What Causes Wood Stain To Be Blotchy & How To Prevent It?

paint stain wood brush

Blotchy wood stain can make a well-done project look atrocious. Don’t let all that hard work go to waste by not properly staining your project, make sure to take careful steps to ensure an even, sleek look.

Blotchy wood stain is caused by wood soaking up stain unevenly due to wood density or by leaving excess stain on the wood for too long.

How To Prevent It

The first step in preventing blotchy wood stain is to make sure that your project is well sanded with high grit sandpaper. Start out with lower grit and work your way up in order to get a nice smooth surface.

Rough surfaces will cause the stain to pool in certain places making those areas darker than the rest giving you the blotchy effect. Applying a wood conditioner after sanding will help the stain absorb more evenly. When applying the stain it is important to not get too much on the brush at once and apply the stain evenly across the wood. This will also prevent any dripping which would also make the stain blotchy.

Any area with extra stain should be brushed again to get it even. Make sure to wipe of the stain per the manufacturer’s recommendation, usually after about three minutes, and never leave stain on the wood to dry without removing the excess.

Hot To Fix Wood Stain Blotches

To fix the area you will need to sand it down. Depending on how long the stain was left on the wood, and subsequently how deep the stain is, it may take several passes in order to lighten the dark patches. You should use a medium grit sandpaper, nothing too rough so that you don’t harm the project before moving to fine grit.

Also, sand around the area of the dark spot so that it can be blended properly. When you stain the area again make sure to not overlap what you have already done so it doesn’t get darker than you want it. You will need to carefully blend the new are with the already stained part.

How To Stain Wood Evenly

The wood that you are staining should be well sanded, rough surfaces will cause the stain to pool. Apply the wood conditioner as you would the stain, in even strokes along the path of the wood grain.

When applying stain to the wood, make sure you don’t pick up too much stain on the brush at one time, always wipe the bristles on the inside lip of the can to remove excess stain. Apply the stain in even strokes in the direction of the wood grain. Brush out any area where stain may have puddled. Once the wood has gotten to the desired color tone wipe off all of the excess stain per the manufacturer’s recommendation.

The entire area should be stained all at once to ensure evenness. Its always a good idea to test the stain you will be using on a scrap board that is the same wood as your project to make sure you know what it will look like when you are done.

Will Polyurethane Even Out Stain?

Generally Polyurethane is used as an after coat to seal the stained wood, but you can use it to help even out the stain by applying a coat over the blotchy area and then a gel stain over the top of the Polyurethane. After applying the Polyurethan you will want to lightly sand the blotchy area and then apply the gel stain over the top.

This will mask the area without allowing the stain to penetrate the wood any further. This can be a tricky process as you need to make sure that you keep the same consistent hue as the rest of the area around the blotchy spot.

You can also use a coarse bristle brush to scrape the spot beforehand and try to get it blended before applying the Polyurethane technique. This may not be necessary if the blotchy area is not very large or the difference in hues is not very big.

Are Some Stains Better At Reducing Blotchiness?

In general, using a gel stain helps to reduce blotchiness because the stain is held suspended in the gel base and cannot be overly absorbed by the wood. The staining process is the same as a normal liquid stain, but you want to make sure and thoroughly stir the gel in order get any liquid at the top of the can mixed in evenly to avoid overabsorption.

The down side to a gel stain is also in its effectiveness, since the gel is meant to keep from penetrating the wood as much as a normal stain you will not get the deep hue that you otherwise would using the normal stain. This may not be an issue for you but it’s a good thing to keep in mind.

As you would expect, Miniwax is one of the most popular makes of gel stains. However, I’d also suggest giving General Finishes a try. They aren’t as common in the big box stores, but I’ve had great success using their product, which you can find here (Amazon link).

Does Wood Type Affect Staining?

Yes, the type of wood you are using will affect the absorption rate of the stain. Hardwoods such as walnut, oak and maple won’t absorb the stain as fast due to the density of the wood whereas wood varnish stain brush pinesofter woods like pine and douglas fir will absorb the stain much quicker.

You will also notice that the humidity of the wood will affect how well the stain is absorbed as well. The drier the wood, the more room in the pores there is to absorb the stain, while wood with a higher water content will take on less of the stain. Keep these factors in mind when you begin your project and think about the staining process and how the wood will react before you get started, this will help alleviate any heartache later from poor wood or stain combination choices.

How Brushes Affect The Staining Process

Believe it or not the type of brush you use can affect how your stain is applied and subsequently whether or not you will get stain blotches. When using an oil-based finish, you want to have a natural bristle brush because the fine bristles hold more stain. Waterborne finishes are best applied using a synthetic brush since the bristles won’t lose their stiffness.

You can also purchase hybrid brushes that combine both synthetic and natural bristles. When staining also remember to only dip about the first quarter of an inch of the bristles into the stain to avoid getting too much at once and having the stain pool.

Using Wood Filler And Stain Together

If you have used wood filler on your project at all it will be difficult to avoid blotchy or darker looking spots, even if it is stainable wood filler. Just as with the differences in wood type can affect how the stain is picked up it is the same with the wood filler.

The wood filler will soak up the stain at a different rate than your wood, creating either a lighter or darker blotch spot. Its best not to use wood filler on any visible area that you plan on staining to avoid this.


The key elements to remember when staining to avoid blotchiness are first to make sure that the wood is properly sanded. This is one of the most fundamental elements in ensuring that the wood takes on the stain in an even manner. The smoother the wood the more uniform your stain absorption will be.

Secondly, remember that using a wood conditioner before applying the stain will also assist the stain in being applied evenly. And third make sure that when applying the stain you are using the correct type of brush and you only dip it in the stain about a quarter of an inch so as to not get too much on and create pooling.

Staining evenly can be a challenging process, even for advanced wood workers, but remember to take your time and follow these tips and your project will turn out better for it.