Gardening, Grow Your Own, Organic, Planting

How to Propagate (and use a propagator)

Propagation is the art of growing from seed or plug, usually out of season or at least out of the ground or a full-on planter. If it doesn’t involve a greenhouse, it definitely involves a propagator.

A propagator is almost like a mini-greenhouse, made of a tray (either divided into cells or open, and holey or not) and a clear lid. The tray holds the plants, while the lid lets light in while keeping your plants humid. Using a propagator you can carefully control your plants’ temperature and moisture levels, while giving them an unseasonal environment to help them start growing sooner.

But how do you use one?

  1. Fill your tray
  2. Placement
  3. Management
  4. Planting

Feel like we’ve missed a step? Check out our guide on how to sow seeds and plugs!

Fill your tray

Or pots

Propagator trays can take seeds or plugs, or very small cuttings if you have them. Really they’ll take anything you care to fit in them, but chances are you won’t have a lid tall enough to hold it!

If you opt for an open, undivided tray, bear in mind that you’ll eventually have to separate a bunch of intertwined roots. Plants will fill a space with roots up to their full eventual size, so while a plug might only be 2cm across the eventual plants (and root space) could be ten times that! Better to use a divider, or start from seed and plant out before they get too big.

Or, as in the image above – put pots in your trays.

Find a good place for it

Propagators like the sun, but too much and they’ll overheat unless your lid is vented (which most are). Don’t place it in the shade, but pick a place where morning or afternoon sun will get the propagator to a toasty temperature. While also feeding your plants with tasty light if they’ve got leaves already.

A greenhouse or growhouse shelf is a great spot for a propagator, but you can also use windowsills and other outdoor shelves. Keep it raised up so you can easily manage the lid and plants within Рbending over is for the garden.

Manage the environment

Propagators are great for closely managing and monitoring your plants’ environment, but most aren’t perfect. The majority of propagators (bar electric ones) are ‘dumb’, in the sense that they have the tools you need, but need manual operation to work them.

Get a digital moisture meter to know when to water or vent, and a thermometer will save you from lifting the lid before you should. For both, the level of condensation on the walls of the lid will also give you a rough idea of conditions inside, should you not have those meters.

If regularly watering is proving hard to stay on top of, capillary matting can save you the trouble with a regular supply of water. For temperature, you can either get a heated mat or go all out with an electric, temperature-controlled propagator.

Wait, then plant out

While gardening is rarely completely ‘hands-off’, after a certain time all you can do is wait until conditions¬†outside your propagator are right. If you grow a seedling lovingly to a larger plant, you’ll be devastated if you put it out and a late frost kills it.

Wait until your pants are outgrowing their containers and, check the weather forecast to see if you can go straight to garden or still need an intermediate, pot-in-greenhouse stage. If you’re going to garden, the seasonality of your plant becomes the main indicator of ‘is it ready?’. While if you’re sticking to the greenhouse, you still have a few more weeks before they’ve got to go in the ground.