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I judge quality of soil by how well the plants grow. I grow in several different gardens, checking regularly for plant health and making appropriate adjustments.

One opinion I do have is that the character of the soil is the most significant factor in the health of growing plants - retaining moisture, releasing nutrients, supporting micro-organisms, growing vigorous plants, etc.

At home, my raised beds are from imported and amended (organic fertilizer and compost) soil. They are very loose and drain well, but still they all retain moisture pretty well. Although each developed in its own time frame with different inputs, they appear to behave similarly regarding moisture retention.

If I have a choice I avoid made-up soil. It took three years for my raised beds at home to grow really nice plants.

The Fall City garden has typical Puyallup sandy loam, considered by some to be ideal. It drains well, and still retains moisture well.

My other garden near the Snoqualmie river is mostly clay. It doesn’t drain well at all, but it retains moisture and seldom needs watering.

Steve Solomon has a lot to say about growing vegetables in clayey soil, suggesting that this type of soil requires massive modification. I have been able to grow corn and tomatoes but with much more than normal amendment, mostly with lime (agricultural lime plus dolomite lime), organic fertilizer and homemade compost. I needed to resort to a foliar spray of fish fertilizer to keep tomatoes healthy.

Except in extreme heat, plants in any of the locations I grow require water less often than once a week.

My mentors say that humus from compost and organic matter help retain moisture.