Can Sand Mulch Catch Fire? What You Should Know


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The granular material composed of finely divided rock and mineral particles makes beaches pleasant places to hang out. These are the components of glass that are none other than ‘’Sand”.

Sand cannot catch fire. Sand comprises mainly of oxidized silica and melts at approximately 1700°C (3090°F). For this reason, sand makes an excellent agent for extinguishing fires. When subjected to bush fires and radiant heat from the sun, mulched sand will remain unscorched.

Did you wonder that sand can catch fire and are not beneficial for growing plants, and can be reactive? And did you know the importance of hot sand?

Get ready! Because we will address each question in this article, we will also suggest some plants that can grow in sand.

sand in gardening

Is Sand Flammable?

The absence of unoxidized silicon in sand to react with Oxygen makes it flammable.

It doesn’t mean that one cannot burn sand as anything heated enough will be broken down into its constituent elements.

Following are the two elements that are found in sand:

  1. Silica (SIO2- Silicon Dioxide)
  2.  Oxygen

Furthermore, erosion has created most sands over millions and millions of years in the sea and shores. Some minerals like selenite, gypsum, and calcium sulfate are very rare but can also foam sand.

Silica is flammable, not explosive, and non-explosive. 

When sand is burnt, silicon dioxide is in the air as it bonds to oxygen molecules, so sand is already ‘’Burned’’ and won’t catch fire if you set fire on it. 

This is mainly due to the absence of unoxidized silicon in the sand.

Besides this, it is not even combustible because it is itself a product of combustion as it has already oxidized to the highest level, and therefore it won’t burn.

Although sand is not flammable, this doesn’t mean one couldn’t burn it at extremely high temperatures. 

Anything can be burnt into its constituent elements, and Silicon produced at this heat can be flammable. However, such things do not occur under ordinary conditions.

Is Sand Reactive?

When it comes to the reactivity of sand, two types of sand need to be discussed.

  1. Silica Sand:

Quartz sand, white sand, or industrial sand comprises two main elements: Silica and Oxygen. 

Specifically, Silica sand is made up of Silicon Dioxide (SIO2).

The common one is Quartz which is chemically inert and a relatively very hard material.

  1. Regular sand:

These brown and construction sand always contain some silica, but less than 95%. 

However, the concrete applications can contain up to 80% SIO2 and varying amounts of Iron, Carbonate, Potassium, and other trace elements or minerals. Hence, these impurities are responsible for making regular sand more chemically reactive.

Is Sand Toxic to Plants?

If one wants to make a good soil mix, then sand is an essential component of a good soil mix. However, sand contains contents that make it difficult for soil to retain nutrients and water.

There is also beach sand that contains high salt levels, and it is difficult to retain water and nutrients for the plants to grow healthy. 

Some plants can withstand drying cycles easily and prefer a soil environment that does not retain excessive moisture.

Following are the plants which can be grown on sand:

  • Cacti
  • Sedum
  • Lamb’s ears
  • Purple coneflower
  • Coreopsis

In addition to this, sand has disadvantages as a growth medium. Still, luckily it exists in a pure state, and there are some silt particles, which increase its ability to hold water and retain nutrients.

Besides this, natural sand with silt and a little organic matter is best for growing plants. This type of soil is called either sandy loam or loamy sand.

Sand adds air space to a potting mix. Builder’s sand, or coarse sand, is best. Avoid plaster and fine sands; they create a dense mix. 

Because it is heavier than other ingredients, sand is suitable for top-heavy plants that might tip over.

When water can’t drain, the roots suffocate, and the plant dies. A mixture of compost or peat and horticultural sand is an ideal environment.

Will Hot Sand Prevent Gnats?

The sand, which one can amend with the soil for drainage, also helps prevent fungus gnats.

The coarser grain is better, and beach sand and like are fine and will compound one’s drainage issues and exacerbate one’s fungus gnat tissue.

Furthermore, Horticulture sand is also preferred because they do not alter the pH and is coarse. 

Remember that sand must be rinsed before use; thus, builder’s sand and pool filter sand are the topics of discussion.

To solve fungus-gnat problems, try covering your potted plants’ soil surface with a light layer of sand, which dries out quickly and discourages egg hatch.

Mulching potted plants with sand would provide a barrier to gnats and moisture-loving fungus.

Will Burning Leaves or Shrubs Damage Sand?

Although burning leaves and shrubs are very harmful to the environment, they can cause various damages to the atmosphere and soil. 

The heat of the fire burns away all the vegetation and organic matter on the soil’s surface, which makes some nutrients more readily available to the soil while turning others into lost gases (chiefly nitrogen).

Fire is often among disturbances that can cause destruction and destabilization and some amount of sand deflation.

In the case of sand, throwing enough sand on fire will block the Oxygen in the air from reaching the fuel, and heat and fire will go out. 

Though it is worth noting, sand that is reduced to dust won’t burn, but it is a health hazard, so one should not breathe in the sand as it is not good for us.

Sand pH increased by 39% after the fire, suggesting reduced soil acidity and increased liming. Total nitrogen increased by 100%; other nutrients (Ca2+, Mg2+, and K+) also increased.

The Takeaway:

The mystery of whether sand is flammable or not is solved as we discussed earlier that sand is made up of silicon dioxide. 

The absence of unoxidized silicon dioxide makes it flammable. Silica is non-flammable, non-combustible, and non-explosive.

Regular sand is chemically reactive, while silica sand is inert due to the different combinations of the elements in each of them.

Sand is an essential component to make a good soil mix; however, too much sand can make it difficult for soil to retain nutrients and water. 

Various plants grow in sand.

However, few types of sand help remove fungus gnats from plants, such as Horticulture sand and pool filter sand.

Although burning leaves are dangerous for the environment, when it comes to sand, it can cause deflation. 

Though sand cannot catch fire and are not combustible, it can still be harmful if burnt at a high temperature and exposed to it.

JayLea

JayLea has a passion for plants and has been gardening since 2015. He has valuable knowledge about gardening and houseplant care and can answer everyday practical questions that every plant owner has.

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