What type of soil holds water the best?
Written by
Nguyen Minh
Reviewed by
Prof. Martin Thorne, Ph.D.Clay soils are generally the best at retaining water because they have very tiny particles. As a result, they have a tiny surface area for water adhesion. Here in Utah, I deal with heavy clay in my garden, and I have created puddles that have lasted for days after a rain event. However, that retention creates issues for the plant roots, which need oxygen.
Clay Soil
- Particle size: <0.002mm diameter
- Water retention: High (holds 40-60% moisture)
- Drainage speed: Very slow (hours to days)
- Improvement: Add gypsum for structure
Loam Soil
- Particle size: Balanced mix
- Water retention: Moderate (holds 25-35% moisture)
- Drainage speed: Medium (minutes to hours)
- Improvement: Maintain organic matter
Sandy Soil
- Particle size: 0.05-2mm diameter
- Water retention: Low (holds 10-20% moisture)
- Drainage speed: Very fast (seconds)
- Improvement: Incorporate water-holding amendments
Loam soils are just right. They are approximately one-third sand, silt, and clay. The mixture retains just the right amount of moisture and drains readily. My vegetable garden is planted in loam that allows water to readily reach the roots without causing them to become waterlogged. You accomplish this with consistent organic matter inputs.
You can test your soil using the simple ribbon method. You roll moist soil between your fingers and notice the soil clays out into long ribbons. Sandy soil crumbles immediately. Loam produces short ribbons but then breaks. I teach this in my local gardening classes, and I help everyone identify their soil type within seconds.
Enhance sandy soils using moisture-retaining material. Coconut coir retains 8x its weight. I mix it into my raised beds every spring. Combine with compost for nutrition. Sandy soil is quick-draining; do not overwater. It drains so quickly that nutrients will wash out before roots can uptake them.
Read the full article: 7 Proven Water Retention Soil Methods
