Today’s Did You Know? isn’t so much about growing Daikon Radishes to eat as it is about growing them to improve the health of your soil. When you think of radishes, you’re probably like me and think of the little red blobs that are always left on a veggie tray virtually untouched. Or perhaps you eat them in salads. But did you know that a simple plant like a radish can improve the health of your soil?
Daikons are huge radishes, upwards of 18″ long, that grow down into your soil and mine for nutrients. As they descend their taproot into the soil, they are tapping into nutrients that aren’t available in the top few inches of topsoil. Perhaps more importantly, they are capable of penetrating all but the hardest of hardpan layers in the soil. In case you’re not sure what “hardpan” is, it’s a layer under the topsoil that inhibits moisture penetration and prevents plant roots from being able to access the soil beneath. It’s often formed from frequent tilling which is only able to fluff the top 8″-12″ of the topsoil. In suburban and urban areas, it’s often a consequence of construction and other earth moving activities. This is where the Daikon Radish is able to work its magic; the long taproot is able to break through the hardpan which allows moisture and nutrients to percolate downwards. So how does this build soil, you may be asking yourself?
Instead of harvesting the radishes to eat, you allow them to stay there and be killed by the fall frosts. What is left behind is a “carbon pathway”. I love that term…it’s such a great description for what roots can accomplish if left to their own devices. As the Daikon Radish roots decompose, they are adding organic matter to the soil as well as leaving a pathway for water and roots for the subsequent generations or other plants that you may plant the following year. And what happens to the green leafy tops? If they are left to decompose as the roots are, you have a rich mulch for the soil that is full of the nutrients that the taproot was able to mine. As the tops decompose, these nutrients are now available for the next plants that enter the system. Pretty cool how it comes full circle, huh?
If you have land that you would like to improve, consider a mass planting of Daikon Radishes. Or plant patches in your veggie garden that would otherwise go unused. Sure, they may compete with your tomatoes or cucumbers in the beginning but as they establish themselves and send their taproots deeper and deeper, they will be harvesting water from a depth far greater than your “desirable” veggies. If you are a fan of radishes, they certainly can be harvested for your dinner table…check out some ways to use them here. The seeds are available from various sources, including High Mowing Organic Seeds. I’m curious to know if any of the Mid-Atlantic Gardening readers have any experience with growing Daikon Radishes for soil building. Leave a comment below or e-mail me at firstname.lastname@example.org. Happy gardening!