How to transform dirt into a nutrient-rich soil plants love
People frequently ask me about the difference between dirt and soil. We use these words interchangeably, but they are not the same. When we say we are going into the garden to dig in the dirt, we are mistaken. We will dig in the soil. Only if the bed is brand-new and has not been prepped in any way will we be digging in the dirt.
Likewise, we grow plants in soil, but when we come inside, we wash the dirt off our hands and clothes. The first has a positive connotation supporting plant life while the latter is an annoyance to be washed away. Yet, they are the same thing.
According to the Soil Science Society of America, dirt is "displaced soil," which would describe the material we clean up after gardening. On a larger scale, think of the landslides we have in the canyons after a snowy winter or heavy summer rain.
Soil supports life and has history. It is layer upon layer of decaying organic matter, which provides nutrients to plants and animals. The layers are the history of that specific place over time. When it's sitting across a road, however, it becomes dirt with no history and no life. The process of soil creation and history-making needs to start again once the dirt is cleared away.
Dirt is basically dead. There are no living organisms in it to support life. It may still contain rocks, its parent material. Its lack of organic matter, structure and texture makes it susceptible to erosion. The word dirt has its origins in Middle English, when "dirt" was a word for "excrement" or "any foul or filthy substance."
The word "soil," on the other hand, has its origins in the Anglo-French word meaning "piece of ground, place," signifying something with more of a foundation and purpose.
What gives soil that foundation is the organic matter, or humus, which comprises topsoil. Good soil is a living and self-sustaining ecosystem made up of plant matter, earthworms, microorganisms, fungi, bacteria and insects.
The different sized particles of this variety of materials create structure and texture which hold the soil together, preventing erosion. The air pockets they make absorb and release water and nutrients, instead of allowing them to be leached out. Roots can travel deeply along their channels and access nutrients well below the surface. Dirt does not have these advantages.
Ironically, all soil is created from dirt over hundreds of years, but you don't have to wait that long. To transform dirt into good garden soil, you just need to add the things that distinguish the two.
Compost is the best path to healthy garden soil. It is simply raw materials that have broken down and decayed over time to create a vibrant ecosystem of organisms to feed your garden. Carbon and nitrogen, in a ration of 2:1, make suitable habitat for earthworms, insects and fungi, the elements responsible for decomposition.
You can make a compost pile inside any small enclosure, such as a ring of chicken wire or walls of old pallets. Pay attention to how much carbon and nitrogen you add. Dead leaves, garden debris, small twigs, straw, paper and cardboard provide carbon. Fresh plant material, such as kitchen scraps and grass clippings, provide nitrogen. Use the ratio of 2:1 to keep the pile from smelling like a garbage can on a hot summer day!
Place some small branches or dead flower stalks at the bottom of your enclosure and add raw materials as you have them. Water your pile and turn with a pitchfork regularly. Water and aeration speed up the process. Rotate two or three piles in varying stages of decay for a constant supply of compost.
If you don't have room for compost piles or need to discourage bears and other wildlife, compost tumblers are an excellent solution. They are available at hardware stores, nurseries and online, or are simple to make. Add the raw materials and a bit of water, turn the handle, and wait. Because tumblers tend to get turned more often, compost is usually ready sooner.
Lee Bentley and Skye Gibbins in El Salto have a tumbler to deter hungry wildlife. The tumbler has two compartments, which are in use all the time. One side has compost ready for the garden while the other has fresh kitchen waste, straw and llama manure (llama beans). As one side gets emptied out, the other is decomposing. Using a tumbler is less strenuous and more time-efficient than hand watering and aerating a pile with a pitchfork.
Another form of composting that takes even less effort is sheet mulching or lasagna gardening. It takes a little forethought because the pile should sit for a year to give it time to break down.
In an area or specific bed you want to plant next year, lay down cardboard then alternate layers of carbon and nitrogen material, like making a lasagna. The cardboard will smother the weeds or grass beneath it while making the perfect cool, damp and dark environment for earthworms. The following season, the pile should be decomposed enough to plant indirectly without having to till. Beneficial organisms will also have moved in to help create nutrient-packed compost.
Sheet mulching is also a great way to improve the soil around fruit trees and perennials while getting rid of weeds and conserving moisture.
Not everyone has space for even a small compost tumbler and buying compost may be the only way to acquire it. Large and small bags are sold at nurseries and garden centers. It may not have some of the living entities, but it has great texture that will surely improve the local soil.
Bulk compost and topsoil are also available by the yard and can sometimes be delivered. Because it has not been bagged up, it should be teeming with worms and other organisms.
I don't think we can help displacing some soil when we are done in the garden, but we can try to leave as much outside as possible.
Nan Fischer is a master gardener in Taos.
Want to know more?
Soil Science Society of America
Compost and topsoil
Petree Nursery and Greenhouses
25 Petree Lane, Taos
Rio Grande Ace South
1381 Paseo Sur, Taos
25021 Highway 64, El Prado
1384 Paseo Sur, Taos
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