Soil Buying Guide

Native soil is comprised of three types of particles: clay, sand and silt.

Clay:

• High in nutrients
• High moisture retention but drains slowly
• Readily compacts because of small particles

Sand:

• Drains quickly but loses nutrients easily
• Large particles

Silt:

• Retains an ideal amount of water
• More nutrients than sand but fewer than clay
• Medium particles

Throughout the country, native soil textures are usually classified as sandy, loamy or clay, based on how much sand, silt or clay particles are present. Soil textures vary by region across the U.S.

Sandy soil:

• Often in coastal areas and the central Midwest
• Well-draining, but doesn’t hold enough water to effectively support plants

Clay soil:

• Predominantly in the Southeast
• Retains too much water that leads to root rot in growing plants

Loamy soil:

• Found in multiple regions
• Ideal for most home gardens
• 40-40-20 mix of sand, silt and clay

What kind of native soil do you have? A "feel test" can indicate the kind of soil that is most prominent in your yard.

How to determine soil texture:

• Scoop a ball of damp soil in your hand. You may need to lightly moisten it.
• Squeeze the soil with your hand.
• Sandy soils will break apart. Loamy soils will hold together and can be shaped. Clay soils will hold together and resist breaking.

The best soil for gardening is well-draining but moisture retentive. While loamy soil is ideal for most plants, it’s important to keep in mind that different plants thrive in different types of soils. For example, succulents need sandy soil, and certain trees and shrubs thrive in clay soils.

Other subsets of soil, including lime-rich chalky soil, peaty soil, and even silty and loamy soil, are not only defined by their proportion of sand, clay and silt. The acidity, or pH, of soil also helps determine the overall soil type. Knowing your soil's pH level is important because pH determines nutrient uptake.

Soil pH level:

• Before shopping for soil amendments, do a quick test of your native soil using a simple pH test kit. This will help determine if you should increase the pH with lime or reduce it with sulfur.
• A soil's pH level reflects its acidity and is measured on a scale from 0 (most acidic) to 14 (most alkaline soil).
• The ideal soil acidity for plant growth is close to neutral, between a pH of 6 and 7. Certain edibles and grasses prefer more extreme levels.

Soil is an important building block to growing strong, healthy and beautiful plants. The best soil for planting will depend on what you’re planting and where you’re planting. Different plants need different types of support from soil.

In-ground garden plantings benefit from additions of garden soil and compost mixed into your native soil. Certain plants, like blueberries and azaleas, for example, prefer acidic soil. Depending on your soil test results, you may want to amend with soil conditioner and other acidic amendments.

Container plantings need potting mix. These packaged soils are often called soilless because they do not contain soil. They’re often made from wood products. Potting mixes usually have a slow-release fertilizer and sometimes moisture-retention products incorporated. When planting, you can add a slow-release fertilizer or vermicompost to the mix. You can customize your own potting mix with a mixture of garden soil, organic compost and amendments that improve drainage and moisture retention like coco coir, peat moss or vermiculite.

Raised garden beds are just big plant containers. Because raised garden beds are usually for vegetable gardens, be sure to choose organic soils and amendments. You can buy raised garden bed soil formulated specifically for raised beds. These soils may have slow-release fertilizers. You can customize your own raised bed soil by mixing garden soil, organic compost and other amendments.

Tips for getting started:

• Determine what you'll be planting and where you’ll be planting it before you pick out the corresponding soil for planting.
• Take the time to understand the amendment and potting mix labels to ensure you've made the right choice for your plants.
• Keep your plants properly watered and feed them according to their needs and the soil’s composition.

Topsoil has different grades. Lower-grade topsoils are meant for filling and leveling holes and should only be used for those purposes. Higher-grade topsoils are great for conditioning or adding organic matter to the native soil. Although it's not an ideal planting medium by itself, topsoil can be used with other amendments like compost when planting.

Garden soil is a pre-mixed blend of organic matter and nutrients. It is designed to be mixed with your native soil to fix problems such as high or low pH, lack of nutrients and soil compaction. Garden soil is meant for in-ground use only.

Raised bed soil is used when building a raised bed on top of your native soil. Garden soil and native soil are too dense by themselves to provide adequate aeration and drainage in a raised bed. You can either combine a 50/50 mixture of potting mix and garden soil when filling a raised bed or use pre-mixed raised bed soil.

Potting mixes are formulated soil for planting in pots or containers because they allow for adequate drainage and provide space for plant roots to stretch out. Seed starting mixes are a type of potting soil engineered specifically for starting seeds.

• As the size of a container gets smaller, the importance of these benefits gets larger. Since their roots can't travel far to find the food and water they require, container plants need the extra help a potting mix can provide.
• Avoid misusing native soil and garden soil in containers. They don't provide the necessary drainage, airflow and room for roots to grow when used in containers.
• Potting mix should be amended annually.
• Most potting mixes combine peat moss, perlite and sometimes vermiculite. Most are sterilized to kill microbes that might cause plant diseases.
• Choose seed starting mix when rooting cuttings or starting seeds. This product is designed to be moisture-retentive and well-draining.

Good soil for gardening is developed to address specific planting needs. Soils can be premixed and ready to use or specially formulated for certain plants. You can also find individual amendments to add to your native, in-ground soil to improve the composition.

• Peat moss: This amendment increases the soil's ability to retain moisture and nutrients while also improving drainage. It can absorb 10 to 20 times its weight in water. Coco coir is an effective peat moss substitute, helping aerate soil in a similar manner.
• Soil compost: All manure types enrich soil and boost fertility. They help soil release nutrients to a plant continuously over long periods of time.
• Vermiculite: This common additive improves moisture retention and aeration, supporting root structure to stimulate root growth.
• Soil conditioner: This amendment helps prevent compaction in soils. It is often used to help native soil that has been damaged or to promote strong root growth. It improves drainage and aeration when added to potting soils. It can also be used as an attractive mulch around shrubs and perennials.
• Vermicompost/Worm compost: Either purchased or made in your own worm bin, earthworm castings are a powerhouse for your organic garden. Vermicompost builds healthy soil and improves pest and disease resistance in plants.
• Mushroom Compost: A byproduct of mushroom growing, this compost is a beneficial amendment that improves soil texture and moisture retention.
• Biochar: This carbon-based soil amendment is comprised of naturally occurring mycorrhizal fungi and bacteria.
• Perlite: This amendment is derived from volcanic rock that's been crushed and heat-treated into white, lightweight particles. When added to soil, it helps increase air space and improves water drainage.
• Lime: Ideal for plant growth in containers, lime increases the pH of a potting mix to around 6.0.
• Sulfur: Soil pH can be lowered with sulfur amendments that reduce excess alkalinity. Sulfur provides plants with iron for lush, green growth and enhanced water filtration.

Tips: Mix any amendments completely throughout the soil for gardening so they can work properly.
Before adding soil amendments, get a soil test performed. Most extension offices in the U.S. offer this service.

Different types of plants have different needs for their soil.

• Trees and shrubs need soil fortified with phosphorus and iron to promote root development and prevent leaf yellowing. Soil that provides continuous-release plant fertilizer will help establish strong roots.
• Lawns benefit from soils that combine composted materials, fertilizer and water control additives for the best general support.
• Flowers benefit from soils that contain organic materials such as peat moss to allow for adequate drainage. Adding compost to the soil for planting can help offset any shortages in the native soil. Lighter soils give flower roots room to grow, spread and anchor. Be sure to research the specific needs of your flower varieties.
• Fruits and vegetables belong in soil for gardening that can help manage moisture to protect your garden from over- or under-watering. Add compost and organic materials as needed to ensure your edibles get the nutrients they need for growth. Fruits and vegetables often have a greater need for water than non-edibles. Learn and follow the watering rules for each type of edible plant you have.
• Succulents need very little water. Consider soils with such additives as peat moss, sand and perlite to help with drainage and prevent soil compaction.

When you’re ready to get started, make sure you keep a few things in mind to help you have an easier planting experience.

• Determine the soil you need for your plants and planting location.
• Gather amendments to build the ideal soil for your situation.
• Understand the watering needs for your soil and plants so you can get on the proper watering schedule.
• Collect the garden tools you’ll need for soil preparation and planting. The essentials include rakes, shovels, spades, garden forks, garden hoses, garden wagons, wheelbarrows and gardening gloves.

Many packaged soils contain added nutrients to give plants a quick boost or keep them fertilized through the growing season. You will also need to fertilize your plants on a schedule that meets their individual needs.

• Nitrogen, phosphorus and potassium are some of the most common nutrients.
• When choosing your soil for gardening, look at a product's label to see how long it will keep a plant fertilized. Some soils release fertilizer for up to three months. Others are formulated with nutrients that keep a plant fed for up to nine months.
• Many plants get the most benefit from added nutrition at the start of the spring growing season.