How to Test the Density of Compacted Rocky Soil

Vegetables need deep, loose and fertile growing foundations.

Vegetable and flower gardens come with several very specific needs, regardless of what variety of plant you're growing. The plants need the right amount of sun, water, nutrition and soil, and won't thrive if they don't get it. Most garden plants and vegetables need deep, loose and fertile soil for root growth, aeration and soil drainage, and fail in tight soil that holds water. So what do you do if your soil is rocky and compacted? Dig into it, test it for drainage and then amend it accordingly.

Things You'll Need

• Shovel/spade
• Ruler
• Quick-draining garden soil
• Organic compost
• Pencil
• Paper

Instructions

1. Find a site that gets full sun, where you would like to plant your garden. Dig a hole 10 inches deep and fill it with water. Check the hole again 8 to 10 hours later; if the water has drained away completely, the site has adequate drainage for planting.

2. Dig a hole in your site that is 1 foot deep. Fill the hole with water and allow it to drain, then fill it again. Measure the depth of the water using a hand ruler, and record the number. Measure again 15 minutes later to record the change in depth. Multiply this change by 4 to figure out the drainage per hour. A measurement of 1 to 6 inches of drainage every hour is acceptable for planting.

3. Amend soil that doesn't meet drainage standards before you plant. Use equal amounts of quick-draining garden soil and organic compost to produce a mix of 1/3 natural soil, 1/3 organic compost and 1/3 quick-draining garden soil in the top 6 to 10 inches of the planting site. If the drainage is particularly bad, pile a mixture of 1/2 quick-draining garden soil and 1/2 organic compost to a height of 6 to 10 inches on top of the planting site. This mixture provides good drainage and hearty nutrition for the plants.

References

• Purdue University Department of Horticulture: Growing Perennial Flowers
• Cornell University: Gardening Resources: Soil Basics
• Oregon State University Extension Service: Growing Your Own Vegetables -- Soil Improvement