Peat-Free Composts: The Truth About Buying & Using Garden Composts

Peat-Free Composts, Buying Composts & Making Composts Causes Gardeners Headaches. Many Garden Centres & Compost Manufacturers Make It Hard By Using Confusing Descriptions. Learn More About Peat-Free Composts Here.

Organic, Natural, & Plant Based sound great when we are buying composts. But these are all terms used by the companies that sell peat to make us think we are buying peat-free composts.

The thing is all peat is natural, organic and plant-based. But that doesn’t mean it’s good, or that we should buy it. Peat is formed when plant material, such as sphagnum moss, partially decays in acidic conditions that lack oxygen. In nature, this is in peat bogs that take thousands of years to form.

The problems start when these peat bogs are stripped of their peat as this destroys natural habitats that have taken millennia to form. The fragile natural habitat is destroyed with the loss of plant and animal species. Peat s also a natural carbon sink and, when damaged, releases carbon into the environment.

Banning Peat-Based Composts

Several popular gardening presenters have tried to get us to stop the use of peat. They have faced a backlash from the horticultural industry because peat is still used to grow many of the plants for sale in garden centres. Plus bagged peat it is sold to the public in huge quantities.

In 2010 the government tried to phase out the use of peat in the amateur garden market, by 2020, via a voluntary target. This has failed and when I recently surveyed the sale of peat in local garden centres I discovered all of them were selling peat-based composts.

The problem is that gardeners are still buying huge quantities of peat each year. If we really want peat sales to stop the simplest way to achieve it is to stop buying it. That means each and every one of us has to refuse to buy peat-based composts AND plants grown in peat or peat-based composts. We have the power to stop peat being used.

Why Do Gardeners Buy Peat-Based Compost?

Gardeners often unknowingly buy peat-based composts. They see bags marked organic, natural and plant-based and think that means peat-free. It’s actually very truthful marketing! But marketing that uses words that are honest but misconstrued by a public that often don’t understand enough about gardening and the environment.

I don’t mean that condescendingly. Marketing is full of descriptive words that are used to appeal to our emotions. And we can’t be experts at everything so tend to fall for the marketing that seems to make sense and is in line with our underlying want to be greener and responsible citizens.

What we should be looking for are the words peat-free. Few composts carry them. But unless they do its unlikely that what you are buying is actually peat-free.

The second way we buy peat is in the compost used to grow the plants we buy. Growers still use a lot of peat in their composts and the only way we can check on this is to ask if the composts being used are peat-free. My experience of this is that most employees in garden centres don’t actually know what is in the compost!

If you really want to know if the compost is peat-free I suggest you write to the garden centre before visiting and ask the question. If more of us did this the garden centres would get the message that we are concerned over this and that they will lose sales if they use peat.

Why Do Garden Centres Use Peat?

As an ex-commercial grower, I understand why garden centres use peat! Don’t get e wrong, I don’t condone it. But I do understand it.

The problem is that the alternatives aren’t that good. They are quite variable in nature with nutrient levels that vary greatly from batch to batch. And that’s just the start of the problems they give the grower.

There are alternatives that can be used as part of the compost mix. For example, they can use coir. It’s a natural waste product of the coconut industry and has some benefits, The problem is it is on the other side of the world to us and shipping it here creates a large carbon footprint that the public and government want to be reduced! Transporting coir contributes to greenhouse emissions and global warming. And then there’s the water usage. Coir needs washing to get rid of high salt levels. In countries where clean water is hard to come by this contributes to local problems.

Recycled Waste 

Producing compost from green waste sounds like a good idea for commercial growers. And it is in many respects. The problem is that it leads to an inconsistent product depending on the time of year. Think about the green waste you produce. In summer it most likely has a lot of grass mowings and in winter none at all. That means the nutrient levels in the compose fluctuate with the quantity of grass incorporated in it. Ditto dead leaves and a lot of other constituents.

Wood chip, wood fibre and composted bark are all alternatives often used to replace peat. But none of them are without problems. For example, too much wood locks up the nitrogen in the compost and plants suffer from a lack of nitrogen, which means poor growth!

Too much coir and wood also open up the compost which means it doesn’t retain water. The result is plants need watering far more and that is both time consuming and costly.

Choosing The Correct Composts: Peat & Peat-Free Composts

In short, this isn’t easy. The reason is that we can’t see the nutrients in the compost. However, with experience, we can determine a few things that will guide us as far as it’s possible.

Texture

Clearly, we need a smaller particle size when sowing small seeds or they don’t keep in good contact with the compost. But having said that composts with a fine particle size tend to slump and waterlog. On the other hand, coarse particle sizes tend to dry out much quicker. So think about the compost’s purpose when choosing for specific purposes.

Structure and aeration

This goes with texture. Particle size dictates the amount of air space the compost has. If it lacks air space there is also nowhere for the roots to go. I quite like the composts that have added bracken to provide structure. Over time this breaks down, but fresh compost will likely have the structure needed for its chosen job. Once the compost is recycled it may be necessary to add a quantity of sterilised soil or sand to open the texture back up.

pH levels

So choosing the right compost for our plants is essential in terms of pH. And Kate is right about the availability of nutrients. They are affected by the pH which releases them or locks them up according to the pH affecting that specific chemical. 

Nutrient level

Many composts have nutrients added. Add too much and seeds will fail to germinate or will get root scorch when they do. This is due to a high level of “salts” in the compost. If growing seeds the safe way forward is to choose a seed compost.

Multipurpose or general-purpose, composts are great for just about everything. They have some added nutrients but not too much. You can use them for most seeds or growing plants.

There are also potting composts on sale. These tend to have much more fertiliser added to them, often its slow release fertiliser, and will be released as plants start to grow. This is often achieved by the fertiliser release being temperature dependant. The warmer it gets, the more nutrient is released at a time when the temperature should be boosting plant growth. It’s a crude way of doing it but it works reasonably well.

Growbags are very popular but generally use the compost that isn’t good enough for other uses! The nutrient levels are often poor because the manufacturers expect the grower to start feeding the plant soon after planting.

Compost Inconsistency

Tests by Which? demonstrate that composts tend to be quite inconsistent within a brand. Even within a particular named compost, there were large differences in their trials.

Beware!

Which? has produced a good page of info on Peat-Free growing media 

Compost Prices: Peat & Peat-Free Composts

I can’t put this delicately. Compost prices are often a rip-off.

The bag sizes vary hugely from 10 litre bags to 60 litre bags. They are packed by volume and this will decrease if the bags are stacked high (due to compression and loss of structure) and due to drying out.

I recently surveyed composts in local garden centres and online and tried to make a fair price comparison based on price per unit size. To make the maths easy I decided on a mythical 100 litre bag as being the standard.

Prices, based on my 100 litre bag ranged from £9.60 to an amazingly expensive £79.90 for what were very similar products. In all cases, bulk deliveries of one ton bags were more expensive than collection from a local garden centre. This is to be expected when the delivery was added. The surprising thing was that the extra cost was very small.

What was most expensive were the smallest bags. Often only 10 litres in size they frequently cost far more than the large bags of exactly the same thing that were available just feet away.

I have to confess I looked at buying a few ton bags of compost for my garden from a national supplier. But I could buy what was essentially the same thing from a garden centre with much less hassle and collect as and when it suited me and I was passing the garden centre.

Home Made Peat-Free Compost

Making your own compost isn’t difficult. Organic material decomposes very easily and will soon turn to compost, especially if we help it by providing the right conditions. 

I wouldn’t recommend using homemade compost for seed sowing in most cases as it tends to be inconsistent in texture, moisture retention, pH and nutrient levels. But using it as a mulch or in the No-Dig garden is fine. For winter use I tend to put it onto the beds before its fully decomposed. For example, the compost in the image at the beginning of this post was spread in December and was just eleven weeks old. It was a bit wet and some of the larger twiggy constituents hadn’t fully broken down. But by spring this will be partially incorporated by earthworm activity. Plus the frosts will also help break it down further.  

More Than Peat Free Composts! 

If you want to check the meanings of any of the more technical gardening words check out the Gardening Dictionary  And for more on other gardening topics just browse this site via the links below. 

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