Last November I saw a creeping bentgrass nursery in Japan. The nursery had been fumigated to kill seeds in the soil before the bentgrass seeds were planted.

image of daikon seedling with bentgrass

I was surprised to see, scattered across the nursery, plants with big leaves that clearly were not creeping bentgrass.

“What’s that?” I asked, wondering how such plants could be growing if the soil had been fumigated.

“It’s a daikon,” the greenkeeper told me. That’s a big radish, Raphanus sativus var. longipinnatus.

“These daikon seeds germinate in just a few days,” he told me. “We use them to check that the soil is safe for planting the bentgrass, after fumigation.”

A few radish seeds are planted in the fumigated soil. Once the radishes germinate, then the bentgrass an be planted with full assurance of safety.

image of daikon used to check for safety of germination after fumigation

I hadn’t seen that before. That’s a cool turfhack and no need to worry about those radishes infesting the bentgrass nursery as a weed. The radishes won’t tolerate low mowing, so once the bentgrass is mown, no more daikon.