Do I need rooting hormone for clones?

Q: Do I need rooting hormone for clones?

You don't strictly need rooting hormone for cannabis clones, but it clearly helps. In a controlled study, an IBA gel gave 2.1 times the rooting success of a willow-extract gel, and in hemp, hormone-treated cuttings rooted far better than untreated ones. Use an IBA gel or powder (commonly 1,000–3,000 ppm), dip once from a decanted portion, and expect roots in 7–14 days.

Short answer

Not strictly, but use it. An IBA rooting gel gave 2.1 times the rooting success of a willow-extract gel in cannabis, and hormone-treated hemp cuttings rooted far better than untreated ones. Expect roots in 7–14 days with hormone. Supported.

Why

Rooting hormones are synthetic auxins, mostly indole-3-butyric acid (IBA). Auxin at a fresh wound triggers adventitious roots, so cuttings root sooner and more evenly.

The cannabis evidence is direct. IBA gel beat a willow-extract gel 2.1 times on rooting success and 1.6 times on root quality ^[1].

The hemp evidence agrees. Across eight cultivars, hormone treatments raised rooting success well above untreated controls, but strength and form (1,000 or 3,000 ppm IBA powder, an IBA/NAA dip) made no significant difference ^[2].

Cannabis is not a hard-to-root plant, so some cuttings root without help. Hormone mainly buys reliability: more of the tray rooted, sooner.

The numbers

Option	Evidence	Result
IBA gel	Cannabis trial ^[1]	2.1× rooting success vs willow gel
IBA powder 1,000–3,000 ppm	Hemp trial ^[2]	Similar to other hormones; better than none
IBA/NAA liquid dip	Hemp trial ^[2]	Similar to other hormones
Willow extract	Cannabis trial ^[1]	Weaker rooting and root quality
No hormone	Hemp trial ^[2]	Lowest rooting

What to do

Buy an IBA gel or powder labelled for softwood cuttings.
Pour a small amount into a clean cap; discard leftovers.
Dip the fresh cut 1–2 cm deep, tap off excess, and stick it straight into the plug.
Keep the rest of the setup right: 22–26 °C medium, high humidity, gentle light.

Common mistakes

Dipping straight into the stock pot and spreading pathogens.
Soaking stems in strong liquid for minutes "to be sure".
Expecting hormone to rescue a cold, soggy plug.
Using old, stale hormone.

Full article: Clone-only cuts and how to preserve them
How do I clone a cannabis plant? · Can I root clones in water?
Terms: rooting hormone · auxin

Follow-up questions

Is gel or powder better for clones?

Neither is clearly better for cannabis clones. A hemp study compared IBA powders at 1,000 and 3,000 ppm and a liquid IBA/NAA dip and found no significant differences between hormone types or concentrations, while all beat no hormone. Gels stay on the stem and seal the cut, which many growers like. Whatever you use, pour a small portion out and never dip back into the stock.

Does willow water or honey work as rooting hormone?

Not as well. In a controlled cannabis study, a willow-extract gel gave less than half the rooting success of an IBA gel, at 2.1 times lower, and had poorer root quality. Honey has no good evidence in cannabis. If you want reliable, even rooting across a tray of clones, use a product containing indole-3-butyric acid (IBA).

Can too much rooting hormone hurt clones?

Yes. Very strong auxin doses or long soaks can burn the stem base, cause swollen callus with few roots, or yellow the cutting. Stick to the label rate, typically a quick dip for liquids and a light coat for gels or powders at 1,000–3,000 ppm IBA, and tap off the excess. More hormone is not more roots.

Sources

Caplan D, Stemeroff J, Dixon M, Zheng Y. 2018. Vegetative propagation of cannabis by stem cuttings: effects of leaf number, cutting position, rooting hormone, and leaf tip removal. Canadian Journal of Plant Science 98(5):1126-1132. doi.org/10.1139/cjps-2018-0038

Campbell SM, Anderson SL, Brym ZT, Pearson BJ, 2021. Evaluation of substrate composition and exogenous hormone application on vegetative propagule rooting success of essential oil hemp (Cannabis sativa L.). PLOS ONE 16(7): e0249160. doi.org/10.1371/journal.pone.0249160