Propagators and Cuttings: How to Root Cuttings

Seeds and cuttings need warmth, high humidity and gentle light for their first couple of weeks, and a propagator is the simplest way to give them all three. This guide covers choosing a propagator, the starter plugs to grow in, how to take cuttings that root, and which propagation light and tent to use. For sowing, pricking out and hardening off seedlings, see our sowing seeds indoors guide.

Choosing a propagator

A propagator is a tray with a clear lid that holds warmth and humidity around young plants. Heated ones add gentle bottom heat; unheated ones rely on the room.

Heated or unheated? If the room or greenhouse is already warm, an unheated propagator is enough - that's what the Garland unheated models are made for. In a cold room, or for seeds that want warmth to germinate, go heated.

What to root in

Everything in the table below is in our plugs and substrates section.

How to take cuttings

1. Have everything ready first: a sharp, clean scalpel, your plugs soaked (Jiffy-7 pellets: see our sowing seeds indoors guide), the propagator set up.
2. Take the cutting from healthy, actively growing (softwood or semi-hardwood) growth.
3. Straight away, dip the cut end 10-20 mm deep in Clonex rooting gel. Clonex is a gel so it stays in contact with the cut and seals it, which its maker says lowers the risk of infection compared with powders or liquids.
4. Push the cutting into the plug. In a Jiffy pellet, make a deep hole with a cocktail stick first and push the stem about two-thirds of the way down.
5. Put the plugs in the propagator, lid on. Clonex Mist is a spray for cuttings if you want to mist them.
6. As roots form, open the vents a little at a time so the cuttings get used to drier air before they come out.

Want it all in one box? The Cloning & Propagation Bundles put starter cubes, Clonex 50 ml and a sterile scalpel together.

Which propagation light and tent?

Young plants want gentle light, not a flowering lamp, and a light-tight tent keeps that light to itself: the Secret Jardin DP60 page says it can go in a corner of your main grow room without affecting the dark cycle. The quick answer is one of our tent kits. The Cloning & Propagation Tent Kit - Small is a DP60 tent, one Gorilla 12W LED and a Garland propagator; the Cloning & Propagation Tent Kit - Medium is a DP90, two Gorilla 12W LEDs and an XL Garland propagator. Choose by how many cuttings you take: the DP90 holds two standard propagators, the DP60 one.

The 120 cm Maxibright is too long for the DP60 and DP90, and the 58 x 40.5 cm Garland unheated XL too wide for the DP60.

Setting up. On these R4 tents you cut your own 100 mm vents where they suit, with the cutting kit supplied: a flange for the extraction vent and a light baffle for a passive intake. For the extractor, our advice is the 100 mm Air EC Inline Fan, to match the vents: it moves more air than even the DP120 needs, by the sum in our fan and filter guide, and its page says a speed controller is included. If the tent still runs cold with a heated propagator in it, we would add a small Hylite tube heater (28 W or 55 W), whose page names propagation areas and gentle heat but lists no thermostat, so run it on one, with clear space around it, as our heaters guide explains. We would put a ThermoPro TP358 sensor at tray height.

Hours and height. Our advice is 18 hours of light a day, the usual 18/6 vegetative schedule in our growers' glossary. Hang the Gorilla close, as its page allows, and any other light at the height in its maker's instructions (see our grow lights for indoor plants and seedlings guide); our LED wattage guide gives a PPFD of 100 to 300 for seedlings and cuttings. See all propagation lighting, propagation tents and propagation kits.

Quick answers

Do cuttings need feeding?

Not in Jiffy-7 pellets - they are fully fertilised. Root Riot cubes also carry micro-nutrients. Start feeding once roots show and the plants are potted on. For those first feeds, Canna Start is made for juvenile plants, its page says: mix in Canna Rhizotonic or another root stimulant first, then add 2-4 ml per litre (or until the EC is 1.0-1.2) and set the pH to 5.3-6.3, depending on the medium.

Peat pellet, peat-free pot or coir pot: which?

Jiffy-7 peat pellets are the medium itself (pH 5.3 and fully fertilised, as the table says). Jiffy Botanian peat-free pots (6, 8 and 10 cm) and Jiffy coir pots take pricked-out seedlings or a rooted pellet in light-mix soil or coco, and are planted whole when you pot on. Coir pots let water through faster than peat pots, their page says.

Gel, powder or liquid rooting hormone?

We sell Clonex gel because the gel stays on the cut and seals it, where powders and liquids can run off.

When do I open the vents on a propagator?

As roots start to form. Until then keep them shut, so the air stays humid while the cuttings have no roots to drink with. Then open them a little more each day before leaving the lid off for longer and longer until it stays off. If the lid is running with water, open them a touch sooner.

When are cuttings ready to pot on?

When you can see roots coming through the sides or bottom of the plug.

Little black flies around the propagator?

Probably fungus gnats, which love damp plugs. See our fungus gnats guide.

More Growers' Guides

• Sowing seeds indoors
• Fungus gnats (sciarid flies)
• pH and EC meters
• What size grow tent?

Not sure what you need? Call the shop on 0117 971 3000 or pop in to the Bristol store and we'll help you pick.