Peat free growing
If you buy a growing medium, such as potting and seed compost, it’s worth choosing with care. You need a free-draining compost that also holds nutrients.
Up until a few years ago, peat was considered the best option. Now we know better.
Garden Organic urges you not to buy peat compost. Read on and we tell you why, as well as offering alternatives.
We can help you make your own homemade growing medium by mixing compost, loam (soil) and other ingredients. It's not difficult, and we can help you create the right mix for your pots and plants. So there is no need to buy a bag ever again.
What is peat?
It is a type of soil made up of waterlogged, partially-decomposed plant material (including sphagnum moss and other acid-loving plants), which has built up over nearly 10,000 years in wetland habitats.
Why shouldn’t we use it?
More than 95% of lowland bogs in the UK have been destroyed or damaged, in order to gather peat on a large industrial scale. This totally destroys vast habitats which have taken centuries to form. They cannot be regenerated - they are gone for ever. (It takes a year to create just 1mm of peat.) These habitats support many rare and endangered species of plants and wildlife as well as birds, butterflies and dragonflies. Not only is the peat extracted, but the land dries up and the remaining bog dies.
Interestingly, peat provides very little nutrient for plants. It is also not effective as a mulch because it tends to dry out and blow away.
Garden plants don't actually need peat, whereas bog plants growing in the wild do.
So, what should we use instead?
It depends on what you are growing. When filling your flowerpots and containers, you can have fun creating your own ‘soil’ mixes, so long as you have your own source of compost, top soil (loam) and leafmould. (To remind yourself how to make compost, see How to Compost.) The ideal growing medium for containers should
• Provide the correct nutrients for the plant. • Retain moisture, but drain well. • Retain air, yet hold plant roots firmly. • Be uniform in consistency, eg no large lumps, etc. • Be free from pest, disease and weed seeds.
It should not
• Reduce in volume, leaving pots, trays and containers half empty. • ‘Slump’, becoming compact and airless. • Become drained of nutrients very quickly or be too rich for young seedlings
Here below are the best mixes for growing mediums
Sowing seeds Seeds contain their own nutrients so they will germinate successfully in low nutrient material, with good drainage. Recommended mix: 1 part loam (garden soil), 1 part leafmould, 1 part horticultural sand.
Potting on Seedlings and young plants need excellent drainage and a little more nutrient (not too much, or they become leggy without finding their own strength). Recommended mix: 1 part loam (garden soil), 1 part leafmould, 1 part sieved garden compost.
Cuttings These need excellent drainage (so their ends don’t rot) and fine textured medium (to help the roots establish). Recommended mix: Half sharp sand and half home compost (or purchased peat-free growing medium such as coir).
Planting herbs Sage, thyme and marjoram all need a well-drained soil. It is the wet, not the cold, that will kill their roots. Recommended mix: 1 part loam (garden soil), 1 part home compost, 1 part sharp sand.
Large containers Plants growing for a long time in pots need a good source of slow release nutrients.
Recommended mix: 1 part loam, 1 part compost. It is good to feed at certain times such as blooming and fruiting – use a foliar or liquid feed. See how to make Comfrey tea.
If you do need to buy a bag of what the garden centres call compost, make sure it is ‘peat free’ medium. These have improved hugely over the past few years, and many are now outperforming the peat products.
Check the labels – reduced peat means there is still peat there, sometimes as much as 90%. Ignore claims of ‘not from an environmentally sensitive site’ – all peat bogs are sensitive habitats. And organic doesn’t necessarily mean peat free.
Garden Organic advisory sheet Making potting mixes
Natural England's factsheet on peat bogs