6 Easy Soil Tests You Can Do with a Jar

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Today we’re not talking about fancy gadgets, high-tech lab tests, or anything that requires a subscription. We’re talking jars. Jars, dirt, and the low-key sorcery that happens when you shake them up and squint at the results.

This article is for the curious gardener who suspects their soil is hiding secrets. Is it clay? Is it sand? Is it plotting against your tomatoes? You’ll find out. All six of these soil tests can be done with household items and a bit of patience (emphasis on the patience, especially for the overnight ones).

We’ll look at texture, drainage, compaction, even the number of worms — which, yes, is a thing. A surprisingly important thing. You might think of it as garden forensics. We’re not just planting. We’re snooping.

Let’s start with a basic but wildly underrated test. All you need is a clear jar, a handful of soil, and a little faith in gravity.

1. The Soil Texture Test (a.k.a. The Shake-and-Pray Method)

Let’s say you’ve inherited a garden bed. Or maybe you just ripped up a chunk of lawn in a moment of ambition. Either way, you’re staring at a patch of dirt wondering if it’s going to be a leafy paradise or a plant graveyard.

Time to meet the Soil Texture Test. It’s like carbon dating for your dirt — minus the carbon, science degree, or tragic documentary voiceover.

What you need:

• 1 clear jar (mason jar, spaghetti sauce jar, old pickle jar — no one’s judging)
• Enough soil to fill 1/3 of the jar
• Water
• 1 squirt of dish soap (the unscented kind, unless you want your garden smelling like fake lemons)

How to do it:

1. Fill the jar 1/3 of the way with soil from your garden. Remove any sticks, rocks, or worms politely.
2. Top it up with water, leaving about an inch of space at the top.
3. Add a drop or two of dish soap. This breaks the surface tension so the particles actually separate instead of clumping together in a sullen mud blob.
4. Screw the lid on tight. Very tight. Shake the living daylights out of it. Do this for at least 2 minutes.
5. Place the jar somewhere it won’t be disturbed and let it sit for at least 24 hours.

What You Will See Happen

The soil will settle into layers. Sand falls first, then silt, then clay. Organic matter may float at the top like a confused garnish.

What It Tells You

The ratio of sand, silt, and clay determines how your soil behaves. Sandy soils drain fast but don’t hold nutrients. Clay soils cling to water and choke roots. Silt is somewhere in between. You want a mix. Loam, if you are lucky. But at least now you know what you’re working with.

This test won’t give you exact percentages unless you go full nerd and break out a ruler. But even the eyeball version is better than guessing. Soil lies. This test doesn’t.

2. The Drainage Test (a.k.a. The Puddle of Truth)

Some soil holds water like a jealous ex. Other soil lets water pass through like it’s late for a train. You want something in the middle. Something with boundaries, but also a sense of hospitality.

This test helps you figure out how your soil handles water. Which, in turn, tells you how likely your plants are to drown, dry out, or live happily ever after.

What you need:

• A shovel or trowel
• Water
• Something to time 30 minutes (phone, watch, kitchen timer, sundial if you’re fancy)

How to do it:

1. Dig a hole about 12 inches deep and 6 inches wide. Try not to feel too much like a dog in the process.
2. Fill the hole with water. Let it drain completely. This preps the soil and keeps it honest.
3. Fill it again and start timing.
4. Check how much water drains in 30 minutes. Then check again at the 1-hour mark.

What You Will See Happen

If the water vanishes like magic, you’ve got sandy soil. If it sits there staring back at you for an hour, you’ve got clay. Somewhere in between means you’re in business.

What It Tells You

Good soil drains about 1 to 2 inches per hour. Fast drainage means water and nutrients don’t stick around long enough for your plants to use them. Slow drainage can lead to root rot, fungal parties, and other wet disasters. Knowing how your soil behaves with water is the first step to picking the right plants or tweaking the soil you’ve got.

This is also a great excuse to stand around outside and tell anyone who asks that you’re “running a test.” Sounds scientific. Looks like digging a hole. Perfect.

3. The Earthworm Test (a.k.a. The Squirm Report)

Earthworms are the unofficial soil inspectors of your garden. They’re quiet, low-maintenance, and constantly working overtime to make your dirt better. If you’ve got worms, you’ve got life. If you don’t… well, your soil might be the botanical version of a ghost town.

This is the easiest test of the bunch, unless you have a fear of squiggly things. In which case, consider gloves and emotional support.

What you need:

• A small shovel or trowel
• A 12-inch by 12-inch area of moist (but not soggy) soil

How to do it:

1. Dig a hole about 6 inches deep in your chosen patch of soil.
2. Place the soil on a tarp, board, or just next to the hole.
3. Sift through the soil gently and count the earthworms. Be kind. They’re on your side.

What You Will See Happen

You might find one or two worms just chillin’. You might find a wriggly party. Or you might find nothing and start wondering about your life choices.

What It Tells You

If you find at least 5 worms in that sample, your soil is in pretty good shape. Fewer than 3 might mean your soil is lacking organic matter, is too acidic, or too dry. Worms are picky roommates. If they don’t like the conditions, they pack up and leave.

This test is less about precision and more about vibes. Earthworm vibes. If they’re happy, your garden will probably be happy too.

4. The Compaction Test (a.k.a. The Push-and-Grunt Method)

If your soil feels like concrete when you try to dig, your plants are going to struggle like they’re trying to grow in a parking lot. Compacted soil blocks water, air, and roots — basically all the things plants actually need to live.

This test tells you whether your soil needs some serious loosening up. Or if it’s already the spa day your roots have been dreaming of.

What you need:

• A wire flag, a straightened coat hanger, or a long screwdriver
• Moist soil (not dry, not waterlogged)

How to do it:

1. Take your tool of choice and push it straight into the soil.
2. Note how far it goes before you meet resistance and start muttering under your breath.
3. Try this in a few spots around your garden to see if it’s a widespread issue or just one grumpy patch.

What You Will See Happen

If your tool slides in like it’s butter on a warm day, your soil is loose and friable. If it only goes in an inch or two before you need to start body-weighting it, you’ve got compaction problems.

What It Tells You

Compacted soil limits root growth, blocks oxygen, and turns every rainstorm into a pond party. Plants hate it. If your soil is compacted, it’s time to break out the garden fork, add compost, or consider planting cover crops. Your future carrots will thank you.

This test is quick, low-tech, and kind of fun if you enjoy poking things with sticks. Which, let’s be honest, most of us do.

5. The pH Test (a.k.a. The Sour or Sweet Situation)

Soil pH isn’t just a science-y thing for lab coats and microscopes. It determines what nutrients are available to your plants and which ones might be locked up tighter than a bank vault. Too acidic? Too alkaline? Time to find out if your soil’s personality leans sour or sweet.

Most garden plants like things slightly acidic to neutral. Somewhere between 6.0 and 7.0. Outside that range, you’ll start getting sad tomatoes and confused hydrangeas.

What you need:

• pH test kit or pH meter (cheap ones work just fine for a backyard check)
• Distilled water (regular tap water can mess with your results)
• A soil sample or two from different garden areas

How to do it:

1. Take a small soil sample from about 4 to 6 inches below the surface. Remove rocks, roots, and drama.
2. Mix it with distilled water according to your test kit’s instructions.
3. Use the test strip or probe to check the pH. Wait the recommended time before reading.

What You Will See Happen

The strip or meter will show a number. Lower numbers mean more acidic soil. Higher numbers mean more alkaline. Somewhere around 6.5 is the sweet spot for most vegetables, herbs, and flowers.

What It Tells You

Soil that’s too acidic (below 6) can block calcium, magnesium, and phosphorus. Soil that’s too alkaline (above 7.5) can lock out iron and other nutrients. If your pH is way off, plants might look sick even if everything else seems fine. You can amend with lime or sulfur depending on the direction you need to go, but first you need to know where you are.

Think of this as a mood ring for your garden. Once you know how your soil feels, you can actually do something about it.

6. The Root Observation Test (a.k.a. The Plant Autopsy)

If you’ve got a plant that looks like it’s on the brink of giving up on life, don’t just blame the weather or your watering schedule. The roots hold the answers. Literally. This test gets your hands dirty, but it tells you a lot about what’s going on underground.

Think of it as CSI: Garden Edition. Except instead of DNA evidence, you’re looking at roots. And instead of crime, it’s probably overwatering. Or poor drainage. Or possibly user error. Who can say?

What you need:

• A struggling plant (in-ground or in a pot)
• A trowel or small shovel
• The willpower to unearth what you might have done to this poor thing

How to do it:

1. Carefully dig up the plant, trying to keep as much of the root ball intact as possible.
2. Shake off excess soil or gently rinse it under water to expose the roots.
3. Inspect the roots closely for color, structure, and smell.

What You Will See Happen

Healthy roots are white or light tan, firm, and smell like fresh soil. Unhealthy roots are dark, mushy, smelly, or stringy. Think overcooked noodles that have been left in the sink too long. That’s not what you want.

What It Tells You

Blackened or rotting roots usually mean root rot, often caused by too much water or poor drainage. Roots that are tightly circling inside a pot signal the plant is root-bound and needs more space. Sparse or stunted roots might point to compaction or nutrient issues. Whatever you see, you’re learning something useful. The plant may not recover, but its sacrifice will not be in vain.

This test isn’t pretty. But it’s real. And if you’re brave enough to face your mistakes with a trowel in hand, your future plants will benefit from what this one taught you.

Final Soil Thoughts (No, Not That Kind)

You don’t need a lab coat or a degree in dirtology to understand your soil. Just a few jars, some patience, and a willingness to poke around in the ground like a curious raccoon.

These six tests won’t make you a professional soil scientist. But they will make you a smarter gardener. You’ll waste less time guessing, spend less money on stuff you don’t need, and—most importantly—your plants will stop silently judging you.

Good soil isn’t magic. It’s a result of knowing what you’re working with and making adjustments. So run a test or two, take some notes, and maybe even name a worm while you’re at it.

Your garden knows what it needs. These tests just help you listen.