Home Compostable Guide

The differences between biodegradable, home compostable, industrial compostable, and recyclable products.

Firstly we make it clear that all Merlin Growers products are Home Compostable and as such can be broken down in a compost bin in the garden or in the garden soil. This, as far as we are concerned, is the most important aspect of our products. The only other better way is not to buy them in the first place!

We also offer equipment that will mulch our labels, pots and trays into a mulch that retains water and suppresses weeds if you do not want to recycle them.

Our logo which signifies our product is Home Compostable


You might have noticed two different labels on packaging: certified home compostable, and certified commercially compostable. These each refer to the two different methods of composting: at home, or in an industrial (commercial) facility.

How composting works

Composting is a process that breaks down organic matter through the use of fungi, bacteria, insects, worms and other organisms to create a nutrient-dense ‘compost’. This compost can then be used as a powerful fertiliser and soil conditioner.

Industrial composting versus home composting

Both forms of composting create a nutrient-rich compost at the end of the process. Industrial composting can sustain the temperature and stability of the compost more rigorously.

There’s a lot of confusion in the community and online around the difference between home compostable and industrial compostable packaging. There is a difference that can have an important impact on the future of this kind of packaging and for our environment and Merlin Growers wishes to clear it up.

Firstly, compostable packaging originates as an organic substance, such as bamboo, paper or sugar cane. This packaging is classed as either:

1. packaging that will decompose in a home compost bin

2. packaging that requires disposal in an industrial compost facility to properly decompose.

Home compostable

Home composting occurs at a much lower temperature and over a longer time than industrial composting – usually about a year – whereas industrial composting may be complete in a matter of weeks. Everything that goes into making compostable packaging should break down and decompose into organic soil if it is labelled home compostable. This includes the ink, and glue, everything.

Industrially compostable

Industrial composting can deal with a broader range of compostable products and operates in a highly controlled setting with specific temperatures and conditions. Industrial composting is able to apply a far higher temperature to the already pre-processed packaging material. The high heat breaks the packaging down even further, hastening the decomposition.


Biodegradable Plastics

Theseundergo the digestion by microbes to form natural bi-products and what is known as humus (a sludge that makes an excellent plant fertiliser). It also produces gas which is officially known as a biogas. Landfill-biodegradable plastics have patented additives that help it biodegrade naturally in landfills. Once the biodegradable packaging ends up in a landfill, it attracts the necessary microbes that break down the plastic into its natural components.

Fuels Generated During The Biodegradation Process Of Landfill-Biodegradable Plastics

In the deepest areas of a landfill, there is little oxygen available, so the microbes that are there live on hydrogen instead of oxygen. The biogas they give off there is methane CH4 (otherwise known as a ‘natural gas’ in layman’s terms). This is a good fuel and if harnessed and can be used to generate electricity or drive gas powered vehicles etc. If the biodegradation occurs near the top of the landfill or in a managed compost pile where there is plenty of oxygen, then the biogas is CO2 – i.e. carbon dioxide.

Both CH4 and CO2 are vented to the atmosphere unless the landfill operator actively collects the CH4 to be sold. Most modern landfills capture CH4 these days as it is worth money. CO2 emissions are not worth anything and are just vented. Unfortunately, if CH4 is vented to the atmosphere it is a much worse greenhouse gas than CO2 – about 20 times worse. However, it has a short life of about 7 years in the atmosphere until it gets broken down to CO2. Hence why it’s so important to capture CO2.

How To Know If a Product Is Biodegradable

For a biodegradable claim to be accurately made on a product, it should state where it has to be disposed of in order to biodegrade.

Compostable Plastics

Compostable plastics simply undergo biodegradation but under controlled specific conditions. So essentially, the term compostable is a subset of the general term biodegradable. A compostable plastic is made from plants, not from oil. A commercial compost facility requires the material to be tiled (turned over) or have fresh air pumped through the piles to keep oxygen rich.

Commercial Composting Requirements

In a commercial composting facility, the microbes in a compost facility require oxygen. If they don’t get that they die, and no more biodegradation occurs. Also, these microbes require a minimum temperature of 60 degrees Celsius and lots of moisture. If they don’t get those too, they will not survive, and biodegradation stops. So, as you can see, compostable materials require a specific process and environment to actually break down, which is why there are very few commercial compost facilities around.

Why Most Compostable Plastic Packaging Products End Up In Bins and Landfills

There are 28 different recycling labels on plastics.

There is no special transport to pick up compostable plastic and truck it to such a facility. Also, we as consumers can’t be expected to drive hundreds of kilometres to drop off their compostable packaging. Even with branding and labels, there aren’t many special markings on these compostable plastic to tell the consumer whether it is a compostable plastic or not. Hence almost all consumers end up throwing it in the bin which ends up in a landfill where it won’t biodegrade. Even if it was marked as which consumers would more than likely throw it in the nearest bin anyway.

How long does it take for compostable plastics to biodegrade?

There is a compostable standard that dictates that a compostable plastic has to be able to biodegrade within 12 months. With commercial compost, the biogas is CO2 so there is no chance to generate energy from it like it can from methane, which is a lost opportunity.

Home Compostable Plastic Packaging

Alongside commercial compostables, here are home compostable packing products which fulfil the Home Compostable standard. This means these products are also made from plants but don’t need those above specific commercial conditions for it to biodegrade. It will biodegrade in a landfill or a home compost bin. It may take 1-3 years which is still quite fast, but it does not fit the commercial compost standard. The downside of this material is it has a shelf life of about 12 months, after which it becomes weak and starts to tear easily etc. (Merlin Growers would question this statement)

Also, neither ‘Compostable’ nor ‘Home Compostable’ technologies are able to be mainstream recycled. (Merlin Growers would question this statement)

Recyclable Plastics

The term ‘recyclable’ refers to where the used items are sent to a facility where they are processed into a raw media form that a manufacturer can then use to make more products.

Taking the example of plastic bottles, if recycled, they are sent to a regrind facility who grinds them up to chips or powder. Then a bottling maker company may buy those to make more bottles.

Why Most Plastics Can’t be Recycled

However, plastic is not like a metal. An Aluminium can may be recycled to make more aluminium cans a million times. The technical reason for this is a metal is formed by atoms of the metal bonding together. So, when you melt a metal then cool it again the metal atoms just bond to their adjacent atoms again quite happily.

A plastic on the other hand is made of molecules that bond together in long chains of atoms. Generally, chains of Carbon with hydrogen atoms along the sides. When a plastic is remelted some of this structure gets irrevocably damaged and the plastic molecule loses some of its strength (and other) properties. This can only be done 2-3 times before the molecules are so badly damaged that the new plastic product does not have the desired properties any more.

So, recycling of plastic sounds good but the reality is it is only delaying the inevitable to be thrown out. The plastics industry is spending a fortune on marketing recycling, recycling to make people think if they are buying plastic items or packaging that it can be recycled, and all is good. But the industry well knows it does not work and they will keep selling virgin plastic media all the time.


1. Plastic.

Plastic is plastic (even recycled plastic or biodegradable plastic) and is usually made from Oil and whatever it is used for it is and never will be “green”. In some forms acceptable (just) but in other forms and products dangerous to the environment and ultimately us.

2 Industrial Compostable

Industrial Composting breaks down a large number of products and is good but some of the products that can be industrially composted are confused for plastics and defeat their original production and end in landfill or contaminate real plastic.

3 Home Compostable

These items are usually made from organic products. They break down in the natural environment into natural products. This process takes a varying amount of time depending on how the product was originally produced, how it was treated and what it was designed for.

The process to make a home compostable product can be not environmental friendly but for the planet this is probably the best solution.

PLASTIC TAX EXPLAINED (Thanks to Horticulture Week for this explaination)

Under the new Plastic Packaging Act legislation, from 1 April 2022, all plastic items used in the packaging of products must include a minimum of 30% recycled content, or face taxes of £200 per metric tonne of chargeable plastic packaging components.

All suppliers whose products include any plastic component – recycled or not – must submit details to HMRC from April 2022, if the volumes involved meet the 10 tonne per tax year threshold.

Even suppliers who are below the volume threshold would be advised to keep records in case of audit – even if they do not have to pay the tax.

The legislation may affect any home or garden business which manufactures or imports plastic packaging, including ready packaged goods.

Certain single-use products might be categorised as packaging for the purposes of the tax.

This does not include multi-use plastic such as home storage containers, lunch boxes and garden planters and storage.

Carrier bags and plastic cups are within the scope of the tax.

The £200 per tonne tax applied to plastic packaging includes biodegradable, compostable and oxo-degradable plastics made in, or imported into, the UK unless they contain at least 30% recycled plastic.

The requirement on manufacturers or importers to show on invoices the amount of tax paid on packaging will be voluntary at first. The onus will be on businesses to undertake due diligence and to provide an audit trail.

The tax is designed to provide an economic incentive for businesses to use recycled rather than virgin plastic.

The tax has helped drive an increase in investment in recycling infrastructure: 486,000 tonnes of plastic packaging was recycled in the UK in 2020, compared with 384,000 tonnes in 2018.

Double that will be needed to meet stretching recycling targets, according to waste charity WRAP.

Experts can detect the level of recycled content in polypropylene (PP) Recycling number 5, polyethylene (PE) Recycling number 2 and polyethylene terephthalate (PET) Recycling number 1.


What the plastic recycling numbers mean

(click image)

Cardboard chopped and used as a mulch keeping the plants moist and eventually breaking down to a rich humus.

Our products are researched and designed to be environmentally friendly and to break down to a mulch after being chopped.