Is Candle Wax Bad For Soil?

Candle wax is made up of a variety of hydrocarbon compounds. The most common types used in candles are paraffin wax, stearin wax, beeswax, and soy wax Elements of a Candle: Wax. The chemical formula of paraffin wax, one of the most common types, is C31H64. In general, candle wax consists of long chains of carbon and hydrogen atoms What is Candle Wax made of Chemically?. When candle wax makes its way into soil, it can have both benefits and downsides. It may help retain moisture and add organic matter to the soil. However, it could also alter soil pH and microbial life. This article will explore the potential impacts of candle wax in soil in depth.

Candle Wax Composition

chemical structure diagram of paraffin wax

The main ingredients in candle wax include paraffin wax, soy wax, and beeswax. Paraffin wax is a petroleum-based wax made from refining crude oil. Its chemical makeup consists of straight chain alkanes including n-alkanes, isoalkanes, and cycloalkanes with 20 to 40 carbon atoms (Source:

Soy wax is made from hydrogenated soybean oil. Its chemical makeup contains fatty acids, including palmitic, stearic, oleic, linoleic, and linolenic acids (Source:

Beeswax is a natural wax produced by honey bees. Its chemical makeup contains over 300 compounds, including palmitate, palmitoleate, hydroxypalmitate, oleate, linoleate, linolenate, stearate, and palmitolic acid esters (Source:

Benefits of Candle Wax in Soil

Candle wax can provide some benefits when added to soil, mainly due to its potential to improve nutrient content and water retention properties. Most modern candle wax is made from paraffin, a petroleum byproduct, or natural waxes like soy, beeswax, or palm wax.

Soy wax in particular has been found to enrich soil with nutrients like nitrogen, phosphorus, and potassium that plants need to thrive. According to research from the University of Illinois, soy wax contains soybean oil with nutrients that can improve soil fertility ( The organic matter in soy wax can also help soil retain more moisture.

Beeswax and paraffin wax likewise introduce organic materials into the soil as they biodegrade. This can improve water retention, aeration, and microbial activity. However, paraffin is not a renewable resource, while soy and beeswax are considered more sustainable options.

Overall, adding small amounts of candle wax to soil as part of compost or directly can supplement key nutrients and potentially help plants grow, especially when using natural waxes. But more research is still needed on optimal amounts and long-term impacts.

Potential Downsides

While there are benefits to using candle wax in soil, some gardeners have concerns about potential downsides. One concern is around toxicity. According to (, paraffin wax candles release chemicals into the air when burned that can contribute to water pollution. There are concerns that any leftover paraffin residue in candle wax added to soil could potentially leach chemicals into the groundwater. More research is needed on toxicity and biodegradability of specific candle wax components.

Another potential downside is the impact on soil pH. Most plants prefer a soil pH between 6.0-7.0. According to some gardeners, adding candle wax may make the soil more alkaline. However, more controlled studies are needed to conclusively determine effects on pH. The impact likely depends on the soil composition, amount of wax added, and the specific plants grown. Monitoring soil pH regularly when adding candle wax is recommended.


When disposing of candle wax, it’s best to avoid dumping it directly into soil or compost. Here are some better alternatives:

person weighing and mixing compost materials

  • Recycle the wax if possible. Some recycling centers accept candle wax, and it can be repurposed into new candles or wax melts (
  • Repurpose candle jars, melt down the wax, and make new candles (
  • Throw away candles and hardened wax in the regular trash. The wax will not biodegrade but modern landfills are designed to contain non-biodegradable materials.
  • Compost wax from unscented, organic soy or beeswax candles. Paraffin wax should not be composted.

Avoid pouring hot liquid wax directly into soil or compost, as this can damage microbial life. Let wax fully harden first before disposal. With some creativity, most candle wax can be recycled or repurposed rather than dumped irresponsibly.

Impact on Specific Plants

Candle wax can have varying effects on different types of plants, especially common vegetables grown in home gardens. According to, paraffin wax is generally considered non-toxic and safe for plants. However, some studies have raised concerns about potential toxicity to vegetable plants from chemicals released as the wax burns. One study found that carrots grown in soil contaminated with paraffin wax residues had reduced germination rates and growth compared to a control group.

carrot plants growing in soil

For other common garden plants like tomatoes, cucumbers, lettuce and peppers, research is limited on the specific impacts of candle wax. Since paraffin is petroleum-based, there are concerns that hydrocarbon compounds could be absorbed by plants, leading to reduced yields or abnormal growth. However, more research is needed to fully understand these potential risks. Gardeners concerned about potential toxicity may want to avoid dumping used candle wax directly into vegetable garden beds as a precaution until more definitive evidence is available.


The breakdown time of candle wax in soil depends on the type of wax. Paraffin wax, a common candle wax, is slow to decompose according to this source. In landfills, paraffin wax can take years to break down. However, natural waxes like soy wax or beeswax are more readily biodegradable, breaking down within months in ideal composting conditions.

As candle wax decomposes, it releases byproducts including alkanes, alkenes, and toxic chemicals like toluene and benzene. The release of these chemicals, especially from petroleum-based waxes like paraffin, can have negative impacts on soil health and the surrounding environment. Slow breakdown times mean sustained exposure to the chemicals released during decomposition.

Relevant Studies

There have been a few studies that have examined the effects of candle wax on soil composition and plant growth. One of the earliest studies was by LJ Briggs in 1911, published in the Journal of the American Society of Agronomy. This study looked at moisture retention in soils with candle wax residues and found that soils still contained moisture even when plant covers had wilted (Briggs, 1911).

More recently, some studies have compared paraffin wax from candles versus soy wax alternatives. One analysis by Happypiranha (2022) found both paraffin and soy waxes to be biodegradable and safe for use in candles. They cited no evidence that either wax was dangerous to health or the environment (Happypiranha, 2022).

Overall, the scientific research suggests candle wax residues have minimal negative effects on soil properties or plant growth. Key findings indicate candle wax can help retain soil moisture. Both paraffin and soy wax candles appear to be biodegradable options.

Environmental Effects

Many types of candles, especially traditional petroleum wax-based candles like paraffin, are not eco-friendly and can have negative impacts on the environment. Burning paraffin candles produces the same harmful byproducts, particulates, and carbon as burning fossil fuels.[1] Paraffin wax itself is derived from petroleum oil, requiring resources to extract and refine. The harvesting of paraffin wax can lead to contamination of land and water sources from oil spills or other leaks and can contribute to climate change effects of using fossil fuels.[2]

burning candle emitting smoke

When burned, paraffin candles release chemicals like toluene and benzene into the air. These can contribute to air pollution and respiratory issues when inhaled. The soot released can also contribute to water pollution when rained out of the air into lakes and rivers. [3] In terms of soil health, paraffin wax takes thousands of years to biodegrade so any wax that ends up in the soil can persist for long periods.


In summary, while small amounts of candle wax are likely fine in soil, larger amounts or frequent dumping could have downsides. Candle wax can provide some benefits to plants and soil organisms by adding organic matter. However, it can also alter soil pH, hydrophobicity, and drainage in higher concentrations. The biggest risks are to young seedlings and acid-loving plants that don’t tolerate changes in soil pH well. For most plants, a one-time application of candle wax will likely not cause issues, but dumping regularly or in quantities over 10-20% of soil volume could start to negatively impact plant health and soil ecology. The safest recommendation is to avoid making candle wax a primary soil amendment and limit applications to small, occasional amounts.

Overall, the occasional and sparing use of candle wax on soil as a byproduct of candle-burning is likely fine. But gardeners should be cautious about excessive dumping of large melted candle wax quantities directly in soil, and monitor plant health if doing so repeatedly. The safest course of action for candle enthusiasts who want to protect their plants is likely to use receptacles under the candles, and dispose of solidified wax thoughtfully.

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