Texture and Structure

Soil texture and structure can be modified by using soil conditioners. Soil conditioners act to improve soil aeration, drainage, moisture-holding capacity and tilth, or workability, of the soil. Commonly used soil conditioners include compost, peat moss, sawdust, wood chips, composted animal manures, green manure crops, coarse sand, and perlite. By incorporating coarse, rather than fine sand, and organic matter into a garden soil, the gardener can, over time, produce a desirable loamy-type soil. The addition of fine sand to some soils, especially clay, however, will be detrimental to the soil structure.

A common mistake made when attempting to improve garden soil is failing to use enough soil conditioning materials. For chiefly clay or sandy soil, large amounts of conditioners must be used to effectively improve texture and structure.

Condition the soil by applying 3 to 4 inches of organic matter and, if available, 1 to 2 inches of coarse sand uniformly over the surface of the garden. Till or spade the material thoroughly into the top 8 to 10 inches of soil.

I’d say you are right on track with the hard pack. It’s probably crushed blue stone or something similar. Over time it will be like cement. You’ll need at least 3-4″ of the stuff and it probably wouldn’t hurt to put it over some 3/4″ crushed stone to help with drainage. You can also use a good packing sand. Rent a compacting machine to ensure there are no soft spots. Make sure you get it leveled so it does not pool water. If there is potential for a water issue, then the crushed stone with some perforated drainage pipe (black corrugated pipe. Comes in 100′ coils. If supported on both sides by stone you can walk on it). I’m trying to cover some of the issues you might have. If you are near a slope that might drain water to the area, then a drainage ditch or pipe in some crushed stone to catch the run-off would be a good idea. What you don’t want is this stuff to be constantly wet underneath. I don’t know if the turf product you are looking is permeable and will let water run through it. If not you might consider drilling small holes in the turf to allow for drainage also. All this is speculative because I can’t see the site and I don’t know the product. Your soil conditions are not real conducive to good drainage so for me that would be a prime consideration. I hope this helps. Please feel free to update me or ask more questions. – Steve