Garden Soil for Virginia Beds Filled With the Wrong Ground

Most beds that disappoint in their first summer were filled with whatever came out of a hole somewhere else on the property. Subsoil from a footing excavation looks like soil, packs like modeling clay once it dries, and grows almost nothing. On Piedmont ground that spoil is usually heavy red clay from under the topsoil layer; on a low coastal lot it can be sand with nothing in it at all. Neither is a planting medium, and no amount of watering turns one into one.

Why did the bed filled with spoil from the hot tub excavation stall?

Because the plants are rooting into structure, not just into nutrients. Compacted clay subsoil holds water in the wet months and sets hard in the dry ones, so roots get waterlogged in spring and then cannot push through in July. Sandy spoil has the opposite problem: water and anything dissolved in it run straight past the root zone.

What fixes both is organic matter mixed through a soil body. That is what this blend is, and it is why the material for a new planting area is not the same material you would use to make up a level.

Compost through a soil body, and where Top Soil and Fill Dirt take over

This is a soil blend enriched with organic compost, mixed so it is ready to plant into rather than needing amendments worked in first. The compost is doing two things at once: feeding the planting, and opening up the soil body so water can move and roots can travel.

The other two bulk soils on this site have different jobs.

Where a bed is deep, there is no sense in filling the whole box with the blend. Make the lower volume up with Fill Dirt or screened soil and keep this material for the top, where the roots actually are.

Will it hold together over Piedmont clay and on low Tidewater ground?

It depends on what is underneath and whether the water can leave.

On slow-draining clay east of the Blue Ridge, break the interface rather than laying a clean layer of good soil onto a hard pan. Fork or till the top of the clay so roots have somewhere to go, and give a flat bed somewhere to shed, because a bed that sits in a bowl of clay holds water no matter how good the fill is.

On the flat Coastal Plain through Hampton Roads, the Eastern Shore and the river necks, water sits close to the surface and a bed can stay wet for days after a tropical system passes. Raising the bed is worth more there than deepening it.

West of the Blue Ridge, in the limestone valleys, soil is often thinner and rock closer to the surface, so raised construction is frequently the only practical option and the blend is carrying the whole root zone.

How deep does it go in a planter, a new bed and a strip being reseeded?

• A raised planter for vegetables wants enough depth for the crop rather than a standard figure. Deep-rooted summer crops want a full box; salad and herbs manage in less.
• A new flower or shrub bed is usually built by loosening what is there and laying the blend over it, deep enough to plant into without the roots hitting compaction straight away.
• A tired bed being brought back gets a top dressing of about 2 to 3 inches spread over the surface and left for the weather and the worms to work in.
• A worn strip being reseeded takes a shallow dressing, enough to cover the ground and hold moisture around germinating seed, not enough to bury the existing grass.

Fill loose and water it in. Do not compact it. A planting medium that has been pressed down has lost the air spaces that the compost was put there to create.

How many yards for the planters, a dog run strip and a turnaround verge?

Length in feet by width in feet, times depth in inches divided by 12, divided by 27 gives cubic yards. This site publishes roughly 2,000 lb per cubic yard for a blended garden soil, about 1.00 ton per yard, which makes the yard and ton figures close to interchangeable here. Treat the weight as approximate.

• Example, two raised planters beside a hot tub pad, each 4 ft by 12 ft filled 14 inches deep: 48 sq ft x 1.167 = 56 cubic feet each, 112 cubic feet for the pair. 112 / 27 = 4.1 cubic yards, roughly 4.1 tons.
• Example, reseeding a worn side-yard dog run strip 5 ft by 34 ft with a 3 inch dressing: 170 sq ft x 0.25 = 42.5 cubic feet. 42.5 / 27 = 1.6 cubic yards, roughly 1.6 tons.
• Example, planting the verge along a turnaround or parking pad, 3 ft wide and 46 ft long at 4 inches: 138 sq ft x 0.333 = 46 cubic feet. 46 / 27 = 1.7 cubic yards, roughly 1.7 tons.

Those are illustrations rather than gardens that were built. Loose soil settles once it is watered, so a planter filled level to the rim on delivery day sits below it two weeks later. Run your own beds through the soil calculator, then pick a quantity and a delivery date on this page. Delivery is arranged at checkout by ZIP code, so have a tipping spot in mind that a loaded truck can reach, ideally on a hard surface rather than on lawn.