The short answer
Rooting hormone is not magic, but its effect is measurable. In a controlled study on cannabis stem cuttings, IBA (indole-3-butyric acid) increased both rooting success rate and root quality compared with untreated cuttings. Those are the two things that decide whether propagation week goes well: how many cuts root at all, and what kind of root system they push. If you take your own cuts, that is what a good hormone dip buys you. If you buy already-rooted clones, someone else has already done this step for you.
What a cutting is actually doing
Start with what a clone is. A plant grown from a stem cutting is a genetically identical copy of the parent, which is the entire reason clone menus exist: you are buying a known phenotype rather than rolling the dice on a seed. The cutting itself has no roots yet, so its first job is to grow some.
That happens through adventitious root formation. Roots initiate at the wounded basal end of the stem, right where you sliced it. The wound is not damage to avoid; it is the trigger site. Everything you do during propagation — how you cut, what you dip it in, how humid you keep the air — is really just protecting the cutting while those new roots organize and emerge.
What IBA does
IBA is a synthetic auxin, a plant hormone involved in root initiation, and it is the treatment that produced the gains described above. In the cannabis study, auxin-treated cuttings outperformed untreated cuttings on both rooting percentage and root quality scores. More roots, better roots.
Concentration matters. Liquid IBA dips for cuttings typically run in the range of 500 to 1,000 parts per million, and the right rate is species-specific, so follow the product label rather than forum folklore.
Technique matters more than the bottle
Hormone amplifies your technique; it does not replace it. Three habits move the needle more than any product choice:
Take cuts from healthy, disease-free mother plants. Stock plant condition directly affects rooting percentage, and a weak mother produces weak cuttings no matter what you dip them in.
Keep some leaves on. In the cannabis trial, cuttings retaining three leaves scored higher on root quality than cuttings trimmed down to two, even though rooting rate was similar. Leaves feed root initiation, so leave a little photosynthetic engine attached.
Strip any flowers or buds from propagation material. Flowering tissue competes for the plant's energy, and removing it redirects resources toward root production. A flowering cutting is fighting itself.
Humidity closes the deal
An unrooted cutting cannot replace the water it loses, so ambient humidity is the difference between a turgid cutting and a crispy one. A humidity dome or regular misting slows water loss dramatically while the root system forms, which buys the cutting time to establish. Crack the dome for airflow periodically though, because still, warm, humid air is exactly what powdery mildew enjoys.
When you do not need it at all
If your clones arrive already rooted, the hormone question is settled before the box is opened. That is the model we work from at Clone Source: clones propagated from verified mother stock and PCR-screened for HLVd, Fusarium, and Pythium, shipped Monday through Wednesday so they never sit in transit over a weekend. Every order carries a 48-hour arrival claim window, so if a plant shows up in bad shape, you document it and contact orders@clone-source.com or (720) 375-5261 within two days.
Where rooting hormone still earns its shelf space is in your own mother-and-cutting workflow. Take your cuts from tested stock, keep three leaves on, strip the flowers, dip to label rate, dome them, and let the biology do the rest.
