Daikon as Clay Soil Amendment (and Tasty Vegetable)!

Daikon foliage, pre-deer (the stems coming out of the daikon at the bottom of the photo are actually from another annual - redwhisker clammyweed - that was growing in the same area where I scattered the daikon seeds)

In the U.S., when we think of radishes, many of us think of the cute little red skinned radishes.

I like those little reds as much as the next guy, but let me tell you something - they do not thrive on heavy clay. And by 'do not thrive', I mean that when I tried growing them, most of them failed to develop anything resembling the round, bulbous shape that the word 'radish' conjures. It was an abject disappointment.

But daikon radishes - sometimes known as tillage radish - is in a different category altogether. In fact, daikon radishes are so renowned for their ability to penetrate compacted clay soils that some people use them as a winter cover crop to aerate the soil (example Delta Farm Press). Note that if you're growing it to amend the soil, the idea is not to harvest the radish, but to allow it to winter kill and then decay in the soil.

Daikon foliage, post-deer (or possibly post-rabbit)

Having just removed some shrubs from a garden bed, I had some bare soil in September and no firm idea what I wanted to plant there yet. I thought I'd do a trial planting of daikon to see (a) if it could make a good cover crop and (b) if I could get any sizeable radishes from the bed for eating.

I happen to enjoy eating daikon radish, for instance sliced and added on top of a salad.

I sowed the seeds (from Sow True Seeds) in September, gave them a couple drinks of water to get started and then basically left them alone to fend for themselves during two months of severe drought that followed.

How did they fare?

Color me impressed. As a cover crop, daikon produced a nice head of leaves that sheltered the soil and blocked weeds. (The leaves are also edible, fyi.)

And the roots actually did manage to penetrate the hard-as-concrete parched clay soil. In fact, the soil was so tight that I had to water the plants just to pull some of the radishes without having them break in the middle.

A couple of daikon radishes pulled from the concrete, er... clay, soil

Now, it's true that my radishes did not reach the mammoth portions of ones grown in sandy-loamy soils. In Japan, where daikon radishes are quite popular, the roots can easily be 12 inches long with the diameter of a baseball bat. My daikons were only about one-third that size, but consider their growing environment and the lack of rain (which would probably have softened the soil and allowed the daikon root to expand deeper and wider), I was quite impressed and pleased with their performance.

How was the taste? I was expecting that the lack of rain would have made the radishes hot and spicy, and indeed the first daikon I ate was almost too hot to handle, but the subsequent ones I consumed generally had just enough bite.

Sliced daikon makes a lovely salad topping

I did run into two problems - deer and rabbits.

The daikon leaves seemed mainly untouched in late October, but throughout November, I saw more and more herbivore damage (and telltale deer droppings scattered around the backyard pointed to the culprits). I figured the deer shouldered all the blame, but late in November, I spotted a well-fed bunny scampering from the radish patch, so I'm dividing the blame among both types of critters.

Still, I can't blame them too much. A nearby wood has been mostly clear-cut this summer, and the drought meant that much surviving wild vegetation was parched, dead or dormant. Finding this green salad bar in my backyard probably seemed like quite a treat - maybe even a life-saving one - for the critters.

I saved some seed and hope to try again in the spring. If we have normal rainfall this winter (the last week has been promising), hopefully there will be plenty of other wild greens for the local herbivores to eat and I'll get a chance to see how the daikon fare without being denuded of their foliage. (Neither the rabbits nor the deer touched the radish root, so technically I could still dig up and eat some of the daikons, but I think I'll let them decompose over the winter to help the soil.)

Overall, I'd say this experiment was quite fun, tasty and successful. So much so, that I plan to grow a lot more daikon in the future. And for any other gardeners out there stuck with heavy compacted clay - consider giving daikon radishes a try!

A Time to Sow

So many hopes and dreams in these packets...

After months of drought, the rains have finally arrived.

With rain in the forecast, I rushed to sow the wildflower seeds - some bought, others gathered on my own property - that I had been squirreling away.

I'm taking a multifaceted approach to seed starting this year.

For those seeds that need months of cold stratification, I sowed many outdoors yesterday. After all, I figure that's how these plants propagate themselves in the wild - they drop their seeds, which undergo freezes and thaws all winter, and then they sprout in the spring.

Of course, there are drawbacks to sowing seeds outside so early in the year and letting them fend for themselves. Some seeds may get washed away. Others will probably get eaten. Still others may rot or dessicate. But with thousands of seeds sowed, presumably some will find the 'just right' conditions that allow them to germinate.

As a control, I'm holding other seeds in cold storage (the refrigerator) all winter. In February and beyond, I'll start taking action with those seeds - sowing some outdoors, transferring some into bags of wet sand (that I'll still hold in the fridge), eventually trying to start some seeds in eggshells that I'm already saving, etc.

I'll keep you all posted on the success (or not) of these various experiments.

For now, here's a list of the seeds that have been sown outdoors:

- Allium tuberosum, garlic chives (gathered from my own plant)

- Anemone virginiana, thimbleweed, native (from Missouri Wildflowers Nursery - these seeds are amazingly fluffy! I thought I'd been shipped a piece of wool when I looked into the seed packet!)

- Asclepias tuberosa, butterflyweed, native (from Sow True Seed)

- Chamaecrista fasciculata, partridge pea, native (gathered from my own plants)

- Desmanthus illinoensis, Illinois bundleflower, native (from Missouri Wildflowers Nursery)

- Echinacea simulata, glade coneflower, native (from Missouri Wildflowers Nursery)

- Gaillardia x grandiflora, blanketflower, 1/2 native (the G. pulchella parent is native across the Southern U.S., although rarely present in Tennessee) (gathered from my own plants)

- Heliopsis helianthoides, false sunflower, native (gathered from my own plants)

- Parthenium integrifolium, wild quinine, native (from Missouri Wildflowers Nursery)

- Polanisia dodecandara, redwhisker clammyweed, native (gathered from my own plant)

- Rudbeckia hirta, black-eyed Susan, native (from Sow True Seeds)

- Senna marilandica, wild senna, native (gathered from my own plant)


All of the seeds purchased from nurseries (i.e., all seeds other than those gathered from my own plants) represent my first attempts to grow these species in my garden.

Incidentally, for the first time, I tried mixing the seeds with sand before sowing. As I'd hoped, the sand helped me get better coverage and allowed me to see where seeds had already been sowed.

In colder climates, I've read that some people will wait until it snows and then scatter seeds (sample image). That way, they can easily see where the seeds have been scattered and when the snow melts, the seeds will gently sink into the ground with a ready supply of water.

I don't sow all species outside indiscriminately. Even though zinnias (Z. elegans), for example, do lightly self sow here, I suspect/hope that I'll have better germination waiting until spring to sow those seeds. And I'm also holding off on some other species I've purchased (like Monarda fistulosa, wild bergamot, from Missouri Wildflowers Nursery) where my research indicates that cold stratification does not improve germination. If the seeds will germinate just as well from a spring sowing, I'd rather scatter them then on the reasoning that fewer seeds will be lost, washed away, buried or eaten than with a winter sowing.

Dear Readers -- Do you sow any seeds outdoors in the winter? If so, do you scatter the seeds as I do or use a more controlled sowing method (e.g., something like this)?