9 Soil Tests That Will Determine How Healthy Your Garden is

Interested in planting a garden or improving your current lot? To create a cornucopia of lush plants, flowers, and foods, your soil needs to be healthy and fertile.

Before you throw your gardener’s hat on and start to feed or dig into that dirt, it’s a good idea to test out its quality. Knowing what areas need some nurturing will get you on the right path before planting.

One of the most important components of soil health is the pH level, which tells you about the alkalinity or acidity of your soil. Armed with that information, you’ll be able to determine which plants are compatible with your soil.

Besides pH, there a number of other things you need to look for so that your plants are being nourished properly. The guidelines below come from the Williamette Valley Soil Quality Card and were developed by a group of farmers from the region in Oregon.

Although many of you probably don’t live in the state of Oregon, these soil-testing tips can still be applied to your own garden. Read on!

  1. Structure and Tilth

    Check the graininess of your soil to make sure it allows for free movement of air, water, organisms, and nutrients. Do this when it’s not too dry or wet. Dig down into the dirt about 6-10 inches and scoop out a section that’s the size of a soup can. Squeeze the soil with the your fingers, noting how much pressure is needed to crush the “crumbs”.

    Now, wet some of that same soil with a couple squirts of water and do the squeeze test again. Ideally, you want the grains to retain their shape whether wet or not. No breaks is excellent. If there’s a little breakage, you have moderately good soil, but if it completely crumbles, it’s not what you want.

  2. Compaction

    Compacted layers of soil will restrict plant growth by inhibiting the movement of air, water, and food. Check for compaction by sticking a wire flag into different parts of the soil bed, paying attention to when it bends or stops. You want at least of foot of penetration so that roots can grow freely.

  3. Workability

    You want to see if the soil breaks up evenly to allow for water flow and easy movement. It also lets you know how to avoid compaction. Run a tiller through the soil multiple times to assess how much energy you have to exert – that’s workability.

    What you want is minimal to low-medium amount of energy and soil should be easy to till. If it requires too much to till, your seedbed is probably not a good candidate for what you want to plant.

  4. Organisms

    The little critters that live in the dirt help it to flourish. Whether microscopic or not, you want most of them there. Dig in at least 1/2 foot into the soil. Scan the soil for 2-4 minutes, looking for insects and other tiny creatures.

    If you have a magnifying glass or fancy microscope, all the better. A great variety is at least 4 kinds of organisms in multiples, but you can get away with two different kinds for your needs. Anything less gets a 0 rating.

  5. Earthworms

    This one is simple: do you have earthworms? They help to break down plant material while also nourishing the soil. At least three present in a shovelful of dirt is okay, while five or more present is awesome.

  6. Plant Vitality/Vigor

    What’s already growing out of the ground and is it healthy? Look at color, pest infiltration, or signs of diseases on the plants (including weeds!) growing out of your soil section. Are they stunted? Are they even? If they look healthy, you’re ready for your next crop. If not, you’ll need to nurture that soil a bit.

  7. Root Growth

    Roots that are getting enough moisture, nutrients, air, and organism love will thrive and that’s a sign of great soil. Grab a trowel and dig around the base of the plant, examining the depth of its roots, color, and root structure. Fine roots that extend into the dirt are what you’re looking for, as dry, mushy, or a handful of roots indicate poor soil or compaction issues.

  8. Water Penetration

    Is your soil porous enough for water to flow through it freely? Observe your soil after it rains to see if water pools on top of it or if it gets absorbed easily. Too much runoff or water sitting on top of the dirt can indicate poor infiltration.

    If there’s no pooling after 24 hours, it’s ideal. If it takes up to 3 days for the water pooling to disappear, you have moderately good soil. Anything beyond that shows your soil probably will not funnel water properly.

  9. Water Availability

    Good soil structure will allow for water to be held in its pores making it available to plants in between irrigation sessions or rains. You’ll have to test this one by actively checking plant growth following their exposure to water.

    Do they do well in between watering sessions? Does water evaporate too quickly? An indication of good soil is when your plants are getting enough to hold them over until the next rain or watering. The exception would be extremely hot weather conditions.

Rich soil will ensure that your plants are getting everything they need, and with the aid of these tests, you can make sure your setup is the healthiest for your garden.

Have you ever done soil tests on your garden? What adjustments did you need to make? Are these tests helpful?