How to minimize and prevent mold growth on decks?

mold growth on decks

A wooden deck enhances the beauty of the patio of your house but the growth of molds can be quite a put-off. Greenish and blackish molds make the deck look unclean and unglamorous. It is a natural phenomenon and grows when wood comes in contact with temperature, air, water, and food source- all of which be found in an uncovered deck. However, there is nothing to lose heart because such decks can be cleaned and fixed with a bit of effort. The growth of green algae and mold can be prevented even if there is no permanent way of completely stopping it altogether. If you have invested in a composite deck board with a cap then your wooden deck can be protected to an extent but you will not find a complete assurance. 

Why molds?

Molds usually grow from excess usage of fertilizer, airborne pollens, and sometimes even leaf litter. These are airborne and hence can find their way almost anywhere. The presence of air, water, temperature, and source of food paves the way for the growth of the mold completely. The presence of molds in the area surrounding the house makes it easier for them to grow. The spores gradually bloom in the presence of the feasible conditions and create blackish spots on the wooden surface of the deck. 

How to stop mold growth?

The absence of dirt and a good cleaning regime can take care of most molds. Ideally, the deck should be cleaned at least twice a year if not more. This is, of course, depending on the region where you are settled because some parts which are moist than the others facilitate the growth of molds even more. Therefore, in some places, the cleaning process has to be repeated more than twice to reduce the growth of molds. Create a cleaning schedule once the deck has been cleaned thoroughly so that it can be maintained. 

Is power washing a way out?

Power washing is good for cleaning the deck, yes, but if it has molds on it then, no! The pressure that is applied with the water jet actually forces the mold particles to further penetrate inside the wooden boards and allow it to fester. Therefore, it should be avoided unless the user is extremely careful and aware of how to tackle the cleaning process. If you are actually struggling with the mold situation then it is best avoided. 

The way out

A thorough cleaning is the best method for cleaning the deck. Before you start cleaning it, remove all the plant pots, furnishings, and the barbeque grills. Sweep away using a regular broom and especially around the area where the railings touch the deck. The dirt present in the corners should be removed immediately. You can use a leaf blower for the purpose. Washing the dirt with a garden hose is a good idea or you can even use a power washer. But you have to keep in mind that using a hose might make the deck apparently look clean but the mold is hidden deep inside. It will also grow back quite fast once it gets suitable conditions. 

Using a deck cleaner

A good quality deck cleaner is essential if you are wondering how to remove green algae from wood deck. The best thing about these cleaners is that they help in loosening all the dirt and debris from the deck. Pick one that is best suited for removing green algae. An all-purpose cleaner will not be useful in this case. The best cleaners use oxygenated bleach instead of chlorine bleach which is unlikely to damage your precious wooden deck. 

You will need to wet the deck and then use the cleaner on it. As the pores of the wood get filled by water the cleaning liquid is unable to get inside. Therefore, this means the cleaning remains on the top and does not affect the wood. Washing away the same also becomes very easy because you have to rinse less of it. The cleaning liquid should be used in lukewarm water so that it gets activated easily.  If the temperature is excessive then also the activation of the product will be faster and the effectiveness will be reduced. Coldwater can also be used if lukewarm water is unavailable. However, the time required will be a little more than the necessary one. 

Just spread the liquid on the wooden deck and let it kill the algae. The wood should be kept wet so that it does not dry out fast. This will make the solution ineffective. Use a wood brightener once the surface has been cleaned completely. It makes the surface look bright and as good as new. 


A house with a nice and clean wooden deck looks impeccable. So, if you have been wondering how to remove green algae from wood deck read the article and gets started. 

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