Propagators and Cuttings: How to Root Cuttings and Start Seeds
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, and how to take cuttings that root.
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.
| Propagator | Size | Notes |
|---|---|---|
| Garland unheated, Large High Dome | 37.5 x 23 x 18 cm | For warm rooms and heated greenhouses |
| Garland unheated, XL High Dome | 58 x 40.5 x 22.5 cm | As above, full-size tray |
| Root!t Budget Propagator | 57.5 x 37 x 22 cm | Unheated; takes a tray of 77 or 150 rockwool cubes or 40 Jiffy pellets |
| Garland XL High Dome Heated | XL | Built-in heater with thermostat; high dome and adjustable vents |
| Probox Propagator Small | 60 x 40 x 40 cm | Small box with adjustable vents |
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.
Propagation tents give cuttings a light-tight space of their own. The Secret Jardin DP60 (60 x 40 x 60 cm) has a 10 kg roof, so it doubles as a table; the DP90 (90 x 60 x 98 cm) holds two standard propagators; there is also the DP120. Our propagation tents come ready to go.
What to root in
| Plug | Size | Good to know |
|---|---|---|
| Jiffy-7 peat pellets | 38 mm, swell to 41 mm | pH 5.3 and fully fertilised, so no pH adjusting or feed at this stage; packs of 25, 100 and 1,000 |
| Root Riot cubes | Same size as a 1-inch rockwool cube | Coir with an organic binder, pre-moistened, with micro-nutrients and beneficial fungi |
| Rockwool propagation cubes | 25 x 25 x 40 mm or 36 x 36 x 40 mm | Trays of 150 or 77; pot on into 3- or 4-inch transplanting cubes |
| Plug Life 80/20 peat mix | Tray of 104 | Peat starter plugs |
| Jiffy coir pots | Singles to boxes of 1,100 | Roots grow through the wall, which air-prunes them |
| Jiffy Botanian peat-free pots | 6, 8 and 10 cm | Plant the whole pot - it breaks down in the soil |
Getting Jiffy pellets ready: stand them hole side up in a tray or propagator, add a little tepid tap water to the bottom and let them swell for about 20 minutes. For seeds, make a hole about 5 mm deep, drop the seed in and cover it.
How to take cuttings
- Have everything ready first: a sharp, clean scalpel, your plugs soaked, the propagator set up.
- Take the cutting from healthy, actively growing (softwood or semi-hardwood) growth.
- 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.
- 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.
- Put the plugs in the propagator, lid on. Clonex Mist is a spray for cuttings if you want to mist them.
- 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.
Light for seedlings and cuttings
Young plants want gentle light, not a flowering lamp. Maxibright LED T5 propagation lights come in 60 cm (2 or 4 tubes) and 120 cm (4 or 8 tubes); the Gorilla 12W propagation LED is a 60 cm strip that daisy-chains; the LUMii 55W EnviroGro is a 6500K PL lamp. See all propagation lighting.
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.
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 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
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.