When And How To Water Moss

When to water moss depends if it is recently transplanted or already established. It also depends if it is an Acrocarpous moss or a Pleurocarpous moss.

Below is a guide with instructions on when and how to water mosses.

How To Water Moss

Watering moss using a hose and fine spray head is the most economical and accurate method for irrigation. Irrigation systems can also be used if they have the proper fine spray heads and are allowed to be scheduled.

This usually requires a dedicated zone and programming. Hose end sprinklers are another possibility and can even be operated by a battery-powered programable timer that attaches directly to the spigot.

If your water supply is from a well or a municipal system, you may want to have your water tested for chloramine or sulfur. High levels of each can harm moss growth.

You can also just water over two months to see if there are any negative effects. Using collected rainwater will provide the best results over any other water source.

When To Water Moss

Since mosses must have sunlight to metabolize, the best time of day to water is early in the morning. Avoid watering your mosses close to dusk, so they have time to accumulate net gains in their energy production.

When to water your moss depends if the moss is established or recently transplanted; it all depends on the type of moss being transplanted. Acrocarp moss has different requirements than pleurocarp moss. We later explain the difference between these mosses and the different watering techniques.

Transplanted Moss

To help with the establishment, the wisdom is to provide water to the moss after the transplant frequently, but how often and for how long is the question and highly depends on the situation or the type of moss.

Transplanted mosses to a new location need time for the moss to acclimate and become established. Acclimation is the process of the moss adjusting to the new location’s elements such as altitude, sunlight, water, wind, and the substrate the moss will be growing on.

Each of these will affect different mosses to greater or lesser degrees depending on the species, their growth rate, and habit, which may increase or decrease depending on those changes.

Established Moss

Establishment occurs after acclimation to environmental differences and when new rhizoids have re-attached the colony to its new substrate.

Acrocarpous Mosses

Acrocarpous mosses grow slower and will not tolerate constant moisture for longer than 2 or 3 months; if water persists, they will begin to rot and eventually fail.

They can benefit from a rainy season or regular irrigation once a year, but after that, they will need regular dry spells.

If you are unsure whether your moss is an acrocarp, read this article and monitor its condition carefully. Look for signs of the moss turning dark and if there is a reduction in height. These signs indicate it’s getting too much water, and a break from frequent moisture is needed.

Watering Chart

Below is a helpful watering chart for establishing Acrocarp mosses.

• Months 1 & 2: water daily for up to two months to promote growth.
• Month 3: Water every three days for one month.
• Month 4: Water once a week for one month.
• Month 5: Water twice a month until the area is fully covered in moss.

After that, water only when rain has been absent for three weeks or more.

Pleurocarpous Mosses

Pleurocarpous mosses can be watered daily and up to 6 times daily in small volumes. This consistent moisture will keep pleurocarps growing year round if the conditions are right.

The caveat for a frequent watering schedule is to be careful and not create the conditions for problems to form. Too much volume can create soggy conditions that may cause root rot for other plants. Be sure the delivery and timing of the water moistens the moss but does not soak the soil.

Molds, mildews, and fungus can also cause problems for Pleurocarp mosses. When temperatures rise above 75 degrees, constant moisture can cause the development of molds, mildews, or fungus.

These may grow on the bare soils surrounding the mosses or on the moss itself. If any of these problems occur, allow the area to dry out completely and resume with a lower volume of water.

After pleurocarpous mosses have filled in and become a thick and lush growth, watering can be reduced over time, allowing rain to provide for the moss’s watering needs.

If you are in an area with low rainfall levels, you may need to supplement during drought. Avoid creating a wet then dry cycle multiple times a day. The effect of drying out several times a day can produce a net loss in energy production.

Rainwater vs. Tapwater

We recommend using rainwater for the best results, you can also age your tap water to reduce the chloramines.

Use filtered, distilled or rainwater where you can. Chlorine and chloramine are hard on moss, and tap water differs city to city. Established moss on open ground copes with tap water better than a new planting or anything under glass, but if you are watering moss that is still establishing, or moss in a terrarium, it is worth standing the water overnight or collecting rain.

TIP: A misting head on the hose gives finer, more even coverage than a jet, and moss wants little and often rather than a drenching.

Watering Techniques

We have achieved superior results in vitality with higher quality water sources like collected rainwater, so water chemistry does matter. For optimum results, pay attention to volume, frequency, and time of day.

Drenching can lead to problems, frequent misting is better. Watering in the morning or afternoon is better than in the evening. Depending on the species your growing, regular drying out may be required for long-term health.

Avoid creating a constant wet then dry cycle over hot summer days.  It’s better to keep moist all day than dry all day, this avoids having the moss go into dormancy multiple times in a 24-hour period which uses as much energy as it produces, resulting in a net loss for the moss growth.

Creating A Moss Lawn

We have been sharing information about moss-understanding growth rates, preparing soils, how-to collect mosses, and this post about watering moss. 

These series are steps in the process of creating a moss lawn. Each step leads up to presenting a thorough understanding of our ultimate goal of writing a how-to on creating a moss lawn.

The first step was Understanding Growth Rates.

The second step was Preparing Soils for Moss

The third step was How to Collect Moss.

Frequently Asked Questions

Related reading: Earthworm castings on moss

Pending review by Olivia Milner, practitioner-scientist with a background in sustainability and education.