3 DIY Ways to Test Your Garden Soil
Updated: Jan 27
A good gardener can make it look as though growing is as easy as dropping seeds into the ground and adding water. The reality however is a bit different. A bountiful garden whether it’s flowers or food requires good soil quality. Whether you have been gardening for a while or you’re just starting out, knowing how to test repair, and manage your soil is key to your gardening success. For me, this year I’ll be starting my garden from scratch in unknown soil on our new homestead. But perhaps, you’ve been noticing a decrease in your yields year after year. Or worse, you’ve tried planting one of everything and nothing will grow. If any of these scenarios sound familiar, this post is for you! In it, I’ll go over 3 different methods to test your soil that are either free or cheap and some of them can even be done with supplies you likely already own.
What Is Soil Made Of?
To understand what you are looking at, and for, you’ll first need a basic understanding of what soil is made of. After all, soil is far more than “just dirt.” It is a complex matrix composed of, minerals (tiny rock particles), organic matter (made from the decomposition of plants and animals), living organisms (fungi, bacteria, and nematodes or earthworms), gas, and water.
For today’s article, we are focusing on the primary component of soil, the minerals which are divided into three classes, clay, silt, and sand. Each one is necessary for good soil composition, but too much of any one item can spell disaster in the garden.
Overly Silty soils can be prone to excessive compaction and erosion.
Soil that is too sandy dries out quickly, is prone to erosion, and doesn’t retain nutrients well.
Clay-heavy soils present two issues, they get waterlogged easily, then dry out and become hard as a rock.
Ideally, you want a healthy balance of these three components. The best place to start is by knowing what you’re working with in the first place. Being armed with this knowledge can help guide your planting plans, garden layouts, fertilization schedules, and amendment strategies. Few places are lucky enough to be blessed with rich, fertile soil from the outset. But for the most part, great soil is cultivated purposely over time. The most desirable soil is one that contains:
Sand provides your soil with good drainage, silt is full of essential minerals and creates air pockets, and clay helps your soil to retain water and nutrients.
Why Does Soil PH Matter?
Beyond knowing your soil composition, you will also need to know your soil pH to help you gain an understanding of what essential minerals will be available to your plants. For instance, if your soil is too acidic (under pH 7) or too alkaline (above pH 7), nutrients will have a hard time dissolving in water and reaching your plants’ root systems. Most plants thrive in slightly acidic soil (pH 5.5 to 7) so reaching a balance is essential for the health of your garden. Knowing your soil pH ahead of time will also help you to determine which soil “amendments” are right for your garden.
It’s not uncommon for novice gardeners to try to “fix” their gardening woes by applying store-bought chemical fertilizers with reckless abandon. Before trying that route it’s best to use one of the methods below to test your soil pH before you start recklessly applying fertilizers and potentially causing fertilizer burn and other problems while you’re at it.
DIY Soil Composition Test
There are plenty of fancy soil testing kits on the market some range from relatively affordable to downright pricey. But you don’t need any fancy equipment to determine your soil composition. All you need are a few simple household items.
Mason jar or similar glass jar with straight walls
Metal sieve or old colander
Baking sheet or pan
Your soil sample should represent an accurate picture of your garden, so if you have a large growing area, you may want to take a sample from a few different beds.
Once you have selected your site(s), remove any existing plant matter and roots from a 10” square area. Then scoop out approximately 6” deep from the whole cleared space. Your sample will need to be uniform and free of rocks or organic matter. To achieve this, spread your soil out on a baking sheet(s) remove any ‘extra’ items, put any worms you find back in the garden, and let what's left dry out for 24 to 36 hours.
When your soil is dry enough to crumble, run it through a sieve to ensure that your sample is a nice clean uniform mix. Then fill your jar(s) ⅓ of the way full with your cleaned and sifted dirt. Top off with water almost to the top and add in 3-4 drops of dishwashing soap. (The soap will act as a surfactant and help to keep the particles separated from one another.) Once full seal your jar and give it a good shake to completely integrate the water, soil, and soap. Then, place your jar(s) on a smooth, level surface and go live your life for 48 hours.
After your time has passed, get out your ruler and measure each layer carefully. Then use the worksheet and chart below to determine your soil composition. % SAND=(sand height)/(total height) x 100 =___________ % SAND % SILT=(silt height)/(total height) x 100 =____________ % SILT % CLAY=(clay height)/(total height) x 100 =____________ % SILT
Amending Your Soil Composition
Silty soil can be amended by adding organic matter such as compost and mulch. To do this, add an inch of compost to your beds and turn your soil before planting. When it’s time to put your garden to bed in the Fall, cover it with 2”-3” of mulch that can decompose throughout the Winter. Repeat this process each year until your soil has improved.
To amend sandy soil you will need a generous amount of compost before planting. And, once your plants are in the ground you will need to mulch around them to help retain moisture. You will also need a more rigorous watering schedule to ensure proper nutrient and moisture levels. When it’s time to put your garden to bed in the Fall, cover it with 2”-3” of mulch that can decompose throughout the Winter. Repeat this process each year until your soil has improved.
Clay soil is the opposite of sand and will take plenty of organic matter added over time to fully correct. In the Spring, add in compost, composted leaves, gypsum, and pine bark to help increase drainage over time. Just like with the other two soil types, mulch before Winter sets in. You can use the USDA Soil Diagram to help you determine your soil type:
DIY Soil pH Test 2 Ways
While you can use an inexpensive PH test kit from your local hardware store to test your soil, there are also a few DIY ways to get it done.
Vinegar & Baking Soda Test
2 Mason jars or similar glass jars with straight walls
1 Cup of cleaned soil (perhaps what’s leftover from your other tests above)
Place one cup of cleaned soil in each jar
To the first jar of soil and add 1/2 cup of vinegar. If it fizzes, you have alkaline soil, with a pH of above 7.
Add ½ cup of distilled water to the second jar and sprinkle on some baking soda. If it fizzes, you have acidic soil with a pH of below 7.
If nothing happens in either scenario, you most likely have perfectly neutral soil!
Red Cabbage Water pH Test
Distilled water (it must be distilled, tap water has its own pH)
4-6 Organic Red Cabbage Leaves, chopped
2 teaspoons of cleaned soil (perhaps what’s leftover from your other tests above)
Small Mason or similar jars
Add 2 cups of distilled water and chopped cabbage leaves to a medium saucepan. Simmer for 10 minutes then allow to cool for 30 minutes. Once cooled strain out the leaves so you are left with just the liquid. It will be a purple/blue color and have a neutral pH of 7.
Add 2 teaspoons of garden soil to a jar and top it with a few inches of cabbage water. Don’t add too much soil to your jar(s) If the cabbage juice turns a grayish-black, you have too much soil to cabbage water and you’ll need to start over. Stir or shake and wait for 20-30 minutes before checking the color with the chart below.
Amending Your Soil pH
If your soil is acidic (sour), before spring planting add sulfur, pine needles, and/or cottonseed meal then turn your beds. Be sure to do this as far in advance of planting season as you can. Three months is ideal to give your additive time to increase your soil pH. Then, repeat the process when putting your garden to bed for the winter.
If your soil is more alkaline (sweet) before spring planting add garden lime and/or wood ash before turning your beds. Again, do this as far in advance of planting season as you can. Three months is ideal to give your additive time to increase your soil pH. And, again, repeat the process when putting your garden to bed for the winter.
You’ve Tested Your Soil, Now What?
So, there you have it, three free or nearly free ways to test your soil. Additionally, your local extension office can perform detailed tests of your soil for a small fee. Simply Google “agriculture extension office [your area]” and give them a call for instructions!
Keep in mind, that there is no reason you can’t garden while you work to amend your soil. You will simply need to plant crops that are well-suited to your soil type, below are just a few examples.
Heavy Clay Soil
other crops with shallow roots
Turnips and turnip greens
What methods have you used to test your soil? Tell us all about it in the comments below, and until next time,