Gardening in Sandy Soils

sandy soil

Introduction

Sandy soils must be managed differently from other soils to ensure healthy plant growth. Sand-dominated soil textures include loamy sand (at least 70% sand) and sand (at least 90% sand). Soil texture can be determined by a soil test (see http://www.usual.usu. edu/ for more information on soil testing in Utah). Generally, soils that contain greater than 70% sand are considered unacceptable as topsoil material due to poor water and nutrient retention capacities. 

What is Sand?

Sand is the largest of the three soil particle sizes, sand, silt and clay. Sand is 0.05 to 2 millimeters in diameter. Wet sandy soil feels gritty when rubbed between two fingers and does not maintain its shape when formed into a ball. Individual sand particles also can be seen with the naked eye. Compared to other soil textures, sand has low surface area and low charge, and hence, does not attract and retain water or nutrients. Due to this quality, sand freely drains and is typically nutrient poor. Natural sands with a variety of particle sizes are difficult to compact; however, dune and beach sands with more uniform particle sizes will pack tightly over time. Sandy soils provide good gas diffusion around plant roots, even when tightly packed.

Sand particles can be seen by the naked eye
Sand particles can be seen by the naked eye

How Can Sandy Soils Be Improved? 

The best amendment for sandy soils is organic matter. Organic matter refers to materials derived from once-living sources. Composted tree bark, wood chips, straw, or leaves, manures and green-waste are all examples of organic matter. Organic matter that is low in nitrogen, like wood, bark, and straw, needs to be composted first before it can be incorporated into the soil. High nitrogen and previously composted materials can be directly incorporated. Nurseries, garden centers, or composting companies sell many different mixtures of organic matter. Read the label or ask for a list of ingredients so you know exactly what you are purchasing. You can also make your own compost at home. Compost is used rather than raw organic matter because it usually has more nitrogen and is less likely to tie up minerals or contain toxic materials. See the USU Extension fact sheet Backyard Composting in Utah for more information on making compost. Clay is not a good amendment option for sandy soils because by mixing the wrong proportion of clay and sand, you might produce a material similar to low-grade concrete. Any time organic matter or other soil amendments are added to soils, they should be thoroughly mixed-in.

Organic matter
Organic matter is the best amendment for sandy soils

What are Managment Implications for Gardening in Sandy Soils? 

Sandy soils should be managed differently from other soil textures with higher percentages of clay. Because sand freely drains, it must be irrigated frequently to provide adequate water for plant growth. Water moves rapidly downward through sand and does not spread laterally to any great extent. Since water will not move much laterally when using drip irrigation in sand it is important to position drip emitters directly above the root zone to ensure that plants get water. The water intake rate of sandy soil is 1 to 10 inches per hour and it takes approximately half an inch of water to recharge a one-foot depth of sandy soil. Sandy soils must also be fertilized more frequently than soil with other textures since nutrients are not retained on sand surfaces around plant roots for long. Adding organic matter will improve both the water-holding and nutrient-retention capacities of sandy soils. Sandy soils may not provide adequate physical support for plants with heavy tops, like trees. Therefore trees may need to be staked for the first few growing seasons to prevent them from falling over from wind or heavy snow and ice.

Position drip emitters
Position drip emitters close to plant roots in sandy soils
Serviceberry
Utah serviceberry is very drought tolderant
and well  adapted to growing in sandy soils.

What Types of Plants Grow Well in Sandy Soils? 

Plants that prefer well-drained, and often droughty root zone conditions grow well in sandy soils. Gardeners may experience difficulties growing plants that prefer higher moisture levels because plantavailable moisture in sand is used much quicker than with finer textures, like clay. Although most tree root growth is shallow, certain species, like spruce, have very shallow roots and should not be grown in sandy soils. For a listing of trees that are tolerant of dry soils, see www.treebrowser.org (the “tolerance of drought” characteristic). For a listing of a variety of water-wise plants, see www.waterwiseplants.utah.gov (select within “soil” the conditions that best represent your soil; gardeners with sandy soils should select “does well in sandy soils”). A few examples of trees and shrubs found in Utah that will grow well in sandy soils and that are very drought tolerant are included below.

Common Name  Scientific Name
Agave, Utah*  Agave utahensis
Apache Plume*  Fallugia paradoxa
Ash, Singleleaf*  Fraxinus anomala
Boxelder or Ash-leaved or Manitoba Maple* Acer negundo
Cliffrose* Purshia mexicana
Coffeetree, Kentucky Gymnocladus dioicus
Corktree, Amur Phellodendron amurense
Cypress, Arizona Cupressus arizonica
Elm, Camperdown Ulmus glabra ‘Camperdownii’
Elm, Lacebark or Chinese Ulmus parvifolia
Elm, Siberian or Chinese Ulmus pumila
Fernbush* Chamaebatiaria millefolium
Fremont Holly* Mahonia fremontii
Ginkgo or Maidenhair Tree Ginkgo biloba
Goldenraintree Koelreuteria paniculata
Green Mormon Tea* Ephedra viridis
Hackberry, Common Celtis occidentalis
Hawthorns Crataegus species
Honeylocust Gleditsia triacanthos
Junipers Juniperus spp.
Maple, Tatarian Acer tataricum
Mountain-mahogany, Curlleaf* Cercocarpus ledifolius
Mountain-mahogany, Littleleaf* Cercocarpus intricatus
Mulberry, Red Morus rubra
Mulberry, White Morus alba
Oaks Quercus species
Oak, Gambel* Quercus gambelii
Oak, Shrub Live* Quercus turbinella
Pines Pinus spp.
Pinyon, Singleleaf* Pinus monophylla
Pistache, Chinese Pistacia chinensis
Rabbitbrush, Rubber* Chrysothammus nauseosus
Rubber Tree, Hardy Eucommia ulmoides
Sage, Big* Artemisia tridentata
Sage, Black Artemisia nova
Sage, Dorr* Artemisia dorrii
Sage, Fringed Artemisia frigida
Sage, Sand* Artemisia filifolia
Saltbush, Fourwing* Atriplex canescens
Serviceberry Amelanchier spp.
Shadscale* Atriplex confertifolia
Zelkova, Japanese Zelkova serrata

* Utah Native*

This curlleaf mountain-mahogany is very droughttolerant and well adapted to growing in sandy soils
This curlleaf mountain-mahogany is very droughttolerant
and well adapted to growing in sandy soils

Resources 

Many resources are available for people interested in learning how to garden in sandy soils:

Published June 2015
Utah State University Extension
Peer-reviewed fact sheet

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Authors

Katie Wagner, Michael Kuhns, and Grant Cardon 

Katie  Wagner

Katie Wagner

Extension Associate Professor | Horticulture | Salt Lake County

Agriculture and Natural Resources

Phone: (385) 468-4826
Office Location: Salt Lake County

Grant   Cardon

Grant Cardon

Soils Specialist

PSC Dept

Phone: (435) 797-2278
Office Location: Logan Campus | AGRS 322

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