In the Garden with Kerry Heafner

Happy New Year! Let’s make a New Year’s resolution to concentrate on soil health in 2024. The best way to make your gardens productive and beautiful all season long is to make sure plants are in the best soil possible.  This means soil that is fertile, workable, and holds the right amount of moisture even during the swelter of an ArkLaMiss summer.  After talking to many of you over the course of last year, one of my big soap box topics for 2024 will be abandoning the work and expense of building and filling raised beds and returning to growing in native soil.  If we put our efforts into building healthy soil, we’ll see vegetables and ornamentals alike more productive than ever, and we’ll be returning carbon back to the earth where it belongs.

Successful gardening is all about emulating nature.  Think about it.  We don’t see someone going through a forest sprinkling 13-13-13 everywhere.  It isn’t necessary.  Nor do we see someone moving from tree-to-tree watering with a hose.  It isn’t necessary.  Nor do we see someone cultivating the soil in between trees.  It isn’t necessary.  For 2024, we’re going to take a few lessons from nature’s playbook, adopt and modify some practices recommended by NRCS (Natural Resources Conservation Service), and find a happy medium between no-till agriculture and standard backyard gardening techniques to get ready for the oncoming gardening season.  Best of all, we can use material this is literally in our own back yards for free!

If you still have trees that are shedding and you rake the leaves up, don’t burn them or bag them for pickup.  Use them like nature does.  Fallen leaves can be used in our gardens in several ways.  First, they are an excellent (and free) organic amendment for breaking up clay soils and making them more workable.  You’ll be surprised how quickly hard-to-work, red clay soil can be transformed into a dark, crumbly, nutrient-rich growing medium for both your edibles and ornamentals by turning fallen leaves into the soil.  Decomposition will proceed faster if you can chop the leaves up with your mowers or chipper.

Leaves are also nutrient-dense (and free). Studies conducted by researchers at Rutgers University show that leaves are a valuable source of all crop macro- and micronutrients.  As leaves decompose, nutrients tied up in their biomass are made available again to both the soil and actively growing plants.  As leaves are made almost entirely of carbon (the real definition of organic), they are extensively colonized by fungi and bacteria that will, at first, use up available nitrogen in breaking them down.  But, as decomposition proceeds and the C/N ratio decreases, nitrogen will be available again in good supply.  Remember, real soil is also a habitat for not only microbes, but for other organisms that break down organic matter like earthworms.  There is no need to add worms from the bait store to your beds.  Add leaves into the soil mix and earthworms will find you!  The day you can turn a shovel full of soil over in January and find a dozen or more earthworms is a good day!

If you don’t incorporate those leaves into the soil directly, then layer them onto your beds as a deep mulch.  Mulches will help soil retain moisture, provide habitat for soil organisms, and help regulate the soil temperature close to the surface.  An organic mulch will also start breaking down and add organic matter back to the soil.  Now, don’t forget to compost!  Leaves can also be chopped up and added to either an existing compost pile or a new pile specially made for them.  Leaves on their own break down into a material called leaf mold and you could not custom order a better organic amendment.  

Because soil is a dynamic area of biological and chemical activity, it’s best to always have something actively growing instead of letting an area just lie bare.  This gets into the practice of cover cropping.  You might know about cover crops being used on large, no till farms that practice regenerative agriculture.  But cover cropping is a beneficial technique for smaller home gardens, too.  As roots grow through the matrix of soil particles, a number of carbohydrate compounds are secreted in a gelatinous mass by cells of the root cap, the thimble-like structure that covers the root tips where cells are actively dividing.  This gelatinous mass not only allows roots to pass through the soil matrix more easily, but these compounds also feed beneficial soil microbes, the same microbes that break down organic matter we add to the soil!  In addition, growing roots help break up clay soils.  And, when the crop is terminated, nutrient-rich organic matter is added back to the soil.  So, this is win/win/win!  Cover crops promote healthy soil microbe populations, help make soil more friable, and add nutrients and organic matter back to the soil.  As I write this in early December, I have a couple sections in my garden area planted in Daikon radishes.  I sowed the seeds too thick for good radishes but growing edible roots wasn’t my goal.  Rather, my goal is to simply have something in these sections actively growing when vegetables are not growing there.  When I’m ready to terminate the Daikon crop, probably in early or mid-January, I will likely cut the leaves off and put them on the compost pile, then add a deep mulch layer on top to let the roots decompose where they are an add organic matter back to the soil.  When planting time arrives in spring, that area will be good to go.  Other commonly used cover crops include annual ryegrass and legumes like crimson clover, alfalfa, or even plain field peas.  A cover crop of legumes will give soil a double dose of nitrogen and organic matter.  Many legumes have their roots colonized by soil bacteria that convert nitrogen from the atmosphere into nitrates.  In other words, the plants make their own fertilizers.

If you’re skeptical of all this, I can personally attest to these techniques working. I started amending sandy, clay soil on my own property a year ago and have been amazed at how quickly concrete-like ground has been transformed into workable and productive garden soil.  Last season, I grew basil, cucumbers (two crops.), pole beans, watermelons, tomatoes, peppers, multiplying shallots, and okra all in two strips of ground I started amending last winter.  All heirlooms, too!  I used synthetic fertilizer only at planting and I never had to spray pesticides!  Dealing with pests and pathogens was not an issue.  Pollinating insects were abundant.  As for productivity, I grew more than enough for just myself.  In fact, I couldn’t eat eggplant and cucumbers fast enough!

So, don’t let a little clay soil intimidate you into thinking your native soil is infertile.  It isn’t.  The only problem with clay soils is they’re hard to work.  You can easily fix that with material from your own yard.  And for free!

Tune in on Tuesdays at 4:30 p.m. for In the Garden on Louisiana Living with Ashley Doughty and on Tuesday and Thursday morning at 8:45 on KWCL 96.7 FM for the radio edition of In the Garden!  Send us an email to inthegarden@agcenter.lsu.edu.