Part 1: Propagation by seed

3. Containers

An empty seed tray

Amber Crowley / public domain

A seedling with roots and soil attached, ready for transplanting.

Pixabay / Licence

Simple, shallow trays with holes in the bottom for drainage.

Pros Cons
  • Quick and easy to fill up with compost.
  • Do not dry out too quickly but drain effectively.
  • Cheap to purchase.
  • Easy to clean and reuse.
  • Once the seeds have germinated their roots quickly tangle with neighbouring seedlings meaning that the roots are disturbed when you prick the seedlings out.
A stack of cell trays in a greenhouse

Amber Crowley / public domain

seed plugs ready for transplanting

Dwight Sipler via Wikimedia / CC BY 2.0

Trays formed with sections in, called cells. Designed so that one plant grows per cell. The resulting seedling with its round or square clump of compost attached is called a ‘plug’ or a ‘plug plant’.

Pros Cons
  • The roots of each seedling cannot get tangled with neighbouring seedlings.
  • The roots are only minimally disturbed when removing the plug from the cell (plug = seedling with attached roots in a ‘plug’ or compost).
  • Dry out more quickly than seed trays.
  • Some less rigid cell trays (when made of thinner plastic) are easily damaged when removing the plugs which means they are not as easily reusable.
  • Sometimes plugs can be difficult to remove resulting in damage to the seedling – plugs should be removed by pushing up through the drainage hole in the bottom rather than pulling on the seedling.
3 stacks of plastic pots

Amber Crowley / public domain

Seedlings in plastic pots

Pixabay / Licence

Individual containers, sometimes put into carrier trays for ease of handling.

Pros Cons
  • A range of sizes available to suit different seedlings.
  • Easily reusable.
  • Cheap to purchase.
  • Dry out more quickly than seed trays if small sizes are used.
  • Can be more fiddly to handle that trays unless in a carrier tray.
  • Take up lots of precious windowsill space!
Seedlings in pots made from empty toilet rolls.

Stacie via Wikimedia / CC BY 2.0

Seedlings in decomposable pots in a greenhouse.

Pixabay / Licence

Individual plant containers made from (usually) recycled paper. They can be hand made by folding paper or toilet roll tubes or bought from commercial suppliers who form them from paper pulp.

Pros Cons
  • Environmentally friendly.
  • Decomposable on your own compost heap.
  • As simple to use as plastic pots.
  • Dry out more quickly than plastic containers as the water evaporates through the pot.
  • Single use so could be more expensive in the long run than reusing plastic pots many times.
  • Sometimes they disintegrate before the seedling is ready to be planted out.
Activity

Research suppliers of seed trays, cell trays and different types of pots online. See how the availability and prices compare. Which would you choose to use if you were to start a commercial propagation nursery?