Moss Signals the End of Winter is Near
Temperature is about the only limit on my outdoor gardening experience in the winter. As long as the temperature is above 30 degrees F (0 degrees C), I have no problem finding a garden task to perform. This is my hobby and passion so it has never been anything less than enjoyable. I go out of my way to drink a couple of beers at the end of each day admiring my gardens while at the same time seeking ways to improve the appeal. There is never a lack of puttering tasks. Only freezing temperatures keep me inside.
February is when I watch the thermometer so that I can sneak outside and begin picking up sticks. The first hints that winter won’t continue for long usually happen about this time. These are the first few days in a row when temperatures are moderate. The sun is strong enough to begin thawing the soil enough for the moss and lichen to begin growing. This year we had an unusual stretch of a week about halfway through the middle of January with above average temperatures. We are in the low to mid 40s during the day and only down to the mid to upper 20s at night. I have no complaints being a couple of weeks ahead of schedule . . . as long as this is not an omen for a brutally hot summer.
What is Moss?
You will have noticed that I mentioned lichen along with moss as the first two “plants” that begin growing. Lichen grows during similar environmental times of the year. Lichen is not related to moss. Nor is it a plant. It is actually a symbiotic relationship between bacteria and/or algae and the mycorrhizal fungus mat which houses these organisms.
Moss is, as near as anyone can hypothesize, an ancient plant form. It is not a true plant. There are many biological and genetic qualities that we can’t explore today. Because moss is so delicate there are few fossilized records to definitively establish when moss first began to grow. There are many who believe that moss has been around a good 450 million years. Some go so far as to suggest the when moss first colonized the surface of the world it quickly became a key player is reducing the carbon dioxide concentration in the atmosphere which soon encouraged large frozen areas especially at the poles. Taking carbon out of the atmosphere allowed the planet to cool.
These beliefs are plausible. Moss has ancient component structures that are not found in true plants. The first of these is that the stems do not transport water or nutrients. The vascular system of plants allows all cells to be interconnected. Some transport water. Others transport excess food from the leaf to the root. The stem of the moss appears to only act as the scaffolding for the teeny weenie leaves.
The next important difference is the roots. In fact these are not even true roots. They are a rhizome structure that does not transport water or basic minerals to the rest of the plant. These structures appear to only anchor the moss to the soil. Though if one attempts to transplant moss these should be left attached and not sliced off.
The little bumpy ridges you can barely discern on the small stems are actually leaves. They are quite small. They attach directly to the stem. One of the important aspects of these leaves is that they are only 1 cell thick. A hosta leaf has a 3 cell thickness. Another aspect of moss leaves is their superb ability to absorb water and necessary nutrients directly from the rain and air. Because the stems don’t transport water and nutrients the leaves have to provide for themselves.
This is one of the reasons you find moss growing everywhere. The leaf is able to absorb directly the few necessary raw products without help. This means that moss is able to grow in low fertile habitats. Increasing humus and other organic components is one way to limit moss growth. The fertile additives are probably not the primary reason it discourages moss growth. It is the result of the ability of organic rich soil to wick water away. Moss requires moist soil to thrive. A soil that dries out quickly is a habitat moss does not like.
Moisture is the primary reason moss chooses to grow in an area. Low evaporation rates happen in smaller places like the cracks in the brick sidewalk, woodland areas near streams and other common out of the way quiet niches. I see plenty of moss in shallow water on the top of my garden in the late winter. A warm day may thaw the surface but the soil is still frozen down as much as a foot for my area of the country. The water just can’t be absorbed. This is another reason we all notice moss late winter. The shallow water is welcome.
The temperature is also another major factor for luxurious growth. Moss is completely cold hardy. Water and humidity levels are quite high as the soil begins to thas. The soil surface dries out really fast in warm weather. Moss will quickly go into dormancy when the soil dries out. Porous soils and warm weather are the greatest restrictions on moss growth. Shaded woodland locations are prized moss locations. All of these areas stay cool longer into the season.
These stagnant areas provide the last bit of information that encourages moss growth. Low fertility is just one aspect. The other more important reason is that these areas tend to be lower Ph. Moss tends to like these low Ph areas. Increasing soil Ph in fact is a controlling factor. It is especially important to look at moss growing in with your grass. This is a sure sign that you should add some ground limestone. Limestone provides both calcium for the grass but also raises the soil Ph.
Control or Encourage
Understanding the growth requirements of plants is knowledge one should learn for any “weed”. They reliably tell me what is right or wrong for a garden bed location and it doesn’t require a soil analysis. We have already found several aspects about moss that a gardener can use to either discourage or encourage growth as you desire. I use all the growth characteristics to help me understand how to manage a bed.
I am going to enjoy the large areas in my woods that have moss. They only look good until the daffodils are blooming. I appreciate these natural sites until then. I will soon miss them when they go dormant in the hot dry summer. I don’t fear. They are able to be dormant for considerable time. There have been some experiments that show just how long a moss can be dormant which is incredibly long. I notice some regenerating in the fall though most wait until the spring.
On the chance you want to encourage moss all you have to do is to create the habitat moss desires. Naturally distributed spores traveling with the wind will find your location. Transplanting moss is difficult. It is far easier to keep the area moist, cool, and shaded with perhaps lower Ph and let nature do the colonizing. Most have great success spraying with a molasses and water mixture. A course rock exterior is better than a smooth surface. This is how most encourage moss on new stone walls.
Adding a bit of iron and/or limestone to your grass fertilizer is the best for reducing moss. The grass will appreciate the change too. When you see small irregular patches of grass with moss in between you will know you have a mineral issue. These are precisely the minerals that are missing. Also, be sure to increase light by removing excess shading. This will increase air movement too. If water seems to take forever to drain from a location you will want to consider providing some drainage. A soil surface that dries quickly is an important preventative.
There are chemicals one can use for control but most are not good for surrounding plants. Some take professional applications. Even one of the more effective and least hazardous can sometimes take several applications. Being the green gardener means making a habitat unappealing for the trouble plant. You may decide that moss does make an appealing addition to the garden. Either way, moss is important as a herald for beauty, soil health and most importantly growth activity in the harshest time of the year. That alone is why I love moss. There will always be a need for moss in my gardens.