Un­lock­ing a back­yard per­ma­cul­ture pow­er­house

The Denver Post - - LIFE & CULTURE - By Colleen Smith

Key­hole gar­dens, which orig­i­nated in Africa and now are avail­able in kits from Costco, could un­lock an ef­fi­cient, Earth-friendly new way of gar­den­ing for Coloradans.

Sim­ply put, key­hole gar­dens are cir­cu­lar or square raised beds that con­serve wa­ter, cre­ate nu­tri­ent-rich com­post and de­liver com­post tea di­rectly to plants. A “key­hole” to the cen­ter gives eas­ier ac­cess for gar­den­ers who are older or dis­abled, or want to avoid hav­ing a sore back. They also with­stand weather ex­tremes from flood to drought.

Sheila Tay­lor, a farming sys­tems co­or­di­na­tor in Uganda for the in­ter­na­tional de­vel­op­ment char­ity Send a Cow, has hands-on ex­pe­ri­ence with key­hole gar­den­ing. She’s seen these gar­dens con­tinue to pro­duce, even in African droughts and Asian mon­soons.

“These gar­dens have been around in East Africa for 15 to 20 years now for sus­tain­able ways of grow­ing veg­eta­bles,” Tay­lor said via email. “The con­cept of a wa­ter-ef­fi­cient gar­den made with lo­cally avail­able ma­te­ri­als for fam­ily veg­eta­bles could be use­ful for any­one, any­where.”

Key­hole gar­dens work on a set of prin­ci­ples, not ex­act method­ol­ogy, Tay­lor said.

The name “key­hole gar­den” de­rives from the ba­sic shape — a cir­cle with a wedge-shaped open­ing that gives ac­cess to a com­post mound at the cen­ter and sim­pli­fies wa­ter­ing and har­vest­ing.

“The spe­cific de­signs vary, which is the beauty

of these gar­dens,” Tay­lor said. “They are adapt­able.”

Jennifer Ver­prauskus, a land­scape ar­chi­tect at UpBeet Land­scapes, dis­cov­ered key­hole gar­dens in Ar­gentina and em­braced the per­ma­cul­ture prin­ci­ples — rich gar­den soil piled on top of lay­ers of com­post­ing ma­te­rial. She de­scribed key­hole gar­dens as “a glo­ri­fied nu­tri­ent dis­tri­bu­tion sys­tem.”

“It’s not rocket sci­ence,” she said. “It’s a planter with a fo­cal com­post area.”

Sarah Marcogliese, owner of Na­tive Earth Land­scape, learned about key­hole gar­dens from her mother, a devo­tee of per­ma­cul­ture.

“The whole con­cept is amaz­ing, an all-around great thing,” Marcogliese said. “I’d like to see Den­ver catch on to this trend, be­cause our next drought is right around the cor­ner. We get lulled into a false sense of hav­ing more rain­fall than we do.”

But to get started, here are some key­hole gar­den ba­sics:

To grow herbs or veg­eta­bles, sit­u­ate the key­hole gar­den in full sun.

Key­hole gar­dens ideally con­nect di­rectly with un­der­ly­ing earth, but they can be built atop a non-per­me­able sur­face, in which case they’re es­sen­tially gi­ant con­tainer gar­dens with built-in com­post­ing.

“I have a client with a side yard, un­usual space, so we’ve talked about a key­hole gar­den,” Ver­prauskus said. “But a key­hole gar­den if done right could be a fo­cal point that can fit well in any land­scape. We re­ally need to em­brace key­hole gar­dens as some­thing beau­ti­ful for our land­scape and use el­e­ments of good land­scape de­sign so it’s not thrown on the back 40. A key­hole gar­den can be a des­ti­na­tion. We can be cre­ative with how we build them so they look nice.”

Key­hole gar­dens are small for a rea­son. To keep plants within arm’s reach, the ideal size is no wider than 6 feet.

For a round gar­den con­structed at the rec­om­mended size: Place a stake in the cen­ter of a cir­cle, and us­ing a 3-foot long piece of string, mark a cir­cle as the outer bound­ary for the gar­den.

Though square key­hole gar­dens work well, too, the round shape is ef­fi­cient both for the plants and the gar­dener. “You can grow more food in a cir­cle than square,” Marcogliese said.

Form the outer walls of the gar­den to about 3-feet high by stack­ing rocks, bricks or cin­derblocks. Some key­hole gar­dens use cor­ru­gated metal or wood for the outer frame. Leave a wedge-shaped open­ing 2- to 3feet wide at the outer edge, ta­per­ing to the cen­ter.

Trap mois­ture and nu­tri­ents

To keep com­post and mois­ture in­side, line the gar­den. “You could line the whole thing with rock or stone, card­board, or you could use bam­boo to reg­u­late mois­ture and make the gar­den drought tol­er­ant,” Marcogliese said.

In the cen­ter of the gar­den, form a com­post­ing bas­ket by cre­at­ing a 1-foot di­am­e­ter cylin­der us­ing chicken wire, rab­bit fenc­ing or sim­i­lar ma­te­rial. In Africa, peo­ple of­ten use wo­ven reeds or sticks and ba­nana leaves. The com­post bas­ket ex­tends from the top of the gar­den to the ground. The gar­den gets wa­tered at the cen­ter, so nu­tri­ent-rich com­post tea leaches from the com­post bas­ket into the sur­round­ing soil.

“The bas­ket needs to let wa­ter pass through the com­post and into the sur­round­ing soil,” Tay­lor said.

“The com­post also needs to be able to prop­erly de­com­pose,” Tay­lor said. “To keep it aer­o­bic, we al­ways put some rough sticks or stones at the bot­tom to al­low air and pre­vent wa­ter­log­ging.”

You don’t want the bot­tom foot “to break down into noth­ing­ness,” Marcogliese said.

Ma­te­ri­als you al­ready have on hand can help aer­ate the base layer, she added.

“You can line the bot­tom with ash from fire­places, old cans and rocks to help drainage, saw­dust, big­ger sticks, card­board, scraps from the gar­den — any ma­te­rial that will de­com­pose,” she said. “You won’t see it, but you don’t want the bot­tom foot or so to break down into noth­ing­ness.”

Use sheet com­post­ing tech­nique to layer in brown (car­bon sources) and green (ni­tro­gen) ma­te­ri­als, adding top­soil to the up­per 12 to 15 inches. Mound soil 6- to 8-inches higher around the com­post bas­ket. Slope soil down from cen­ter to about 2 or 3 inches from the top of the outer frame.

“It’s su­per im­por­tant to ta­per the soil on an an­gle from the cen­ter com­post ring down the sides,” Marcogliese said. “Soil is heaped up like an ant hill to draw wa­ter down from top of the com­post into the root sys­tems.” Just add worms

To be­gin the com­post­ing process, add red wig­gler worms and kitchen scraps to the cen­ter bas­ket. “The big­gest prob­lem I fore­see is peo­ple not un­der­stand­ing com­post,” Ver­prauskus said. “It’s like bak­ing: the pan doesn’t mat­ter, what mat­ters is the recipe,” she said. “If you don’t follow the recipe well, it could get stinky and not be the most ap­peal­ing, but if you main­tain the com­post, it will be won­der­ful.”

“Squash is a great plant to grow in key­hole gar­dens. It will cover the soil, needs only low wa­ter and is very tough,” Ver­prauskus said. “Any­thing heat­lov­ing will work. I would avoid sen­si­tive stuff that will bolt in a full-sun en­vi­ron­ment.”

“Add a few fun flow­ers to bring in pol­li­na­tors for veg­eta­bles,” she said. “I love cal­en­dula or zin­nias.”

Plants from the um­bel fam­ily, such as car­rots and onions, and herbs such as pars­ley, dill and fen­nel, do well in key­hole gar­dens, and at­tract ben­e­fi­cial in­sects, she said.

Wa­ter the cen­ter

Use re­cy­cled gray wa­ter to ir­ri­gate the cen­ter, adding wa­ter to the com­post bas­ket. Fresh wa­ter can be used to wa­ter the sur­face when needed.

To keep com­post at the ideal con­sis­tency of a wrung-out sponge, place an eas­ily re­mov­able lid atop the com­post ring.

“We en­cour­age ro­ta­tions for both im­prov­ing soil fer­til­ity and health, and avoid­ing dis­ease and pest-trans­fer wipe­outs,” Tay­lor said. “We ad­vise that roots, leaves, fruits and legumes are ro­tated or in­ter­cropped on the gar­dens.”

“I rec­om­mend a cover crop like rye seed on the whole top layer go­ing into win­ter, and you can con­tinue to com­post,” Marcogliese said. “We have so many warm days in Den­ver that if you build some sort of hoop house, a cir­cu­lar cover, you could grown ten­der greens in win­ter.”

Photos by Kathryn Scott, The Den­ver Post

Me­gan Keefe tends her key­hole gar­den in the back­yard of her home in Lafayette. The gar­den’s clever de­sign gives gar­den­ers easy ac­cess to the veg­gies, herbs and flow­ers in­side, and the com­post at the gar­den’s core.

Keefe picks ba­nana pep­pers from one area of her key­hole gar­den. She also grows herbs and flow­ers in the gar­den.

Keefe adds food scraps to the com­post bin at the cen­ter of her key­hole gar­den.

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.