White Ash Weed and Why it Happens

Written By: Jay Hyung
Bong Engineer

Does white ash in your weed really mean a proper flush or better buds? U.S. wildfire research shows that the main determining factor for ash’s color is actually temperature.

Verdict: Nitrogen concentration is what makes the ash black in your weed.


As you light your weed the nitrogen content decreases, which turns the ash from black to gray to white.


Did you know that the same white ash vs black ash debate exists in the cigar world? White ash is believed to be a result of cigars being planted in nutrient-dense soils (more on this below).


In this guide we uncover why your weed ash may be white, black, gray, and if it even matters.

Does white ash
mean good weed?

What does white ash mean?

white ash weed

Yes in some cases, white ash does mean good weed and that can be found deep down in the soil.


When it comes to tobacco, white cigar ash indicates that it is grown in rich and nutrient-dense soil and black ash indicates fewer minerals in soils.


Mineral content is important because it impacts the flavor when inhaling weed. The fewer minerals the harsher the taste and smell.


When it comes to your weed ash, you may see white ashes for the following reasons:

Nutrients in soil
impacts weed ash color

White ash weed = nutrient rich soil

I first ever heard of white ash weed from an organic cannabis cultivator buddy of mine.


Organic cannabis is grown entirely naturally with soil, compost, fertilizer, and zero added chemicals.


All the cannabis he grew was in super nutrient rich soil and fertilizer, resulting in some of the cleanest smoking and tasting weed – that of course produces white ash weed.


So if your weed ash color is white it could be that the soil in which the cannabis was grown was loaded with nutrients.


Black ash, however, can be an indicator that the cannabis was grown in soil lacking proper nutrients.

Smoking temperature
create white ash cannabis

Temperature controls ash color

Research shows that ash color is directly related to combustion temperatures.


When cannabis burns at a higher temperature for longer periods of time, the ash becomes whiter naturally.


Why does this happen?


Carbon is what makes ash black and as you light cannabis (temperatures increase) the carbon reduces (resulting in the black ash turning white).


Pure white ash means that the bud has become “carbonless”.


White ash can be produced by simply increasing temperature and the duration of combustion.


With enough time and heat, ash can turn white regardless of whether it is a good bud or not.


So, yes, white ash could mean you have some really nutrient healthy cannabis plants.


At the same time it also could just mean your temperatures when smoking increased high enough to turn the ash white.


An easier way to tell if you have good buds is: it smokes smooth, taste good, and you get a great head and body high.

Can flushing change
weed ash color?

The big debate on white ash weed

Flushing cannabis is currently one of the main reasons people believe white ash means better buds.


Flushing marijuana plants is usually done a week or two before harvest, and by flushing all the plants with reverse osmosis water, it removes all the feed additives inside of the grow medium (like the soil for example).


Since no new nutrients are entering the process, the cannabis plant is forced to use up all its remaining minerals and nutrients in the grow medium and inside of the plant.


Flushing usually results in a better tasting weed experience and a much smoother smoke.


It’s also widely believed that flushing results in white ash, but this opinion is widely debated.


It’s a case by case situation and in some cases it could be true that your weed ash is white because of a super clean flush – or not!

White Ash vs Black Ash Weed

Come to find out it's all the same

white ash vs black ash

So what’s the difference between white ash vs black ash in cannabis?


When marijuana plant material burns, the heat from the surface burning will char the layer underneath.


This charring of the second layer of marijuana produces carbon which is black.


With the ideal conditions 
(adequate oxidation and heat), the carbon will burn off leaving only the mineral components of the cannabis plant.


Which results in white ash.


When white ash forms it actually forms on the top layer of the black ash.


So essentially when you see white ash, you are seeing black ash with just a layer of white.

Why is my
weed ash black?

Overfertilization causes black ash

Growers use chemical products to boost their yields (more weed, more money).


All these added chemicals result in very heavily fertilized or even chemically sprayed plants.


Headaches and panic attacks are some of the reported side effects of very over fertilized or sprayed buds.


Overfertilization or under fertilization of cannabis plants can lead to black ash.

Poorly cured weed
creates black ash

Moisture in weed causes black ash

When weed dries and cures correctly, the remaining sugars continue being metabolized.


These compounds break down slowly and are released gradually into the atmosphere.


If you cure and dry your buds too quickly, what happens is some of the heavier compounds may remain in the bud (such as chlorophyll and other sugars) as they didn’t have enough time to break down.


Essentially these compounds remain in the bud delivering a harsher hit and at time a bud with inconsistent moisture levels.


The moisture content due to improper curing (drying), can lead to white ash as well.


Ash size matters
more than ash color

Focus more on ash length (cooling)

Ash color, whether white or black, isn’t truly an absolute indicator of cannabis quality.


The length of the ash is actually more important than color.


The length of the ash impacts the flavor of the blunt or joint.


For example having one inch of ash at the foot of your blunt or joint helps to control airflow.


This keeps your blunt or joint cooler which helps to smooth and soften the weed smoking experience.

Joint ash Tips

Focus more on ash length (cooling)

The joint ash usually is black with a white ash layer on top.


The color of ash on your joint isn’t an indicator of cannabis quality, but rather how well the joint is oxidizing and combusting.


Do not tap the ash on your joint!


Let the joint ash run as long as possible. 


You want to see a good quarter inch of ash running at the end of your joint.


The white ash is a sign your joint is combusting well (higher heat levels create the white ash).


You want as much ash build up at the end of your joint to help cool the smoke.


Ash works as a cooling mechanism so you never want to prematurely remove any ash from the joint.


Ever notice when you tap the ash off your joint the pulls are instantly hotter in your lungs?


The ash is actually meant to help cool the smoke, so the longer the white ash build up the easier and better quality smoke.

White Ash Blunt

Focus more on ash length (cooling)

Blunts are a bit different from joints as the paper is much thicker and can be different forms of leaves much similiar to cigars.

Cigar leaves help to have some of the longest running ash trails.

The longer the ash at the end of your blunt, the smoother and more productive the hits will be.


Make sure you let as much of the blunt’s ash into

Final Thoughts on White Ash Weed

The debate about white ash weed has been going on for quite some time.


While it’s true flushing, nutrients, and additives (plant growth chemicals) can and may affect weed ash color, it can all be trumped by temperature.


What does white ash mean? Well you could have good weed where burning temperatures were too low and that good weed created black ash.


So does white ash mean good weed? Not always but it can. Saying that white ash from weed is the be-all and end-all in debates of cannabis quality is not true.


When it comes to this white ash vs black ash it really doesn’t matter. Your weed is good if it smokes good, taste good, and hits good. White ash weed is primarily an indicator of temperature and that’s it.

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