I don’t know why but ever since I left Iowa in 1977 and tried to have a garden I’ve encountered one obstacle to success after the other. Could it be that Iowa is special and I am ignorant? Yes, and yes. It’s true that even though much of that luscious Ice Age topsoil has eroded down to the Gulf of Mexico it’s also true that there is plenty left and it makes it almost a given that you will have success gardening in Iowa. When you’ve had it easy like I did growing up and you go somewhere else where that soil isn’t like that you’re in for a big shock. I got a shock. A big ole shock!
Where I lived in Berkeley developers had graded off what little topsoil there was and all I had to work with was hardpan. At Grindstone Ranch the soil was akin to pulverized rock. Water did not percolate into it. Just ran off. In the Central Valley there was that all too familiar hardpan under the sandy clay loam. But the Central Valley soil makes Arizona soil look sumptuous.
If a person – not me – had their thinking cap on they would take one look at Arizona and think “not the garden state of the Southwest”. Except for a relatively small area in Southwest Arizona near the Colorado River. They have thousands of acres of truck farms there. Lettuce, broccoli, brussels sprouts, celery. All growing in the gorgeous effluvium of that redoubtable river. But I don’t live there, nor would I want to, because even though the climate is great in the winter it’s unbearably hot in the summer.
So, it was with great consternation that I found, having done a soil test, that my garden soil was depleted. Zip, zero, nada, bupkis, for nitrogen, potassium, potash. On top of that major alkalinity and high pH. Not good. Not good. A major boulder appears in the road.
But being the person I am, I am forging ahead just like I did in Berkeley and Madera. I should be used to this, right? And there are ways to fix it even though I’m irritated as heck that I have to. When you get lemons, you make lemonade. No matter that the lemonade will not be served this season. Maybe it might not even come until next season. But, and this is for sure, it will come!
COMPOST… in a word the solution to all soil problems. As I’ve said my long-term goal is no chemicals whatsoever, all organic and eventually no-till. Long before I get to planting I need my soil to thrive because it’s truly the only way to save the planet and make healthy plants that resist insects and disease. The documentary “Kiss the Ground” doesn’t tell you the details of how to do it, but it gives you as taste of what is possible.
So I ask myself, what is good soil? The answer is that there is no one-size-fits-all answer when it comes to soil. It depends upon the preference of the plant. If you learn how a species grows in nature, and then mimic those conditions, you will find success. A saguaro cactus grows wild in the Sonoran Desert where soils are sandy, lack organic matter, and do not hold moisture between scarce rain storms. On the other hand, a lush fern that grows wild in moist, cool forests with ample shade and rich soil would do very poorly where the saguaro cactus flourishes. Arizona native plants are adapted and designed to thrive in this soil and in the hot, arid conditions.
In my backyard I have Sonoran Desert soil, so the easiest plants to grow are those that are native to the area. This is what I’m doing – to a point. In my previous article I told about how I was going to plant things like amaranth, Navajo corn and tepary beans. They are plants that the native Americans in this area figured out how to grow.
So here are the high points for how I’m tackling my problem: (These are things my dad never had to think about when he grew his 1 acre garden behind our house in Marshalltown.)
Aeration is key: I’m making sure the soil drains well and is not saturated. I’m incorporating 50/50 existing soil and well-aged organic matter.
Then I’m going to insulate and cover the soil with mulch because this conserves water. By creating a barrier, mulch reduces evaporation from the soil and lowers water usage. It also insulates from extreme temperatures during both the winter and the summer. Did you know it can be 10 to 30 degrees cooler beneath a layer of organic mulch such as wood chips or compost? Furthermore, as organic mulch breaks down over time, it adds nutrients back into the soil.
Then I’m going to build up organic matter. Perhaps the biggest difference between desert soils and those of other parts of the U.S. is organic matter. There is a lot of rganic matter in the soils of Iowa if you don’t know. Rocks were pulverized by the momentum of the glaciers and then vegetation decomposed in the temperate climate. While most soils contain up to 10 percent organic matter, desert soils contain less than 1 percent! Yikes!
Lastly, microbes are my friend. They are the mediators of nutrient uptake and are critical to growing healthy plants and food. Pesticides, herbicides, and petroleum-based fertilizers can be detrimental to microbial life, disrupting the symbiotic relationship between soil and plants.
Wish me luck my friends. At this time I am feeling hopeful. I caught the problem before the baby plants and seeds went in the ground.