Soil in bulk bag

How much compost or soil do I need?


If you’re planning a garden project and aren’t sure how much soil or compost to order you’re not alone. We’re regularly contacted by customers in a similar position. Here our team share some guidance to ensure you order the right amount.

If you’re questioning how much soil or compost to order, the likelihood is you’re planning a decent-sized project. Filling pots for summer bedding or topping up the veg bed can usually be handled with a few retail bags from the local garden centre in the car boot. But other projects might mean you need larger, bulk bag quantities or specialised mixes, which can’t be found in garden centres or retail outlets. 

Because our products ship in handy bulk bags that typically hold between 700 and 1000 litres or full pallets of 40-litre bags, it’s understandable why you want to make sure you end up with the correct amount. And there’s nothing worse than underestimating and wishing you’d just ordered that little bit more!

Here we answer some common questions and take you through the process of working out how much you need to order.

What do you need the soil or compost for?

Where and how you’re planning to use the soil or compost is key when estimating the correct number of bulk bags you’re going to need. If you have a new raised bed, for instance, you’re going to need to fill it. Raised beds have specific dimensions, making them easy to calculate. However, if you’re top dressing beds and borders or using one of our products as a conditioner to refresh existing soil, it’s slightly harder to calculate the exact amount – but not impossible!  

Raised beds and defined areas – if you know the dimensions just calculate the volume by multiplying width x length x depth. For example, a 2m wide bed, which is 1m long and 0.5m deep will be 2 x 1 x 0.5 = 1 cubic metre. Our bulk bags tend to be just under 1 cubic metre each but not all bulk bags are the same, so check before you buy.

Lawns – the same calculation works for areas of lawn and laying turf. You’ll need up to 10cm of fresh soil underneath your turf. Therefore, measure the space to be turfed and then use your desired/required base layer measurement as the depth e.g. a 10m x 5m lawn with 10cm of base layer would require 10 x 5 x 0.1 = 5 cubic metres.

If you’re refreshing beds and borders, or digging in as a soil conditioner, the same measurements work, but we’d recommend that you calculate the amount as a series of square metres and then vary the depth value based on the amount you want/need to dig into the soil.

spade with topsoil

What product do you need?

Whilst a bulk bag will be just under 1 cubic metre, what this holds in terms of litres can vary and that is because of the volume of the product itself. Superfine topsoil packs more into the space than wood chips or even some of our mulch products that consist of larger, lighter, looser material.

Although the dimensions of the bulk bag remain the same and will line up with the dimensions you have calculated, the overall volume will vary by product.  

Round up, not down

If you’ve calculated that you need 1.4 bulk bags you may be wondering whether to opt for 1 bag and lay it a bit thinner or have a lower depth in the bed, or go for 2 and have some leftover. Whilst you may expect us to recommend ordering 2 it’s not just because we want you to buy more. It’s because we’ve all been there and in hindsight, we’d all have gone for that second bag! Also, avoid using standard maths rules of rounding up from 1.51 and beyond. If your calculation is any more than a fraction over a full bag, we’d always recommend rounding up and getting the next bag.

Soil will also settle and contract over time, so having more than you may think you need means you can top up once this settlement has happened. Alternatively, use the extra elsewhere – perhaps consider this before ordering and look at whether you need to top up other areas.

The main reason for making sure you have more than you think you need is the feeling of regret. So, save yourself from buyer remorse and round up, not down.

raised bed

Do I need a bulk bag or multiple retail bags?

Another query is whether it’s more economical to buy retail bags from a garden centre or get a bulk bag delivered. There’s a point where both are viable. However, this assumes you have the means to get to a garden centre that sells a quality product and can then transport the individual retail bags home, especially if you need larger quantities. The more journeys you have to make the less cost-efficient this becomes. This is usually when the crossover into bulk bags becomes more cost-effective and easier.

Most retail bags hold 40-50 litres. On a like-for-like basis with our premium-graded products, you’ll probably pay around £18-20 for three bags of garden centre retail compost (typically on a multi-bag offer).

For compost, a typical retail option is 50-litre bags on a 3 for £20 deal. To compare with a bulk bag you’ll need 15 bags or 5 offer batches costing around £100. Compare this price to our bulk bag of beds and borders compost at £110. The difference is transportation and your time to move 15 bags from the garden centre to home, especially when a bulk bag can be delivered kerbside to your home at no additional cost. And volumes beyond this will likely require multiple journeys to the garden centre – adding more time and effort for you.

So, the rule of thumb is that beyond 9 or 12 retail bags, it starts to become more efficient to get one bulk bag delivered – both in terms of time and cost.

Earth Cycle online bulk bag calculator

Thankfully, our clever website chaps have created our bulk calculators. We’ve got one for bulk bags and one for turf. These help you find out how much you’ll need, by product, and the ability to complete your purchase quickly for the exact amount.

If you’re still in any doubt, just pick up the phone and speak to a friendly member of our team who will be able to help you choose the right product and volume for your project.

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