The Quick & Dirty Secret to Great Gardens
“42” and Compost: The Answers to (Almost) Everything!
Sitting at the Restaurant at the End of the Universe with The Hitchhiker’s Guide to the Galaxy hero Arthur Dent, I learned that the answer to everything is “42.” In the gardening world, “42” translates to “compost.”
Arthur Dent went through a lot…just like gardeners, and sometime with just as much nonsense, so having a tried-and-true answer for everything is handy.
It’s all about the dirt!
Compost really is a wonder. Soil too sandy? Add compost. Too compacted? Add compost. Too wet? Too dry? Lacking nutrients? The solution is the same: Add compost, aka “organic fertilizer/soil amendment.”
It’s counterintuitive that so many soil challenges can have the same solution, but it’s true. Healthy soil is structurally porous, has available nutrients, and an organic content that lets the soil breath and absorb water. Soil amendments, aka compost, address each of those criteria.
Many of my gardening friends – people whose plants thrive consistently, year-after-year – confess to not using fertilizer. (I was surprised!) Instead, they add about an inch of compost each year to their gardens, layering it on top of the soil. For new beds in heavy soils, they use two to four inches.
The benefit, these Master Gardeners explained, is that compost is released slowly and won’t over-fertilize the plants. Compost’s nutritional elements are released either by weathering or by organisms in the soil, and varying according to soil temperature and moisture.
My friends could use commercial fertilizers, but here in the Pacific Northwest, fertilizers tend to quickly wash out of our soils, so frequent applications are needed. That can lead to problems with the runoff, so they use a slower, natural, longer-lasting solution instead.
Amazing Benefits of Compost
Bear with me…I’m heading into research. I promise it’s worth reading and fairly short.
A test conducted in South Dakota between 2018 and 2020 compared fields made of silty loam soil that were unamended with those that were amended with 5% compost and those with 10% compost. Here, the compost was incorporated into the soil rather than just put on top.
This is what they found after the three-year test:
· Nitrogen (N), measured in parts per million, increased from a baseline of 37 ppm, to 80 ppm for the field with 5% compost, and to 207 ppm for the field with 10% compost.
· Phosphorous (P) increased from a baseline of 10 ppm, to 56 ppm in the field treated with 5% compost, to 116 ppm for the field amended with 10% compost.
· Potassium (K) increased from a baseline of 735 ppm, to 1085 ppm for the field amended with 5% compost, and 110 ppm for the field amended with 10% compost.
· Water penetrated the unamended field at nearly 11 inches per hour. Adding 5% compost increased that rate 150%, and adding 10% compost increased it by 351%. Drainage improved dramatically.
· Average crop yields increased 39% the first year for the field treated with 5% compost, and 115% for the field amended with 10% compost. The three-year average yield increase settled at an 18% increase for the field amended with 5% compost and a 69% increase for the field amended with 10% compost.
· Total carbon in the soil increased 35% for the 5% field, and 71% for the 10% field.
These statistics, published in the Open Journal of Soil Science, are pretty amazing! As the authors noted, they “indicate sizable benefits from the incorporation of compost into soil,” that significantly enhanced soil health.
Things to Know
Adding compost is the best way to improve your garden, and it a major contributor to soil health, as the University of Maryland Extension points out. And, if you’re rather not make it, you can buy it.
With that in mind:
8.33 cubic feet of compost will cover a 100 sq. ft. garden to a depth of one inch
3 cubic yards of compost will cover a 1,000 sq. ft. garden to a depth of one inch.
One cubic ft. of compost weighs about 40 lbs.
Plant-based composts have an N-P-K (Nitrogen – Phosphorus – Potassium) analysis of approximately 1.0—0.5—1.0. Only between 5% and10% of the nitrogen is available to plants the first year it’s spread. Most of the Potassium and a small percentage of the Phosphorus are available in the first year.
Soil amendments still sound as fantastical as the oddities galactic hitchhiker Arthur Dent experienced as he traversed the galaxy. But, like him, you now know the answer to (almost) everything…at least everything related to soil. The answer is (drumroll, please): compost (aka, soil amendments)!
Wishing You Happy – and Successful – Gardening!