers like manure or compost tea if you’re using distilled water. 

When To Water Your Moss

Moss relies on water for hydration, nutrients, and reproduction, so naturally, it needs a lot of water to stay green and healthy. The best time to water your moss is in the early morning, as this ensures maximum water absorption and utilization. 

If you water your moss after the sun is high in the sky, most of the water will evaporate before your moss can absorb it. However, when you water them early in the morning, they can take advantage of the sun’s heat to use the absorbed water and sunlight for photosynthesis.

Keep your moss wet by misting it regularly, about once or twice a week, especially when the weather is dry. However, if you experience rainfall regularly, you won’t need to water more than once every few weeks – just enough to keep the moss green and damp. 

If you’ve just harvested and placed your moss, you may need to water it more frequently as it adjusts to its new environment. Mist using a hose with a fine misting head every day, up to twice a day, taking care not to drown the moss. 

Can Moss Be Overwatered? 

Moss can survive various weather conditions – from scorching and dry weather to extremely cold temperatures, so they’re reasonably hardy plants. Underwatering may cause moss to go dormant, but can it be overwatered?

Moss can be overwatered, especially if you drench and soak them when watering instead of offering a gentle misting. Overwatering can cause moss to get soggy and eventually suffocate and rot away. 

Remember that moss doesn’t have roots and doesn’t grow on very much soil, so there’s nowhere for the excess water to go. If you overwater your moss, the extra water will suffocate the cells. You’ll notice the moss browning, as it would when desiccated. 

An easy way to identify if your moss is underwatered or overwatered is to touch the moss when you notice browning. Underwatered moss will feel dry and crumbly, while overwatered moss will feel like a sodden sponge

Tips for Keeping Moss Alive

Keeping moss alive shouldn’t be a chore. In fact, the resilience of this plant means that you can keep it in a wide variety of conditions, and it will survive. Nevertheless, here are some tips to take care of your moss: 

  • Keep your moss damp. Mist the moss whenever you see it drying out or once every few weeks if there’s no rainfall. Damp conditions encourage moss growth, while dry conditions prohibit it. 
  • Ensure the surface it grows on is damp. Moss typically grows on bark, stone, or similar surfaces, which must remain damp to ensure the moss lives. 
  • Use rainwater. Chlorinated tap water can lead to toxicity and burning in your moss. Use collected rainwater or filtered tap water instead. 
  • Clean the moss. Moss does best when it is left unobstructed, so clean away any leaves or other garden bits that may be covering it. Be gentle, as the moss doesn’t have roots and may be pulled off its growing surface easily. 
  • Ensure it’s in a shaded area. Moss enjoys sunlight but not direct sunlight. It grows best in slightly damp, shaded areas, which hold onto moisture easily. Moss also prefers cooler temperatures, which are easier to find in shady areas. 

Final Thoughts

Moss should not be watered with tap water unless the tap water has been treated by leaving it out in the sun, boiling it, or by using a filtration system. Ideally, use collected rainwater to water your moss in the early morning to supply it with the nutrients it needs to grow.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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