Back to Basics: The Need for Well-Draining Soil

The objective: loose, well-draining soil. Photo by Lise Jenkins


By Kit Flynn and Lise Jenkins

This past winter, I began to think that it would never stop raining. Now, rain can be a gardener’s best friend, but a rainy winter can ruin a garden. How can that be? After all, aren’t many of our plants sound asleep in winter?

Whenever I give a garden presentation to a group, I invariably mention the need for well-draining soil: It’s remarkable how this news creates yawns and glazed eyes. Yet, with each presentation, I feel obliged to impart this information.

So much of good gardening requires referring back to basic gardening rules. These rules aren’t complicated, yet, in the quarter-century I have happily spent gardening, I still occasionally have to remind myself of them. One of these rules is that most – not all, but most – plants require well-draining soil.

The plain truth is that plants need water when they are growing, but they need far less of it while they are slumbering. Yes, there are plants that can flourish in rain gardens. Just remember that most plants thrive better in well-draining soil.

Plant roots need not only water but also oxygen. This is the reason compacted soil is so detrimental to plants. This is also why standing water is so damaging. Submerge roots in water for a sufficient amount of time, and they will do what we do in the same situation: They will drown.

Much of North Carolina’s soil is clay-based. Clay contains very small particles that can easily clump together when moistened, thereby preventing oxygen penetration. Clay soils retain moisture, a boon during hot summer months when rainfall is sporadic, but this can be deadly in a winter such as the one we just experienced.

When I was researching bulbs and geophytes for a presentation, I found no examples that didn’t require well-draining soil. In a saturated soil, geophytes (bulbs, corms, rhizomes and tubers) will rot away. Young plants that have not had time to develop an extensive root system will give up the ghost.

How do you know if your soil is well-draining? Observe it after a good rain. Are there any puddles? Does the soil feel squishy under your feet? Dig a hole one foot deep, and fill it with water. If the water fails to drain within 30-40 minutes, you can assume you have a drainage problem.

Now the obvious question is, “How do I achieve well-draining soil?” First, never add sand to your clay soil. Doing so creates cement, and what you want is a nice loamy soil. Second, the answer lies in adding organic matter – and by “organic matter” I’m talking about compost.

Starting about 15 years ago, I began to spread a commercial compost over the whole garden area. I use a commercial compost because I cannot create enough compost to cover the garden. I then covered the compost with a 2-inch layer of aged wood chips. Some gardeners prefer hardwood chips, while others opt for softer pinewood chips. The choice is yours.

Gradually, I built up the organic layers of soil. The mulch disintegrated slowly, mixing with the compost. This allowed the water to wend its way through the 6-inch layer of loamy soil, gradually spreading out into the clay layer beneath it.

Today, while my neighbors complain about all the puddles in their yards, I can honestly say that my garden is virtually puddle-free, thereby giving me hope that the excessive winter rains have managed to spare my slumbering plants and shrubs.

If you made it this far through this article, without glazed eyes, congratulations, as this shows you’re well on your way to becoming an experienced gardener. It truly is all about following the basic rules.

Absent from their gardens, Kit and Lise enjoy roaming our region exploring the intersection of horticulture and suburban living. More on Instagram @AbsenteeGardener or email:

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1 Comment on "Back to Basics: The Need for Well-Draining Soil"

  1. There are many plants that tolerate, even thrive, in clay-heavy soils. Many of our native North Carolinian plants, such as butterfly milkweed and rattlesnake master, will do better in clay soil with good sun exposure than in rich, well-drained soil. Keeping clay soil will make undesired invasive plants less of an issue, and the water-retaining properties of clay come in handy when we experience drought. This article seems more geared toward traditional European plants like the bulbs mentioned. This is fine if that is the kind of garden someone wants to grow, but it is certainly not the only way. Refusing to “amend” clay soils is also more sustainable and less likely to cause erosion.

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