Jane Tunks
San Fransisco Chronicles
Garden soil may look like just a pile of dirt, but it's actually a mini-ecosystem with organic matter such as microscopic bacteria, worms, insects and other creepy-crawly critters - all of which work together to give a plant everything it needs to thrive. Just as a mother gives life to a baby, the earth gives life to plants
At least, that's what permaculture experts Fred Bove and Kevin Bayuk told me.
And I thought it was just dirt.
Though the hardy plants in The Chronicle's rooftop garden have survived the last year on not much more than water and sunlight, a few of them look as if they might be more at home in the seedy alleys surrounding the SoMa building.
Bayuk and Bove blamed much of the plants' predicament on the poor condition of the dirt. To create a healthy garden, the soil needs to be nursed back to health. "You don't feed the tree, you feed the soil, and then the soil feeds the tree," explained Bayuk.
My gardening angels explained that it was time to get our hands dirty. We needed to thoroughly examine the soil to fully assess its quality.
I put on my brand-new gardening gloves as we made a beeline for the most pathetic plant on the roof - a spindly Meyer lemon tree with leaves the color of yellow Chartreuse. The sad-looking tree had just a couple thimble-size green fruits hanging forlornly from its branches. They were so small, in fact, that I had misidentified it as a kaffir lime tree on the illustration of the garden that we ran in the newspaper earlier this month.
"Time for a worm-juice cocktail," said Bove. He wasn't referring to his plans to unwind after a day of pulling weeds, but to a nutrient-rich concoction made from worm bin exudate diluted with water that would feed the soil. But before cocktail time, there was other work to be done. The duo wanted to excavate the tree so we could thoroughly examine its condition.
It turned out that the top foot of the planter was made up of heavily compacted soil, which was further weakened by being drained of its nutrients as a result of extensive watering and not enough fertilizing. Although water gives life to a plant - like food and oxygen - it also allows the soil's nutrients to drain to the bottom of the container.
Just then, Executive Food and Wine Editor Michael Bauer appeared on the roof and exclaimed, "That tree loses its leaves every year, and I always think it's dead but then it blooms again."
"If Michael says it's losing leaves, the plant is crying for help," commented Bove.
Though the tree was alive and blossoming, even bearing some fruit, it wasn't photosynthesizing, which was probably why the leaves had turned such a putrid color. The depleted soil was preventing the tree from getting enough nitrogen to make chlorophyll for its leaves. Bove pruned the tree, removing some of the smallest, newly sprouted branches - "the little branches are hogging nutrients" - as Bayuk explained what we would have to do to recondition the soil.
Bayuk scattered a few tablespoons of mineral-rich rock flour, or rock dust, on the soil, followed by worm "juice" blended with water, a nutrient-rich potion that is also full of bacteria, which should jump-start life in the planter.
And then he put on a thick layer of used coffee grounds from a good neighbor - Blue Bottle's Mint Plaza cafe, which is across the street from The Chronicle.
Bove jokingly referred to the three-step treatment as the "citrus tree speedball." Once the soil returns to health, it should have all the ingredients it needs to keep the tree in bloom.
To cap it off, Bove suggested we plant a nitrogen-fixing legume around the Meyer lemon tree, such as peas or fava beans, which would also give us a bigger yield out of a smaller space.
And not only that, but it would make a tasty springtime repast.
"Peas would be great in a Meyer lemon vinaigrette," declared Bove.
Finally, he was speaking in terms I could understand - lunch.
Restoring the garden starts with the soil
San Francisco Chronicle, USA
