When are rooted clones ready to transplant?

Q: When are rooted clones ready to transplant?

Rooted cannabis clones are ready to transplant when several white roots, about 2–5 cm (1–2 in) long, are poking out of the sides or base of the plug, usually 10–14 days after cutting. Harden them off from the dome over 3–5 days first. Move them into a 0.5–3 L pot of pre-moistened medium at the same pH and keep light gentle for a few days.

Short answer

Transplant rooted cannabis clones when several white roots, 2–5 cm (1–2 in) long, show at the sides or base of the plug, usually 10–14 days after cutting. Harden them off over 3–5 days, then pot into 0.5–3 L of pre-moistened medium. Grower practice.

Why

Roots have to supply the leaves once the dome comes off. One stub of root can't; a handful can.

Timing in trials matches. Hemp cuttings were judged ready 12 days after sticking, once more than half showed visible roots ^[2].

Moving too late costs too. Roots that circle a plug for weeks become a tangle that is slow to grow out into new medium.

Pot size should match the root ball. A small container wets and dries in step with a small root system, while a huge pot stays wet where there are no roots ^[1].

Rooted clones are also your backup. Holding a few as a slow line, alongside tissue culture banking, protects a genotype against loss ^[3].

The numbers

Sign	Ready?
No roots visible after 7 days	No, wait
One short root	Not yet
Several white roots 2–5 cm out of plug	Yes
Roots brown, matted, circling	Overdue

Step	Target
Hardening off	3–5 days, vents then lid off
First pot	0.5–3 L, ~2–4× plug volume
Medium pH	Soil 6.2–6.8; coco 5.8–6.2
Light after move	150–300 µmol/m²/s, rising

What to do

Check plug sides and bottoms from day 7; don't pull.
Open dome vents once roots show, then prop and remove the lid over 3–5 days.
Pre-moisten the new medium to "wrung sponge" and pH it.
Set the plug in whole, firm gently, water in lightly.
Keep light gentle for 2–3 days, then raise it.

Common mistakes

Transplanting the day the first root tip appears.
Moving clones and removing the dome on the same day.
Plug straight into a 20 L pot.
Tearing roots by pulling the plug apart.

Full article: Clone-only cuts and how to preserve them
Transplanting
How long do clones take to root? · Why are my clones wilting?
Terms: transplanting · hardening off

Follow-up questions

How can I back up a clone?

Back up a cannabis clone by keeping two clean mothers in two locations, holding a slow-growing clone line as a living spare at about 18–22 °C under 100–200 µmol/m²/s, and banking the genotype in tissue culture, where meristem culture also helps clean infected stock. As extra insurance, make honestly labelled S1s or crosses, which preserve the clone's genes if the plant is lost.

Can I transplant a clone with only one root?

You can, but it's risky. A cannabis clone with a single short root can't yet supply its leaves, so it often wilts once it leaves the dome and stalls in the new pot. Wait a few more days until several white roots show at the plug's edge. If you must move it, keep it under the dome at high humidity for another 3–5 days.

What size pot should rooted clones go into?

Put rooted cannabis clones into a 0.5–3 L pot first, roughly 2–4 times the plug volume, then into the final pot later. A small pot wets and dries in step with a small root ball. Going straight from a plug into a 20 L pot leaves most of the medium rootless and wet, which slows growth and invites root disease.

Sources

Raviv M, Lieth JH, Bar-Tal A (eds), 2019. Soilless Culture: Theory and Practice, 2nd ed. Elsevier (container size and air-filled porosity). doi.org/10.1016/C2015-0-01807-5

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

Monthony AS, Page SR, Hesami M, Jones AMP. 2021. The past, present and future of Cannabis sativa tissue culture. Plants 10(1):185. doi.org/10.3390/plants10010185