How to prep new cloth diapers
New cloth diapers need to be washed before first use. Natural fibers — bamboo, hemp, cotton — come from the factory with residual oils that repel liquid until they're washed out. Synthetic microfiber and PUL shells need a single pre-use wash mostly for sanitation. Skip this step and you'll get leaks from day one, which is why "prepping" is one of the most common questions new cloth diaper users have.
The short version: EcoAble cloth diapers are safe to use after one wash with detergent. But natural-fiber absorbents (bamboo, hemp, cotton) don't reach full absorbency until 3–5 wash-and-dry cycles have removed the natural oils. You can use diapers during this window — just expect some leaks and change more frequently until they're fully prepped. Never boil EcoAble diapers, and keep wash temperatures under 130°F (54°C) to protect the PUL, elastics, and snaps.
Why prepping matters
Natural fibers — the bamboo, hemp, and cotton that make up the absorbent core of most cloth diapers — contain natural plant oils from the growing and manufacturing process. These oils are water-repelling, so when you pour liquid onto an unprepped insert, it rolls off or beads up instead of soaking in.
Each wash-and-dry cycle removes more of the oils. By the 3rd–5th cycle, the fibers are fully "open" and have their full absorbent capacity. Some materials (especially hemp) continue to improve in absorbency slightly beyond that, but for practical purposes they're ready after a handful of washes.
Prepping isn't optional for new natural-fiber diapers — using them at day one means guaranteed leaks, and that's often misdiagnosed as a size, fit, or detergent issue when it's really just uncured fabric. One wash is enough to make them sanitary and usable; more washes make them work properly.
How many washes by fabric type
Different fabrics need different amounts of prepping. Most modern diapers combine fabrics, so work off the longest prep requirement in the diaper — a bamboo-cotton blend needs as many washes as the slower fabric of the two.
| Fabric | Minimum washes before use | Washes to full absorbency | Notes |
|---|---|---|---|
| Bamboo | 1 | 3–5 | Reaches near-full capacity quickly; most common fabric in EcoAble diapers. |
| Hemp | 1 | 5–8 | Highest long-term capacity, but slowest to reach full absorbency. |
| Cotton | 1 | 3–5 | Quick to prep; fewer oils than bamboo or hemp. |
| Microfiber | 1 | 1 | Synthetic — no natural oils. Ready after one sanitary wash. |
| PUL shells & covers | 1 | 1 | Not absorbent — just needs one wash for sanitation before use. |
| Stay-dry fleece / athletic wicking jersey | 1 | 1 | Wicks moisture away from skin — doesn't absorb. Ready after one wash. |
A bamboo-hemp insert needs the hemp prep count (5–8 washes). A bamboo-cotton insert is ready in 3–5. If the care label doesn't specify, assume the longer count — overprepping doesn't hurt anything.
The prep process
Prepping is just repeated wash-and-dry cycles with regular detergent. No special treatment, no stripping, no soaking. The goal is to rinse out the natural oils, which takes time and normal wash agitation.
If you have removable inserts, prepping them separately from PUL shells lets you run hotter water on the absorbents without stressing the laminate. Not mandatory — you can prep a whole diaper together — but faster if you have a large stash to prep at once.
What to avoid when prepping
Prepping is gentle — the goal is removing oils, not sanitizing or deep cleaning. Aggressive methods damage diapers without speeding up the prep process.
- Don't boil them. Boiling is sometimes suggested online as a fast prep for hemp, but it delaminates PUL shells, melts plastic snaps, damages elastics, and can shrink natural fibers unevenly. Even for insert-only pieces without PUL, boiling is unnecessary — washing works.
- Don't use water above 130°F (54°C). Very hot water can cause delamination, PUL cracks, snap melting, excessive shrinkage, and other damage. Keep the washing machine at warm or below for prepping.
- Don't line dry in direct sun on a very hot day. UV is fine for stain removal later, but on very hot days direct sun on PUL shells can crack the laminate. Shade or indoors is safer during prep.
- Don't strip new diapers. Stripping is for removing buildup, not natural oils. It wears out elastics for no benefit on a fresh diaper.
- Don't use fabric softener, ever. Not during prep, not after. It permanently coats fibers and prevents absorption — the exact opposite of what you're trying to do.
- Don't use bleach during prep. Not needed on new diapers, and unnecessary bleach exposure shortens PUL and elastic life.
Using diapers during prepping
You don't have to wait until prepping is complete to start using new diapers. After the first wash they're sanitary and safe — they just won't hold as much liquid as they eventually will.
A reasonable way to start:
- Wash 1: Diapers are safe for use. Expect about 50–60% of full capacity. Change more frequently than your target schedule.
- Washes 2–3: Capacity is climbing. Still change more frequently than normal — plan for some leaks.
- Washes 4–5: Bamboo and cotton diapers are at or near full capacity. You can run a normal change schedule.
- Washes 6–8: Hemp inserts reach their final capacity. Anything still leaking after this point is not a prep issue — see the why cloth diapers leak guide.
If you're starting with a brand-new stash and no backups, plan to change diapers every 1.5–2 hours for the first week instead of the usual 2–3. This covers the lower capacity during prep and also builds a natural prep rhythm — every change means a dirty diaper to wash, which is another prep cycle.
How to know diapers are fully prepped
There's no exact indicator — it's a feel check. A few signs that prepping is complete:
- Water soaks in instantly when you pour it on the insert. Unprepped inserts bead water on the surface for a few seconds; fully prepped inserts absorb immediately.
- Leaks stop happening at normal change intervals. If a diaper holds 3 hours of normal output without leaking, it's ready for your regular schedule.
- The fabric feels softer and more pliable. Unprepped natural fibers are slightly stiff; washed fibers soften and relax.
If you're past 8 wash cycles and the diapers still feel or perform like they're unprepped, something else is happening — most likely detergent buildup or hard water. See the leak troubleshooting guide.
Common questions
Can I use EcoAble diapers after just one wash?
Do I need to wash diapers before use if the tag says "pre-washed"?
Should I prep covers and PUL shells the same way as inserts?
Can I speed up prepping by using hot water?
Do I have to dry between each wash cycle?
Is prepping the same for adult cloth diapers as baby diapers?
My diapers are still leaking after 5 washes. Are they defective?
Can I prep diapers along with my regular laundry?
Should I test absorbency after prepping?
Once your diapers are prepped
The prepping guidelines on this page are for EcoAble cloth diapers. Check the care label on any specific diaper for manufacturer-specific instructions. EcoAble disclaims all liability for damage resulting from prepping methods used. Never boil diapers, use water above 130°F (54°C), or expose PUL to direct high heat.