How to Use Baking Soda in Laundry

Baking soda (sodium bicarbonate) is one of those genuinely useful laundry additions that most people either don't know about or use wrong. It's not a detergent replacement — but it amplifies your detergent, neutralizes odors, and helps with specific stain and brightness problems.

Here's where baking soda actually delivers results and how to use it correctly in your laundry routine.

Why Baking Soda Works in Laundry

Sodium bicarbonate is a mild alkali (pH around 8.3). In the laundry context, this chemistry does a few useful things:

• Stabilizes water pH — both very hard water (alkaline) and very soft water (slightly acidic) can reduce detergent effectiveness. Baking soda buffers the wash water toward a more neutral-alkaline pH where detergent surfactants work most effectively
• Boosts detergent performance — by optimizing pH, it makes your existing detergent work harder. You may be able to use slightly less detergent with the same cleaning result
• Neutralizes odors — baking soda neutralizes both acidic odors (like sweat) and some alkaline odors by bringing both toward neutral. It doesn't mask odors — it chemically converts them
• Mild abrasive action — as a paste, baking soda provides gentle mechanical scrubbing action on stains without damaging most fabric fibers
• Brightens whites — helps remove the yellowing caused by body oil and mineral buildup in white fabric fibers

How to Use Baking Soda in a Regular Wash

The simplest and most effective use of baking soda in laundry is as a detergent booster:

1. Add your regular detergent to the detergent dispenser as usual
2. Add ½ cup of baking soda directly to the drum — not the dispenser
3. Wash as normal

This works for all fabric types and all wash temperatures. The baking soda dissolves in the wash water and helps the detergent clean more effectively. Particularly beneficial in hard water areas where mineral content reduces detergent efficiency.

Removing Odors from Laundry with Baking Soda

Pre-soak for heavily odorous items

For gym clothes, sports gear, or anything with persistent sweat smell that regular washing doesn't fully remove:

1. Fill a basin or the machine with cold water
2. Add ½ cup baking soda and stir to dissolve
3. Submerge the items and soak for 30–60 minutes (up to overnight for severe odor)
4. Wash as normal with detergent

This pre-soak is especially effective for synthetic fabrics (polyester, nylon, spandex) that trap sweat odor in the fiber structure in a way that direct washing often doesn't reach.

Adding to the wash for general freshness

For everyday odor maintenance — especially for towels, bedding, and workout clothes — add ½ cup baking soda to each wash. This keeps items smelling fresher between washes and reduces the "used towel smell" that develops over time.

Whitening and Brightening with Baking Soda

Baking soda is a gentle whitening agent that works on yellowed whites caused by body oils, mineral deposits, and detergent buildup:

Regular maintenance of white clothes

Add ½ cup of baking soda along with your regular detergent on every white-clothes wash. Over multiple washes, this prevents the gradual yellowing that happens to white cotton.

Brightening treatment for yellowed whites

1. Fill the machine with the hottest water safe for your fabric
2. Add 1 cup of baking soda — no detergent yet
3. Let items soak for 30–60 minutes with the machine paused or in a pre-soak cycle
4. Add detergent and complete the wash cycle normally

For severe yellowing, combine with oxygen bleach (OxiClean) — baking soda and oxygen bleach work synergistically and are safe to combine (unlike baking soda and chlorine bleach, which is safe to combine but you lose the bleach's effectiveness).

Pre-Treating Stains with Baking Soda Paste

Baking soda paste works well as a gentle pre-treatment for:

• Sweat stains on collars and underarms
• Light grease stains
• Food stains on sturdy fabrics
• Collar rings on shirts

How to make and use the paste

1. Mix baking soda with just enough water to form a thick paste (about 3 parts baking soda to 1 part water)
2. Apply the paste directly to the stain
3. Work in gently with a soft toothbrush or fingertip
4. Leave for 30 minutes (or up to a few hours for tough stains)
5. Brush off the dried paste
6. Wash as normal

For sweat stains specifically: add a few drops of dish soap or hydrogen peroxide to the baking soda paste for a more powerful pre-treatment.

Deodorizing the Washing Machine with Baking Soda

If your washing machine has developed a musty or sour smell, baking soda can help clean it:

1. Add 1 cup of baking soda directly to the drum — no clothes, no detergent
2. Run a hot empty cycle
3. For persistent odors, follow with a second cycle using 2 cups of white vinegar (run separately — don't combine baking soda and vinegar in the same cycle)

What Not to Mix with Baking Soda

Don't mix with vinegar in the same wash

Baking soda is alkaline; vinegar is acidic. When combined in laundry, they neutralize each other (you'll see fizzing, which is the reaction releasing CO₂). This isn't dangerous, but it's counterproductive — you lose the benefits of both. Use them in separate washes or in different parts of the wash cycle.

Be careful with chlorine bleach

Baking soda and chlorine bleach can be used in the same wash without producing toxic compounds, but the baking soda reduces the effectiveness of the bleach. If you're using bleach to whiten or sanitize, leave out the baking soda that wash.

Frequently Asked Questions

Can baking soda replace detergent?

No. Baking soda doesn't contain surfactants — the molecules that actually lift oil and dirt from fabric. Without surfactants, you're cleaning with alkaline water, which helps a little but doesn't clean adequately. Always use baking soda alongside real detergent, not instead of it.

How much baking soda should I use per load?

Half a cup (about 120g) per standard load. A full cup for large loads or heavily soiled items. For pre-soaking, use ½ cup per gallon of water.

Is baking soda safe for all fabrics?

Baking soda is generally safe for most fabrics at normal concentrations. It's mild enough for cotton, polyester, and linens. Use sparingly on very delicate fabrics (silk, cashmere, wool) and avoid leaving concentrated baking soda paste on delicate fibers for extended periods.

Does baking soda damage washing machines?

Regular use in normal amounts (½ cup per wash) won't damage machines. Avoid leaving large quantities undissolved against rubber seals for extended periods.

The Bottom Line

Baking soda works best as a detergent booster, odor neutralizer, and sweat stain pre-treatment. Add ½ cup to the drum with your regular detergent and you'll notice cleaner, fresher results — especially on gym clothes and towels. Don't expect it to replace detergent, but as an addition to your laundry routine, it earns its place.

For more natural laundry solutions, see our guide on how to use white vinegar in laundry.