Terms and Conditions

And another thing .....

13 Jan 2013
Seed Potatoes
Seed potatoes are now becoming available in garden centres etc. Don't wait too long before getting in your seed tubers......(more)

13 Jan 2013
The supply of peat
The wet weather during 2012 has restricted the supply of peat for the coming season and as a result prices for peat-based growing media (multi-purpose composts etc) will probably increase......(more)

Peat - the BIG issue

Should you use peat? Are peat-free composts as good as peat-based composts? Are you, like us, tired of seeing that headline 'For Peat's Sake'? As usual, you'll easily find masses of misinformation about peat and the alternatives - but not too many facts.

General information on peat and peat alternatives

Why is peat favoured?

Peat contains very little nutrient, is light in weight, almost sterile, has been fully researched as a growing medium and, as a result, can be 'formulated' with a range of different fertiliser additives for a range of uses. It holds about the right amount of water and air for roots to develop. Peat is readily available in large quantities - if you have any doubts ask a Canadian or a Finn. Special peat areas forming rare wild life habitats are now generally protected and extraction from these sites has been stopped or is being sharply reduced.

What are the nearest alternatives?

Water (hydroponics) Plants need a balance of nutrients dissolved in the water for normal growth. ‘Organic’ fertilisers (ie materials derived from living organisms) usually need to break down into either simple organic chemical molecules (ie compounds based on carbon) or into soluble inorganic chemicals before they can be absorbed and utilized by plants.

Composted bark or wood waste Many of the peat-free composts or 'peat-reduced' composts use composted bark or composted wood waste. Proper composting is essential to produce a good growing medium. In general, a proportion of up to one third bark can be mixed into a compost without problems. Bark and wood waste tend to produce a very free-draining compost. Composting adds costs to the production of bark and wood waste.

Coir Coir dust is produces as a waste from the coir fibre industry and is mainly composed of the pith which holds the fibres together in the coconut husk. Coconuts will grow in salty soils and can contain high levels of sodium chloride. As a consequence the coir dust used for growing plants also can also contain high salt levels. Low salt coir dust is however an excellent growing medium and was widely used in the UK before the introduction of locally sourced peat. Coir dust is normally stacked outdoors to allow leaching and ageing before being compressed into blocks for transport.

Other alternatives Many other materials can be used but there are very few other cost-effective materials which can be directly substituted for peat in growing composts and which are available in sufficient quantities. See below for comments on composted green waste.

When should peat not to be used?

Peat is sometimes recommended as a mulch or for addition to soil especially when planting shrubs and trees. Not only is it a misuse of peat but it has been shown that it can be detrimental to plant establishment. Composted waste used in moderation makes recycling sense and is probably a better material. If soil has good structure there is no need to add anything.

Why not use composted green waste?

Some compost wastes can be used as a component of growing media where there is scientific control of the composting process and proper analysis of the end materials before use as, or added to, a growing medium.

Tests with peat and peat alternatives

Test 1: Impatiens (Bizzie Lizzies) in peat and peat alternatives

We have grown two Impatiens varieties, Expo Select and Fanciful Tropical, in a well-established multi-purpose peat compost and in five mainly coir and bark-based peat-free alternatives. The composts, bought in the UK in spring 2002, were filled into small square plastic pots and planted with plugs of the two varieties. The results showed that some of the peat-free product are as good as the peat-based product but some are not and one could be disastrous!

The plants were kept on through the season and only water applied (no fertiliser) to see how the plants survived into summer.

Test 2 Sunflowers: in a peat vs peat-free 'six-a-side'

We have set six peat-based composts against six peat-free composts in a test to exhaustion! Giant Single sunflower seeds provided by Unwins Seeds were sown in a low nutrient compost and then transferred (July 3) to pots containing each of the peat and peat-free composts. Pots are 13 cm diameter, each holding 600 ml compost (about a pint), and placed in a large saucer. Only water is supplied to the plants. The object is to see which compost grows the tallest or the biggest sunflower plant and to compare the two 'teams' of six.


Test 1 Results

Expo Select in multi-purpose peat compost on the left and in five mainly coir and bark-based peat-free alternatives
Variety of Impatiens Fanciful Tropical shows more colour than Expo Select at this stage but a similar result for peat and the peat-free composts
At later stages one peat-free looks to be providing better longer term growth than the peat-based standard.

Test 2 Results

Sunflowers: in a peat vs peat-free 'six-a-side'

The height of the plants (soil surface to topmost leaf edge) was measured on 31 July and again on 12 August, and 21 August, on September 13 the stems, leaves and flowers of the sunflowers were collected and weighed.

Tips for buying and using growing media

Testing a range of peat-based and peat-free multi-purpose composts with busy lizzies and with sunflowers has given us a good look at what is available to UK gardeners in 2002. Most gardeners use a 'compost' at sometime of the year so perhaps a few tips on buying and using 'composts' is in order.

But first, we need to explain the use of the word 'compost' (as in 'Potting and Bedding Compost'). From now on we will use the word 'compost' to mean a material produced by composting organic matter. Peat, non-peat mixtures and other materials used for growing plants will be called growing media. Un-amended garden compost is not usually suitable for use as a growing medium for most plants - it can, for example, contain either too much total nutrient or unbalanced individual nutrients - and it will usually produce more than a few weeds.

On choosing a growing medium

  • Until more information is available buy peat products from 'reputable' sources - we have seen in the trials how the quality of different peat products can vary. If a plant fails to grow properly in a particular product, try changing brands.
  • Most growing media are best used when fresh, shortly after purchase.
  • Peat-free growing media are likely to be less stable than peat-based products so be careful if you want to use last seasons material. Use up old material as a mulch or soil improver or, better still, spread it on the lawn just after mowing.
  • Read the label to make sure it is fit for the intended use. Some products, including some multi-purpose composts have too much nutrient to be suitable for seeds and cuttings.

Mix and match

  • Mix peat and peat-free to reduce peat use and possibly get a better product than either used on its own.
  • Add grit, sand or soil to either peat or peat-free products used in containers to increase weight and stability and provide a better growing medium.
  • Add controlled release fertiliser granules if you dilute a medium with grit or sand and compensate for the dilution and to provide long term feed for plants.

Be wary of 'multi-purpose' media

  • They can have too much nutrient for seeds and cuttings and not enough for longer term plant growth
  • Use as a base for mixtures because most products will contain balanced nutrients and all necessary trace elements
  • Add grit, sand, soil, coir or composted bark to produce different mixes for different purposes.

To reduce use of peat

  • Do not add peat when back-filling soil round newly planted trees and shrubs. It has been shown to do more harm than good.
  • Do not use raw peat as a mulch unless you want to increase soil acidity.
  • Try mixing peat and peat-free growing media together 50:50 or 60:40.
  • Try peat-free with specific plants. Fuschias, for example, can grow better in peat-free.
  • Use garden compost for mulching.
  • If garden compost is based on fully composted bulky plant material (leaves, grass clippings etc) you can half fill large containers before using a proprietary growing medium as the top layer.

Getting the best from the alternatives

  • Try different products, the tests show how much they can vary in quality.
  • Take time in switching over, peat-free products use a wide range of materials and vary considerably in their properties from each other and from peat.
  • Peat-free products tend to be free-draining and they can become dry very quickly and allow plants to wilt and die. Lift pots to check weight to help decide when to water.


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