Substrates & Growing Media — Propagation

Sowing and taking cuttings needs three things, and most failures come down to one of them missing: something to root into, something that gets rooting started, and an environment that stays damp and warm until roots appear.

What you root into

Agra-wool Speedgrow are rockwool plugs in a tray: inert, so you decide exactly what the cutting gets, but they do need soaking to the right pH first. How that works is under Rockwool. Growth Technology Clonex Root Riot is the peat-based alternative, as a tray or a refill bag, and it needs no pre-treatment. Both exist for the same reason: small enough that a rootless cutting is not sitting in too much wet substrate.

Gel, powder and mist are not the same thing

This is where it most often goes wrong. Clonex rooting gel and Rhizopon Chryzotop powder both go on the cut itself: they put rooting hormone exactly where the roots need to form. Gel also seals the wound; powder is the dry version and clings less easily to a wet stem. Clonex Mist is something else entirely: a leaf spray for the window in which the cutting has no roots and can only take up through the leaf. Mist on the cut does nothing, and gel on the leaf does nothing either.

The environment is the third part

A cutting transpires through the leaf while it can take up nothing, so without a lid it dries out before roots form. Garland supplies the High Dome propagators in two sizes and the Ultimate self-watering kit, Fertraso the Propagator Pro 70 and Plagron the Seedbox. Do not put them under full light: this stage is about moisture and warmth, not intensity. Plagron Seedbooster Plus is for the seed itself, at germination.

Frequently asked questions

Gel or powder, which works better?
They do the same job. Gel is easier in practice because it stays put and seals the wound; powder goes further. What matters more than the choice is a clean angled cut treated straight away.

When can the lid come off?
Once the cutting is visibly rooting and stays upright without wilting. Wean it by opening the vents in stages rather than pulling the lid off in one go, or it collapses anyway.

Should I feed a cutting?
Barely. With no roots there is nothing to take up with, and too much feed in the plug works against you. Start lightly once roots come through; what is made for that is under Roots.