When you look at the soil in your garden, do you see healthy garden soil? Or, do you see a pile of lifeless, inert stuff? Soil is an ecosystem in its own right, with flora, fauna, and chemical reactions all its own. Healthy garden soil is full of life, and in this article, we’ll dig in! (Pun intended!)
Understanding soil is an important part of self-reliance.
What are the different soil types and compositions of those types?
Soil type classifications are in a triangular fashion between clay, silt, and loam. Clay soils hold water very well but don’t drain well, and roots have difficulty growing through it. Whereas sandy soils drain well and plant roots grow easily, it holds little in the way of nutrients. Silts have more nutrients but drain too quickly. An ideal soil is more of loam, with the three best qualities: lots of nutrients, drains well but not too fast, and plant roots can easily grow in it. As always, the usual life situation is less than ideal.
Soil composition by volume is 20-30% air, 5% organic matter, 45% minerals, and 20-30% water. Soil also contains an incredible variety of micro fauna: earthworms, beetles, and other beneficial life. Earthworms, for example, help aerate the soil and perform many chemical reactions that keep soil healthy. And let’s not forget worm castings! Those are a very rich source of many nutrients. Soil also produces antidepressant effects on exposed skin! Perhaps this is why we feel so much better after digging in the dirt. [source]
What is pH, and what are the effects of pH on nutrient uptake?
Soil pH gauges the alkalinity or acidity of soil using a scale of 1-14, with seven as the neutral mark. The closer to 0, the more acidic the substrate. The closer to 14, the more basic. Most vegetables prefer a pH in the 6.5-6.8 range. However, there are exceptions, such as blueberry, which favors a much more acidic soil.
So why does this matter? Simply put, pH has a direct effect on nutrient uptake. Within a relatively well-defined range, specifically 6-8, plants can take up most nutrients, including primary, secondary, and trace. A few micronutrients such as iron, manganese, boron, copper, and zinc drop off at 7.5. Outside of that range, the roots progressively lose the ability to absorb nutrients from the soil. Imagine you are in a full pantry and can’t eat a single thing. That would be a problem.
What are ways of testing to ensure healthy garden soil?
Soil testing is relatively straightforward, but some tests are more accurate than others. Lab testing is the most accurate and often available through your county’s Extension office. Usually, the lab will test for NPK, organic matter, and pH. They’ll also include very specific lime and fertilizer recommendations. Additional tests for various micronutrients and lead are available for an additional fee.
There are many commercial test kits available, RapiTest being one of the better known. These function by way of a chemical color reaction and typically test NPK and pH. They’re not considered highly accurate but will get you in the ballpark. Metal probes are also available, but I trust chemical color reactions more than those.
So, how do we take a soil sample?
Simple! You’ll need about 1-2 cups per sample if you’re submitting samples for lab testing. Dig down 5-7 inches in several areas of your garden, mix the soil in a bucket, and add water to make a slurry. I tend to draw a W in my beds and take a trowel full from several points along the line.
Important point: if you use a metal probe, you’ll need the slurry to get an accurate reading. Even though the instructions imply that you can stick the probe in the soil and trust the reading, you can’t. Trust me! I have done this and been there. It doesn’t work. As I said, I trust the chemical color reaction more anyway.
What is the best way to amend soil?
Compost, organic matter, mulch, fertilizers, the list of available materials is lengthy. As vegetables are grown in the soil, nutrients are used up and require replacement. In addition to the major three (NPK), a host of secondary and trace nutrients are necessary for healthy plants and yummy vegetables.
For preppers, it’s really important to stock up on soil amendments or know how to make them, because one day your life might depend on your garden.
The basic ten are:
- nitrogen
- phosphorus
- potassium
- calcium
- magnesium
- sulfur
- iron
- boron
- zinc
- copper
- manganese
- molybdenum
Deficiencies in any of these will lead to problems.
Soil pH can also be adjusted, although this takes time. Acidifiers such as sulfur and gypsum will lower pH, whereas dolomitic lime raises pH.
Nitrogen fixers: Rhizobium, Mycorrhizae
These are microorganisms that can be very useful to promote healthy garden soil. Rhizobium is a bacteria that form nodules on the roots of legumes (beans, peas, clover, and other family members). Rhizobium fixes nitrogen in the soil, helping to rejuvenate the soil in a very natural way. Nitrogen is essential to leaf formation and photosynthesis and is usually the major nutrient drained most quickly. [source]
Mycorrhiza are fungi that form a mutualistic relationship with plant roots. Mutualism is the association between organisms of two different species in which each benefits. [source]
Categories of Mycorrhiza:
- Ectomycorrhizal
- Endomycorrhiza
- Arbutoid
- Arbuscular
- Ericaceous
- Orchidaceous
- Monotropic
Different categories form relationships with different plant families.
What are the benefits of these fungi?
Benefits of these fungi include a more well-established root ball that leads to superior nutrient and water uptake, more resistance to both diseases and drought, and enhanced growth of both seedlings and root cuttings. The superior stress resistance yields the potential for less pesticide use, and some species can even remediate petroleum and heavy metals contamination. These are best inoculated into the soil when the plants are young with younger roots. Established plants can form a relationship, but it’ll take some digging in just the right spots.
For those who would like some in-depth scientific information about these organisms:
What are the effects of pesticides on soil?
Generally, pesticide overuse is bad for your soil. Living, healthy soil harbors several beneficial organisms, including earthworms, beetles, and nitrogen fixers, among many others. Many pesticides linger in the soil for years! If you must use them, use them very sparingly. These are the last resort in integrated pest management.
Soil is an incredible ecosystem in its own right, absolutely teeming with life. Healthy garden soil is essential to a productive in-ground, container, or raised bed garden system. Therefore, it pays to know everything we can about it and how to keep it healthy.
For myself, I believe that if I take good care of my assets, they’ll take good care of me! If you’re a soil nerd, be sure to check out Symphony of the Soil – it’s a brilliant documentary that will change how you look at your garden. What have you learned about soils, and how do you care for yours? Share your dirt-y stories in the comments section.
My husband really got into composting this year– we have a 40 ft x 5 ft wide x 5 ft. fall compost pile! I’ve never seen such dark, rich soil at the most seasoned end. Can’t wait to use it in our tired garden next year. He made boundaries/bumpers out of old pallets. We had some volunteer plants grow out of the compost pile–presumably from veggies we through in last year. Pumpkins, corn, gourds–it was quite the bounty!
I bought a small compost bin this year too. My city requires that compost piles be contained so I can’t just pile in somewhere on my property, so I bought a bin. I’m looking forward to seeing that lovely, rich, dark soil! Garden soil does get tired after a few years of use, and fertilizers will only go so far to revitalize them. And congratulations on the volunteers! Yum yum 🙂
???? That is one large pile!
Check into mushrooms for that pile it will help break it down even further there are mushrooms specifically for that but any mushrooms will work and their really tasty also. Lol
Thanks, Ozark! That’s a great idea. My son, who is into growing mushrooms, should have some spores we can inoculate it with.
Great article Jane!
Thank you for mentioning earthworms and fungi!
Thanks Jarhead 🙂 Got to mention the stars of the show! I always know I’m looking at healthy soil when I see earthworms. Bring on the free castings LOL
In the Ozarks it’s usually clay and rocks. Fortunately I had an area with deep topsoil that had accumulated over decades from the neighboring Dairy. The only trouble I have in my deer fenced Orchard, grape, andblueberry Vineyard, hops and thousand square foot of Garden area is usually grasshoppers and hornworm. The chickens take care of the Grasshoppers most of the time. And I prefer to grow organic and pesticide free. Every year I spread cow manure. But I also use mushrooms to break down the manure and straw. Mushrooms are more essential then most people think. Not only do they break down the soil but they help retain moisture as well. They also add nutrients. Once the mycelium has spread thoroughly throughout your garden you will find most of your veggies doing much better. I just till the mushrooms under. I also have a half buried shipping container that has a variety of Gourmet mushrooms from shiitake to lion’s mane.
Interesting! I’ve never heard of mushrooms being used in this way. Are yours supplying Mycorrhiza or are they nitrogen fixers in their own right, or something along those lines? You mentioned just plowing them under. Do you eat any of them? Especially the gourmet ‘shrooms. It almost sounds like you’re intercropping with them.
Thank you for making this a important feature topic. I am learning a little bit at a time. I’m interested in growing a small amount of food and then venturing into medicinal herbs. I will always be an apprentice only, I do not speak to be a master gardener. ????
You go girl! You’ll be a Master Gardener before you know it. FYI your county Extension office may well offer a course. Then you’ll know what a Master really is: someone who has a handle on the questions and a road to find the answers. No one worthwhile ever stops learning 🙂
Great article Jayne. The microbiome of the soil is why no till gardening is so important. I normally use a combination of lasagna gardening with raised rows/beds. I will cover with leaves in the fall and cover with a tarp to keep weed growth down. I will then add compost/peat/topsoil in the spring, plant and mulch heavily. Cover crops are another great way to improve soil health over the fall/winter. When I do containers, I always make sure to put some earthworms in each container. At seasons end, I also dump the container soil in the in ground garden.
Thank you for the kind words!
I also till very minimally, and never with a rototiller since my beds are so small. I turn the soil twice per season: once in spring and once in fall. If I didn’t the soil would be hardpan, like cement. I also add my container mix to my raised beds, but that’s not soil. MiracleGro is a combination of bark fines and coir, with some plant food added in. Next year I’m going to try mixing it with garden soil and might toss an earthworm or two in there.
The symbiosis between micro organisms and plants is amazing.
While I have a composting area many times the young weed I pull are simply dropped where they came from. In a short time they disappear back into the dirt. Weeds going to seed if I’ve been too busy are pulled and laid on the cardboard that lines my pathways. By the end of the gardening season the weeds and cardboard are just dirt pathways. They have served their purpose to keep me from sinking ankle deep after a monsoon rain.
My main focus this year was adding more to the wild edibles and medicinals here and to add fruit. I ordered 34 different seeds to naturalize. Some areas are growing and more I’ll add in spring. I have collected seed from area grown seedling fruits that are coming true with good but small fruits. Peaches, pears, and apples. I have 25 seeds to crack then stratified ( winter chill) for seedling apricots that were brought to New Mexico in the 1500s where they have been grown in the mountain villages since the earliest Spanish settlements. I also added wild blackberries, thornless blackberries, raspberries, small lingion berry bushes, a brown turkey fig, and more wild roses for the rose hips. A friend shared Jerusalem artichokes so those are reestablishing. I had them in the early 80s until 2002. I left to work for a few years and a resident here worked hard killing them off. Glad to get another start of them. Another friend shared a piece of horseradish root. It’s doing great.
My wild areas are getting more local plants added. This year I’m adding euphoria dentata. It’s our local wild poinsettia. Not red. The tips of the branches are green with some cream or white but otherwise look as you’d expect a poinsettia to look. I let it grow where it first showed up in a corn patch 3 years ago. There in enough to pull as it goes to seed and lay in a new wild “weed” and flowers bed. It will gid a nice texture there. It only grows 12-15 inches tall. The corriopsis that came up in the strawverrybed is going to seed. I’ll add that to that new bed. Usually they grow under 3 ft tall. In the strawberry bed they grew 5 feet tall. Covered in bright yellow sunny looking flowers they will be a cheerful addition.
The wild amaranth in the garden grows 5 to 6 feet tall with lots of large seed heads. Out in the yard they just grow 18 inches tall. I start early spring greens then as summer progresses and the planted greens finish up the amaranth takes off growing tall and we eat and can our fill of greens till fall. Then as the seed ripens I cut them down. The plants are composted and seed scattered for the next years harvest. I grind seed to add to flour and save seed for winter sprouts and micro greens. Same with lambs quarters. They are good microgreens.