With so many different companies claiming to sell premium quality topsoil, it can be a challenge to discover which provider is offering the best value for money whilst also ensuring that the soil being bought is actually superior to the existing already in the ground.

Preparing bought-in topsoil for turfing.  This type of soil would be great for  growing grass but couldn’t be used for topdressing a lawn, for potted plants or as green roof substrate

The first thing you should determine before purchasing topsoil is what you will be growing in it. With this in mind, you can work out the screen size, quality and delivery method (all explained below) that meet your requirements.

What is screened topsoil?

Screening topsoil is the process by which larger clods of soil, stones, roots and other matter are removed from the soil and is done according to size (so soil screened to 1” will contain no lumps or objects more than 1” across). The smaller the screening size, the finer the texture of the soil will be and, usually, the higher the price.

Screened topsoil is free from large stones, plant roots and other debris.  As a rule of thumb, 20mm screened soil is just right for general landscaping

With this in mind, it only makes sense to pay for soil screened to the size you need, and this varies depending on what the soil will be used for. For example, when laying turf, topsoil doesn’t need to be as finely screened as that used for topdressing lawns.

Where does topsoil come from?

It is also wise to check with the supplier that all of the topsoil you will be buying comes from the same source, as well as establishing what that source is.

Many suppliers get their soil from building site excavations which, as well as leading to potentially infertile soil, means that the soil type can vary from site to site.

For small quantities, this won’t pose much of an issue as all the topsoil is likely to have come from the same site, but for very large orders, or orders delivered over a longer period of time, you might end up with different soils leading to a garden with uneven growth.

As well as affecting consistency, the source of topsoil will impact on a soil’s quality and fertility. You should therefore find a supplier with the right product for your needs. The most fertile soil isn’t always the best, with plants such as MeadowMat necessitating poor quality soil if they are to survive.

What size soil bags are the best? 

The final consideration should be how you want to have the soil delivered. The most common options are in sandbags, bulk bags (of 0.5 or 1 tonne) or loose.

A “big” builder’s bag of soil generally weights around 1 tonne and holds 0.8 cubic metres of soil.  Measuring soil by volume is more helpful than by weight as wet soil is a lot heavier than dry soil

Having soil delivered loose is only practical for very large quantities and requires plant to move around. Therefore, for gardens, sandbags or bulk bags are best and the choice between the two is mostly down to how much soil is to be delivered.

The best way to ensure you choose the right topsoil, and can be sure of its suitability, is to buy from a reputable supplier.