Perfect for those in the southern hemisphere, like Australia where it’s now spring, keep this test in the back of your mind when your conditions in the U.S. improve. Today in Chicago, it’s wet and turning cold, not the best conditions for this test. I may or may not do the test this fall, but will do it first thing in the spring. For those who can do it now, here are the instructions.
Every year in the spring I do a mason jar soil test to see the soil structure in my garden. It helps me decide if I need to make any amendments to the soil. This is a simple and easy test to take if you are creating a new garden area, you’ve recently moved, or you want to do a cool experiment with your kids.
Knowing the structure of your soil will help you determine how much water and fertilizer your plants will need, and what soil amendments to make. Your soil is a mass of mineral particles, water, air, and dead organic matter. The size and form of those particles make up the basic soil structure.
An understanding of your soil is perhaps the most important aspect of gardening and will give you the best success.
There are three soil components – Clay, Sand, and Silt
Clay is the smallest mineral component. These tiny flat particles fit closely together to create the greatest surface area of all soil types. Clay soil contains needed nutrients and also stores water well. So well in fact, that drainage is slow in clay soil. It is also the slowest to warm in the spring.
Sand makes up the largest particles in soil structure. These are rounded, rather than flat and allows for larger space between the particles. Water drains quickly from the soil that has a lot of sand and the nutrients drain faster too. If your soil is mostly sand the plants will need more water and fertilizer.
Silt represents the middle size pieces. It is made up of rock and mineral particles that are larger than clay but smaller than sand. Individual silt particles are so small that they are difficult to see. To be classified as silt, a particle must be less than .005 centimeters (.002 inches) across.
The combination of these three particles is called loam and is considered the ideal garden soil. Knowing how close (or far) you are from loam will help you decided what amendments to make this spring planting season.
The Mason Jar Soil Test
- Use a clear, clean, empty jar with a tight lid. A pint or quart Mason jar works fabulously.
- Fill the jar about half full of garden soil. You can use soil from different areas of the garden to get an overall view or make a test for each garden bed.
- Fill the jar nearly to the top with water. Leave room for shaking.
- Tighten the lid and shake the jar for several minutes so that all the particles are in suspension.
- Set your mason jar soil test aside for several hours, so the particles have a chance to settle. They will separate into clay, silt, and sand layers.
Read the Results of your Mason Jar Soil Test
- The bottom layer will be the heavier particles, sand, and rocks.
- The next layer will be the silt particles.
- Above that are the clay particles.
- Organic matter may be floating on the surface of the water.
- The color of the soil gives a clue to its character – light colors usually have less organic content than dark soil and dark soil warms faster in the spring.
If your jar test is 20% clay, 40% Silt, 40% sand = Loam, you have the perfect combination. You’ve been working hard in your garden!
30% clay, 60% silt, 10% sand = Silty Clay Loam
15% clay, 20% silt, 65% sand = Sandy Loam
15% clay, 65% silt, 20% sand = Silty Loam
These other types of soil will require some amending with organic materials.
Common amendments include:
• Yard trimmings compost – Sometimes sold as “garden compost,” yard trimmings compost is the most widely available material suitable for high-rate incorporation into soil. Private composting companies usually produce it.
• Leaves from deciduous trees – Leaves are perhaps the best and most readily available organic matter source for vegetable gardens or other areas that get some annual tillage. Ask your friends to save their leaf bags for you. Don’t let them go to waste in a landfill!
• Crop residues – Fresh or composted crop residues may be available from nearby farms, tree-trimming companies, or even your own kitchen. Uncomposted crop residues may contain weed seeds, while properly composted residues are weed-free. Make your own kitchen compost bin.
• Animal manures and manure composts – Many manures and manure composts have high soluble nitrogen, ammonia, or salt content, or high pH (above 8)In general, it is best to avoid manure and manure composts for high-rate applications to planting beds. Use manures in small amounts to replace nitrogen–phosphorus–potassium fertilizers.
What Gardening Problems Are Caused by Poor Soil Quality?
Many problems with home vegetable gardens, fruit trees, shrubs, and flower gardens are caused not by pests, diseases, or a lack of nutrients, but by poor soil physical conditions.
Symptoms of poor soil quality include the following.
- The soil is dried and cracked in summer.
- Digging holes in the soil is difficult, whether it is wet or dry.
- Rhododendrons, hydrangeas, and other shrubs wilt in hot weather, even with added water.
- Leaves on shrubs turn yellow and have brown, dead sections on them, particularly on the south side of the plant.
- Tomatoes and peppers get blossom-end rot, even if fertilized with calcium.
- Water tends to pool on the soil surface and to drain slowly, or it runs off the surface.
Download this handy publication, Improving Garden Soils with Organic Matter to learn more ways to improve your soil and happy gardening!