How much does a bulk bag cover?

A bulk bag holds around 0.7 cubic metres of loose material. Sizes vary a little between suppliers, so always check the stated volume rather than the bag itself, but 0.7 m3 is a fair working figure.

Topsoil weighs roughly 1.5 tonnes per cubic metre, so a bulk bag of topsoil weighs close to a tonne. That is why they often get called tonne bags, even though the exact weight shifts with how wet the soil is.

Bark and woodchip are much lighter for the same volume, so a bulk bag of bark weighs far less than a bulk bag of soil but takes up the same space and covers the same area at a given depth.

Coverage is just volume divided by depth. Take the 0.7 m3 in a bulk bag and split it over the depth you want.

At 25mm deep you get around 28 square metres. At 50mm, around 14 square metres. At 75mm, around 9 square metres. At 100mm, around 7 square metres. At 150mm, around 4.5 square metres.

So the same bag covers four times the area at 25mm as it does at 100mm. Decide your depth first, then work back to the number of bags.

For a new lawn you want 100mm to 150mm of decent topsoil over the subsoil before you turf or seed. At 100mm a bulk bag covers about 7 square metres, so a 35 square metre lawn needs roughly five bags.

For raised beds and planting borders, go deeper, 150mm or more, because roots need the room. A bed one metre by two metres filled to 300mm takes about 0.6 m3, near enough a full bulk bag.

Unscreened economy fill, where yards sell it, is for building up levels and bulking out under a better soil, not for planting straight into. For a lawn or beds use screened topsoil, which is sieved and consistent.

TopTurf sells screened topsoil at £70 a bulk bag, one grade at one price, delivered from Leigh.

For bark mulch on borders, 50mm is about right. That is enough to hold moisture and keep weeds down without smothering plants. At 50mm a bulk bag of bark covers about 14 square metres.

If weeds are bad, go up to 75mm, which drops coverage to around 9 square metres a bag. Any thinner than 40mm and light gets through, so weeds push back up.

Play bark under swings and climbing frames needs to go much deeper for a soft landing, 100mm and up, and more directly under the equipment. Plan for a bulk bag covering only 7 square metres or less at that depth.

TopTurf sells one bark product: premium landscaping bark at £87 a bulk bag, which covers about 14 square metres at 50mm. We do not stock play bark or woodchip, so for a certified play surface use a specialist supplier.

Some suppliers tip loose loads straight off the lorry rather than bagging them. That can suit very big jobs, but you need hard standing for it to be tipped onto and you barrow it yourself.

Bulk bags are tidier, can be set down where there is access and do not leave a mess on the drive. That is why TopTurf supplies everything in bulk bags only: screened topsoil at £70 and landscaping bark at £87.

For a couple of borders, one bag of bark is usually plenty. For a full lawn, order the bag count the coverage maths above gives you, plus a little spare.

TopTurf deliver from Leigh, with delivery from £20 worked out on your postcode and the amount you order.

If you would rather not handle it yourself, ask about supply-and-lay: Barrow Landscaping spreads the topsoil to the right depth and lays the turf straight on top. Order by phone on 0161 399 8706 or email.

It depends on depth. A bulk bag holds around 0.7 cubic metres, which covers about 7 square metres at 100mm deep, 14 square metres at 50mm, and around 28 square metres if you only need 25mm.

Close, for topsoil. A bulk bag holds about 0.7 cubic metres and topsoil weighs around 1.5 tonnes per cubic metre, so a bulk bag of soil weighs near enough a tonne. Bark and woodchip are much lighter for the same volume.

Spread bark at about 50mm to suppress weeds and hold moisture. At that depth a bulk bag covers roughly 14 square metres of border. Go to 75mm on bad weed patches and a bag covers about 9 square metres.