In this undated photo, large and small pores abound in this well-aggregated soil, offering roots access to both air and moisture in New Paltz, N.Y. (Lee Reich via AP)

In this undated photo, large and small pores abound in this well-aggregated soil, offering roots access to both air and moisture in New Paltz, N.Y. (Lee Reich via AP)

Let’s talk dirt: soil terms every gardener should know

Good gardens start from the ground up, but to be a good soil steward you have to understand some basic terminology.

A few important terms associated with soil:

Soil TEXTURE describes nothing more than the size ranges of the mineral particles that make up a particular soil. Those size ranges are defined in three broad classes: clay (smaller than 0.002 mm), silt (0.002 mm to 0.05 mm) and sand (greater than 0.05 mm). Rare is the garden soil that is pure sand, silt or clay, so textures usually have such names as “sandy clay” or “silty clay” to indicate the mix.

Texture is important because particle sizes reflect the sizes of the pores between them, and that influences how much air and water the soil can hold. The smallest pores actually draw water in by capillary action, then hold onto it tightly. So clay soils can stay moist through long periods without rain.

Sandy soils have large pores, too large for capillary action, so gravity easily pulls excess water down beyond the root zone. Sandy soils tend to dry out quickly. On the other hand, they are well aerated because air fills those empty pores.

The ideal soil has a little of everything — sand, silt and clay — for both good aeration and good water retention. Such a soil, with roughly equal functional contributions from clay, silt and sand is, texturally, a LOAM.

You get what you’re dealt in soil texture, but fortunately texture isn’t the end-all when it comes to water and aeration. A soil’s mineral particles can clump together — or “aggregate” — into crystal-like, larger units, which give a soil STRUCTURE.

A poorly aggregated clay soil, its small pores filled with capillary water, leaves roots gasping for air. However, when a clay soil has good structure, the small particles aggregate together to make large particles with large pores between them. At the same time, water can be held in the small pores between particles within the aggregates. A well-aggregated clay soils offers roots the best of both worlds.

While it’s usually impractical to change your soil’s texture, there are ways to manage soil so that it has good structure. (Hint: Organic matter — see below — is the key.)

FRIABILITY and TILTH, while not meaning exactly the same thing, are closely related from a plant’s point of view. A FRIABLE soil crumbles when you squeeze it gently. TILTH is the physical condition of the soil as far as plants are concerned. A soil that is friable is in good tilth. Good structure puts a soil in good tilth.

A soil that is WELL-DRAINED allows water to readily percolate through it. Drainage, as you now know, is related to both texture and structure: Sandy soils generally have little structure but, with large pores, are well-drained. Clay soils, at the other extreme, are well-drained only if they have good structure, in which case they are also in good tilth. Texture, structure and tilth aside, ground where there is a high water table cannot be well-drained; there’s nowhere for water to go.

ORGANIC MATTER is the living and once-living component of the soil. The low percentage of organic matter in soils — usually only a few percent — belies its importance. Besides its positive influence on plant nutrition and health, organic matter also provides the glues that lead to aggregation, good structure and, hence, friability, good drainage and good tilth.

CULTIVATION, in gardening, has more than one meaning. One sense is to stir the soil, as with a hoe or rototiller. Such cultivation kills weed seedlings and loosens the soil surface so that water more readily percolates in. Cultivation also refers to plant care generally, in the same way you cultivate a friendship. Caring for the soil — keeping it in good tilth — is one component of plant cultivation.

More in Life

These festive gingerbread cookies are topped with royal icing and sprinkles. (Photo by Tressa Dale/Peninsula Clarion)
Rolling out the gingerbread

With Christmas around the corner, it’s time for the holiday classic

Paper chains made of gratitude strips adorn a Christmas tree at Christ Lutheran Church in Soldotna. (Photo courtesy Meredith Harber)
Minister’s Message: Grateful and kind

What if, instead of gathering around tables and talking about what has already happened TO us, we challenge ourselves to return kindness to the world around us

Roasted broccoli Caesar salad provides some much-needed greens and fiber to balance out the rolls and gravy. (Photo by Tressa Dale/Peninsula Clarion)
A toasty, warm salad for a cozy Thanksgiving

This warm side dish provides some much-needed greens and fiber to balance out the rolls and gravy

Nick Varney
Unhinged Alaska: Some things never change. Nor should they

In the dawdling days prior to Thanksgiving, things are usually as serene as a gentle snowfall within our modest piece of nirvana

This photo from the early 1960s shows Jackson Ball enjoying the Christmas holidays with his eldest three daughters. His fourth and youngest daughter was born less than a year and a half before Ball’s death in 1968. (Photo from Ball Family memorial slideshow, 2022)
Human Complexity: The Story of Jackson Ball — Part 3

Misfortune was written across the recent history of the Arlon Elwood “Jackson” Ball family

File
Minister’s Message: Reflect upon our daily joys and blessings this Thanksgiving

There is nothing like missing something like your health to make you grateful for having good health.

Marvel Studios
On the Screen: ‘Marvels’ messy but very fun

Where the film shines is in the stellar performances of its three leads

Forever Dance performs “Snow” during “Forever Christmas 2022.” (Photo courtesy Forever Dance)
Forever Dance ushers in Christmas season with annual variety show

“Forever Christmas” will bring the sounds and movements of the season to the Kenai Central High School auditorium

These snowballs are made of chocolate cupcakes are surrounded with sugary meringue and coconut flakes. (Photo by Tressa Dale/Peninsula Clarion)
Snowballs for a snow day

Winter-themed cupcakes celebrate a day at home

File
Minister’s Message: God’s selfie

I can think of no one word that encapsulates our age, that defines our collective priorities and focus better than that innocuous little term

This is an early photo of U.S. Army soldier Arlon Elwood “Jackson” Ball in uniform. The patches, ribbons and medals on this uniform demonstrate that he had not yet served overseas or been involved in any combat. (Photo from Ball Family memorial slideshow, 2022)
Human Complexity: The Story of Jackson Ball — Part 2

Perhaps going to Alaska was the fresh start he needed at this time in his life

Virginia Walters (Courtesy photo)
Life in the Pedestrian Lane: Noise

The first 10 years we were in Alaska we lived remotely