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Soil Amendments
Soil Amendments
Healthy soil is the foundation of a thriving garden or landscape. Whether you’re growing flowers, vegetables, or lawn, understanding local soil conditions and health is essential. By choosing the right amendments, homeowners can improve plant growth and sustainability.
SOILS IN ALACHUA COUNTY
Alachua County’s soils are diverse but can often present unique challenges for homeowners. The most common soil types include sandy, loamy, and clay soils. Sandy soils, which dominate much of the county, drain quickly but lack nutrients. Loamy soils offer a balanced mix of sand, silt, and clay, making them ideal for plant growth. Some areas also contain clay-heavy soils, which retain water but may lead to poor root development due to compaction.
One of the best ways to determine your soil’s needs is through a soil test. The UF/IFAS Extension Soil Testing Lab offers inexpensive soil testing services to help homeowners understand pH levels and nutrient deficiencies. For a soil test with additional options, UF/IFAS has partnered with AgriTech Corp. SoilKit® to provide a more customized test. By analyzing your soil, you can make informed decisions about which amendments to use.
TYPES OF SOIL AMENDMENTS & BENEFITS
Soil amendments improve soil structure, nutrient availability, and water retention. They fall into two main categories: organic and inorganic amendments.
ORGANIC AMENDMENTS
1. Compost – A mixture of decomposed plant materials that enhances soil structure, promotes microbial activity, and improves moisture retention.
2. Organic fertilizers – Fertilizer derived from plants and animals, with the most common form being manures. Others include fish emulsions, and animal byproduct and plant meals, such as bone meal, feather meal, kelp meal, etc. Ideal manure is partially composted an/or aged to prevent “burning” of plants due to excessive salts, minimize pathogen introduction, and decrease the amount of weed seeds.
3. Cover Crops – Plants grown specifically to improve soil health and increase organic matter and nutrients. They help prevent soil erosion, suppress weeds, and can enhance soil structure. Common cover crops include legumes, grasses, and brassicas.
4. Mulch – Organic mulches, such as leaves, pine bark, pine straw, and wood chips, gradually decompose and enrich the soil with organic matter. They are also effective at conserving moisture, regulating soil temperature, and suppressing weeds.
INORGANIC AMENDMENTS
1. Lime and Sulfur – Used to adjust soil pH; lime raises pH for acidic soils, while sulfur lowers pH for alkaline soils.
2. Biochar – A carbon-rich material that can enhance soil microbial activity, improve water retention, and reduce nutrient leaching.
3. Inorganic fertilizers – Mined or synthesized from non-living materials these fertilizers contain nutrients that can be either immediately available to plants or formulated to allow nutrients to be released over a period of time. These slow- or controlled-release forms are recommended for landscapes so that plants will be able to take up the fertilizer as it is gradually released.
CHOOSING THE RIGHT AMENDMENTS FOR YOUR LANDSCAPE
Selecting the appropriate soil amendment depends on your soil type, plant selection, and landscaping goals. For example, sandy soils benefit from input of organic matter such as compost and mulch to improve soil moisture retention. Plants can also vary in their nutrient needs, depending on their species, age, and where they are planted. Young, actively growing plants with developing root systems may need amendments to give them a head start until their roots can establish and access nutrients on their own. In contrast, older plants with established root systems may not need any fertilizer at all.
BEST PRACTICES FOR SOIL AMENDMENTS
Use soil amendments, especially fertilizers, appropriately and responsibly.
Amendments should be properly incorporated into the soil ensuring even distribution.
Fertilizers should also be applied during the growing season when plants can utilize the released nutrients.
Amendments containing nitrogen and/or phosphorus can decrease water quality by running off into nearby surface waters or leaching into our groundwater, so apply only when plants need them.
Over-fertilizing can also harm plants, trigger excessive growth, and aggravate pest problems.
For more information, visit the UF/IFAS Extension Alachua County website or contact your local Extension office.
REFERENCES
Soil Survey of Alachua County, Florida. 1985. USDA, Natural Resources Conservation Service https://archive.org/details/alachuaFL1985/page/n13/mode/2up
Shober, A. and Mylavarapu, R. 2022. Soil Sampling and Testing for the Home Landscape or Vegetable Garden. https://edis.ifas.ufl.edu/publication/SS494
Toor. G. Shober, A., Reisinger, A. 2018. Soils and Fertilizers for Master Gardeners: Soil Organic Matter and Organic Amendments. https://edis.ifas.ufl.edu/publication/MG454
Bean, E., Jarrett, L., Haldeman, B., Searcy, J.K., and Jones, P. 2020. Guidance for amending urban soils with organic amendments. https://ffl.ifas.ufl.edu/media/fflifasufledu/docs/guidance_amending_urban_soils.pdf
UF/IFAS Gardening Solutions. Soil Testing. https://gardeningsolutions.ifas.ufl.edu/care/planting/soil-testing/
UF/IFAS Gardening Solutions. Organic Matter. https://gardeningsolutions.ifas.ufl.edu/care/fertilizer/organic-matter/
UF/IFAS Gardening Solutions. Fertilizer. https://gardeningsolutions.ifas.ufl.edu/care/fertilizer/
UF/IFAS Gardening Solutions. Working in your Florida Soil. https://gardeningsolutions.ifas.ufl.edu/care/planting/florida-soil/
Authored by: Dr. Cynthia Nazario-Leary, Environmental Horticulture Agent and Master Gardener Volunteer Coordinator, UF/IFAS Extension Alachua County.
Photo credits: UF/IFAS
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