Healthy soil equals healthy plants. Before you can know if your soil is healthy, you need to know what kind of soil you have in your garden. Soil characteristics go beyond Ph (acidity/alkalinity), though that’s important. Plants that need slightly acid soil won’t grow well in alkaline soil and vice versa. The focus is on soil types and how you can amend your soil to create loam, the best of all worlds.
Soil Types
Soil is made up of a variety of particulate material. The characteristics of your soil depend on these particles.
- Clay: High in nutrients and a hero at moisture retention, clay particles are small, fairly uniform in size and tightly packed. Clay soil drains slowly and holds very little air. Clay soils compact easily and cause a number of issues; one being stunted root systems.
- Sand: This soil type consists of large particles with a lot of space between them. It drains quickly and doesn’t retain nutrients as well as clay soil.
- Silt: Comprised of medium-sized particles, this soil retains just the right amount of water. It’s better at retaining nutrients than sand, but not as good as clay.
Most of the time, you’ll have a combination of all three soil types. Depending on your region, you may find that your soil has more clay, while another region has more sand and so on. If your neighbor has mostly clay soil, you probably have the same.
The dominant particle type determines your soil properties. The perfect soil is a 40-40-20 percent mix of sand, silt and clay. This is what is known as loam. You get the best of the three soil types from loam: moisture retention with good drainage, good airflow and decent nutrient retention.
Simple Ways to Determine Your Soil Type
There are two simple tests you can do yourself to determine your soil type.
The squeeze test
- Pick up a handful of damp – but not soaking wet! – soil.
- Rub it between your fingers.
- You have clay if the soil feels slippery and stays tightly balled.
- You have sand if the soil feels gritty and crumbles.
- You have loam if it is a little crumbly, but stays loosely balled.
The ribbon test
- Pick up a handful of damp – but not soaking wet! – soil.
- Roll it between your hands to form a ribbon.
- If it won’t form a ribbon, you have sand.
- If it forms a ribbon that breaks when you hold it up, you have around 25 – 50% clay soil.
If you don’t have loam in your garden, never fear. You can get there by adding organic amendments, or “fixes.”
Soil Improvements
Soil amendments are organic materials you add to your soil to improve it.
Improving Sandy Soil
The goal is to increase water and nutrient retention.
- Add 3 – 4 inches of organic material like finished compost or well-rotted manure.
- Add an additional 2 inches every year.
- Apply a thin layer of wood chips, bark, hay, straw or leaves. Mulching helps soil retain water and provides nutrients as it decomposes.
Improving Clay Soil
The goal is to increase water retention and aeration.
- Add 2 – 3 inches of organic material like finished compost, well-rotted manure or gypsum. Gypsum helps break up hard clay.
- Add an additional inch every year.
- Amend your soil in the fall.
- Consider permanent raised beds for better drainage. This also eliminates foot traffic, which causes compaction or soil hardening.
- Don’t spade or till any more than necessary.
Improving Silty Soil
The goal is to increase nutrient retention.
- Add at least an inch of organic amendment every year.
- Minimize compaction by limiting tilling and foot traffic.
- Consider permanent raised beds.
Types of Organic Amendments
- Compost: decomposed fruit and veggie scraps.
- Compost manure: odorless farming by-product.
- Builder’s sand: larger grains than beach sand; good for improving drainage.
- Topsoil: commercial product, partially decomposed compost with rougher texture.
- Potting soil: good for balanced water retention and drainage.
There are many other specialty mixes & “plant specific” organic soils available for the purpose of improving your soil. No matter what type of soil you start with, following these simple steps will help you get to the promised land of gardening: loam! Happy amending!
