Sunday, October 9, 2011

Today I Learned (TIL)

Today I learned that if soil is "worked" (tilled, turned or amended) when the soil is too wet, it turns into a brick-like substance that can take years to rehabilitate.

This weekend, Austin finally got a good, slow, soaking rain. So far, my garden's gotten a little over an inch of much-needed moisture, and some lucky ducks in Austin have enjoyed 2 or 3 inches. And after months of heat and drought, a gardener's first inclination is to run right out after a nice rain like this and turn those beds!

But as Dr. Mark McFarland, Professor and Soil Fertility Specialist at Texas Agrilife Extension explains, soil is amazingly delicate. Working a soil that is oversaturated with water alters its very structure, turning a loose, crumbly collection of granular soil particles into a compacted mass of plate-like soil particles. The damage may not be apparent until the soil dries into a thick, hardened layer of crust which is difficult for water, air, roots and seedlings to penetrate. (Walking repeatedly on soil, wet or dry, can cause the same sort of damage.)

Pea seedling poking through soil that was turned 2 weeks ago, when dry

Once the damage is done, it's difficult to remedy and requires repeated tilling of organic matter into the hardened soil over several seasons to loosen it up again. So resist the urge and wait until the soil dries a bit before giving it a workout. With our limited rainfall and warm fall temperatures, it won't take long. You can tell when the soil is ready to work by digging up a bit of soil and forming it into a ball in your hand. If the soil ball crumbles when you squeeze it, go for it. If it's muddy or smears in your hand, wait a couple of days and test again.

For more information on soil from Texas Agrilife Extension, visit their Soils and Composting page.

(Today I Learned features a nugget of information I learned during training to become a Travis County Master Gardener.)
Words and photos © 2009-2011 Caroline Homer for "The Shovel-Ready Garden". Unauthorized reproduction is prohibited.


  1. It is hard to resist the urge to plant something when the temps get nice and cool...even if it is raining. Now I know better. Great post. I've always wanted to take the MG class.

  2. I learnt that many years ago but still had the experience just 3 years ago. My husband inadvertently turned in some compost with a spade when I was out. I had asked him to just spread the compost on the top of the soil. The bed did indeed turn to rock and it took a lot of work to repair. Lots of work with my hands breaking up those solid rock- like pieces. At least all was not lost. I can't wait for things to dry out so I can get busy with my fall garden.

  3. Yes, I learned this the hard way. When I first started planting, our clay soil was soooo hard I could only put a shovel in it when it was wet. Unfortunately, there are still areas that have that brick-like substance where it was too wet. Good reminder. I have the itch to finally go out there and work some areas that have been dry all summer!

  4. Another good lesson.
    I also learned this one the hard way. I learned to garden in the Dallas area...Blackland Prairie....that awful black clay. It's gooey when wet, and concrete when dry. Even amended, you just don't touch it when it's really wet.
    We were lucky this weekend. We got just under three inches.

  5. A-hah! That explains those dirt rocks that I inherited in one particular bed especially. When we amended the soil about a month ago, we just removed that clumping rock-dirt and scattered it in the greenbelt. Great info to know since I enjoy piddling in the garden in the rain.