How to build bet­ter soil? Stop treat­ing it like dirt

The Hamilton Spectator - - GO - DEB­BIE AR­RING­TON Sacra­mento Bee

The key to a great gar­den? Look un­der your feet and start valu­ing your soil.

“We treat soil like dirt, and they are not the same thing,” said noted soil sci­en­tist Steve An­drews, the “Com­post Cru­sader.”

“Dirt is the stuff that your nosy next-door neigh­bour likes to dig up on you. Dirt is the stuff in your vac­uum cleaner. Dirt gets on your clothes, the kids, the dog and the cat. But dirt is not soil.

“Soil is a liv­ing trea­sure, an amal­gam of sand, silt, clay, or­ganic mat­ter, air and wa­ter, trans­formed by time, cli­mate, to­pog­ra­phy, bi­ol­ogy, par­ent ma­te­rial — and us.”

Soil should be alive and teem­ing with mi­crobes. It’s those in­finites­i­mally small crit­ters that help plants be the best they can be.

“You can­not have healthy, pro­duc­tive plants without a healthy, liv­ing soil,” said Steven Zien, a soil ex­pert in Sacra­mento.

How many mi­crobes? Con­sider these facts from the U.S. Depart­ment of Agri­cul­ture’s Nat­u­ral Re­sources Con­ser­va­tion Ser­vice:

One cup of soil can hold more bac­te­ria than there are peo­ple on Earth.

A sin­gle spade­ful of rich gar­den soil con­tains more liv­ing species than can be found above ground in the en­tire Ama­zon rain­for­est.

If you packed all the mi­crobes from an acre of land to­gether, they would weigh as much as two cows.

“We know more about things a bil­lion light years away than about what’s hap­pen­ing six inches un­der our feet,” said Zien, founder of Liv­ing Re­sources Co. in Sacra­mento, which pro­vides soil and or­ganic gar­den­ing con­sult­ing.

Mi­crobes play a vi­tal role in soil health.

“Good, healthy soil is alive with ben­e­fi­cial soil or­gan­isms known as the soil food web,” Zien said.

“These or­gan­isms cre­ate soil struc­ture, im­prov­ing drainage and aer­a­tion. Nu­tri­ents and mois­ture are stored by the soil bi­ol­ogy that makes them avail­able to plant roots, min­i­miz­ing the need for fer­til­izer and ir­ri­ga­tion. They also pro­vide plant growth hor­mones and fight off pests, al­low­ing your plants to grow — healthy, pestre­sis­tant and drought-tol­er­ant.”

Drought can se­verely stress our soils — and mi­crobes.

Gisele Schoniger of Kel­logg Gar­den Prod­ucts in Car­son says, “They need re­plen­ish­ment more than fer­til­izer.”

The lack of wa­ter ac­tu­ally can change soil’s acid­ity (or pH) level.

“The less wa­ter, the higher the pH and the more al­ka­line your soil be­comes,” she said. “The more wa­ter, the lower the pH. Or­ganic mat­ter helps sta­bi­lize pH and keep it in the right zone, the neu­tral zone (in the mid­dle of the pH scale). If the pH is too high or too low, plants can’t use all the nu­tri­ents (avail­able in the soil) ... Or­ganic mat­ter sta­bi­lizes the pH and holds it there.”

Or­ganic mat­ter — com­post, ma­nure, shred­ded bark, rice hulls, co­conut fi­bre, peat moss, kelp, bone meal and other nat­u­ral amend­ments — does more than keep pH in bal­ance. It feeds those mi­crobes.

“Or­ganic mat­ter is the fuel that makes the whole sys­tem work,” she said. “If you do noth­ing else, put down or­ganic ma­te­rial around your gar­den.”

Or­ganic mat­ter also helps soil ab­sorb and store wa­ter. Af­ter win­ter melt, some land­scapes de­vel­oped their own is­sues. They got wa­ter­logged.

“The most im­por­tant thing to do when your soil is wet is noth­ing,” Zien said. “Walk­ing on or work­ing a wet soil causes com­paction, mak­ing it dif­fi­cult for wa­ter, fer­til­izer, air, ben­e­fi­cial soil bi­ol­ogy and roots to move through and func­tion in the soil.”

For back­yard swamps, Zien has this ad­vice:

“Wait un­til the soil dries out a lit­tle and top-dress with worm cast­ings,” he said.

“The soil bi­ol­ogy it con­tains will move into the soil with sub­se­quent rains. These crit­ters will cre­ate soil struc­ture that will open up poorly drain­ing clay soils, im­prov­ing drainage and aer­a­tion.

“In spring, when the soil dries out a bit more, aer­ate the soil. Fol­low that with an ap­pli­ca­tion of an or­ganic fer­til­izer, more earth­worm cast­ings and com­post. Avoid till­ing your soil — that ac­tu­ally causes soil com­paction.”

Those worm cast­ings have an added ben­e­fit, Schoniger said. They fight white­flies and other gar­den pests.

Sprin­kle the cast­ings in a cir­cle around the plant (at the drip line for trees or shrubs), then cover with mulch and let the cast­ings work down into the soil.

Be­sides be­ing rich in nu­tri­ents, worm cast­ings con­tain a sub­stance that nat­u­rally breaks down in­sect skele­tons, she said. But wa­ter will bead up on pure cast­ings; they need a lit­tle mulch on top to do their gar­den magic.

“Worm cast­ings are the best value you can get for your gar­den,” she said. “A white­fly won’t go near a plant that could break its body down.”

Worm cast­ings — rich in ni­tro­gen and good mi­crobes — are ad­di­tives that can make your soil bet­ter.

Chicken ma­nure — rich in ni­tro­gen — is an ad­di­tive that can make your soil bet­ter.

Sand is added to clay soils to im­prove drainage.


Phos­phate, which pro­motes flow­ers and fruit, is an ad­di­tive that makes your soil bet­ter.

Meal mix — con­tain­ing feather meal, kelp meal and al­falfa meal with mi­crobes — is an ad­di­tive that makes soil bet­ter.

Sul­phur is a soil ad­di­tive used to lower soil pH and make it more acidic.

Che­lated iron is a com­mon soil ad­di­tive that plants can take up quickly. It’s used for plants with iron de­fi­ciency.

Ver­mi­culite — made from mag­ne­sium sil­i­cates — holds wa­ter and is an ad­di­tive that can make your soil bet­ter.

Agri­cul­tural lime is a soil ad­di­tive used to in­crease a soil’s pH and make it less acid and more al­ka­line.

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