Outside no. 9

To use or - not to use seed compost?

You may have seen the campaign “For Peat’s Sake” led by Garden Organic to encourage us all to switch to using peat free composts compiled from wood based materials.

‘Peat is the UK’s largest carbon store and is routinely dug up in the UK for horticultural purposes, such as for growing media. Bagged retail growing media accounts for 70% of the peat sold in the UK. When this extraction takes place for rare species of flora and fauna, and negatively impacting peat’s ability to prevent flooding and filter water.’

We are all sorting our seeds ready for sowing, so should we, do we, need a special seed compost? It really is a matter of choice, seed varieties and space!

Many plant and flower seeds are very fine and delicate so if you have space these are sown indoors in warmth. Whereas often vegetables are more robust and sown direct outside. Or you may only have a few precious seeds remaining of a certain variety and want to give them a good start. To coax your seeds into life you need a suitable growing medium and attention to hygiene.

Your seed growing material should be uniform in texture and consistency so as  to:

  • allow excess water to drain away whilst remaining moist
  • contain air spaces for extending root growth
  • provide sufficient fertility and structure to support the seedlings

It needs to be free from pathogens and disease (scrub those recycled pots and trays too before refilling)

Although the new peat-free composts perform well you will notice they have a different texture, which requires some attention to your watering regime.

It is recommended to use loam (soil) based seed compost for hardy perennials that may take a while to germinate and are going to stay outside.

Although a small bag of commercial seed compost will probably be enough for all your pots, if you only have a ‘multipurpose’ compost try mixing your own. Thoroughly mix together one third sieved compost, one third washed sand and one third fine grit for starting off your seeds as they don't require high nutrient levels at this stage. I make my own from sieved leaf mould and sand, but then pot on as soon as the seedlings are big enough to handle.