How to improve shop-bought compost

How to improve shop-bought compost

Penny Haslam Guest Blog

How to improve shop-bought compost

Guest blog by Olivia Ball from
How to improve shop-bought compost

There is no question that homemade compost is always the better option if you have the choice. For many gardeners the time, space and resources needed to create compost is a luxury and not always possible. For most, cheap shop-bought compost is the only option. Unfortunately, you get what you pay for with compost and cheap shop-bought compost generally lacks in quality. In this blog, we will cover 4 ways to improve shop-bought compost. 

The difference between shop-bought and homemade compost

More often than not homemade compost is better than shop-bought compost for many reasons. Homemade compost, when properly prepared, is full of a range of materials from multiple sources that all contribute to nutritionally balanced compost that will feed plants. Furthermore, you know exactly what is in the compost and you can confidently use it knowing that it is not going to be contaminated. The downside of making your own compost is that it is hard to consistently make good quality compost. The exact contents of homemade compost will vary year on year. Many gardeners struggle to find enough material to make enough compost, not to mention it is a lengthy process.

Shop-bought compost is by far the easier option. It is ready to use and, in some cases, you don't even need to leave your home to get it. A high quality, peat-free compost can even be better than homemade compost as it is made by experts. The problem with this is it usually comes with a big price tag. Cheap shop-bought compost is easily accessible and of course, inexpensive. The issue however is it can be less reliable. It is not always apparent what cheap shop-bought compost is made from or what it has been exposed to and instead of improving the nutrient content in your soil, it can in fact make it worse. Find out more on what gardeners should know before buying compost here.

How to improve the quality of shop-bought compost

Homemade compost 

If you have some homemade compost available, but not enough to use across the entire space, it is a good idea to mix it with shop-bought compost, rather than using them separately. Homemade compost takes around 7 months to decompose so prepare now for next year if you don’t have any available. Mix together equal parts homemade and shop-bought compost and use as normal throughout your garden.


Well-rotted manure is a great way to improve the quality of shop-bought compost as it is full of essential nutrients plants need. Mix 20%-50% homemade compost with shop-bought compost and use as normal. It is important that manure is taken from a reliable source to ensure your plot is not contaminated with any chemicals, pesticides, or antibiotics. 


If you need compost for setting seeds, vermiculite is a great addition that you can add to your compost to improve the chances of germination. Vermiculite is a natural mineral that improves soil structure, increases aeration and improves water retention. For seed germination use fine vermiculite and mix with equal parts compost. 

Organic compost improver

Another way to improve shop-bought compost is to use an organic compost improver such as Envii Compost Probiotic. Envii Compost Probiotic improves the quality of shop-bought compost using beneficial bacteria and seaweed and aids in decontamination. The beneficial bacteria help to break down the larger pieces of organic matter in the compost while the seaweed adds nutrients that will benefit plants.  

Bonus tip: Sieve shop-bought compost to remove the large pieces of organic matter. Through the larger pieces into your compost heap if you have one. 


About the author:

Envii are a UK, family run business that use high quality ingredients to help you grow, clean and protect your home and garden.