Tino Carnevale:

Dirt is a gar­dener’s most im­por­tant com­mod­ity, writes TINO CARNEVALE

Sunday Tasmanian - Tassie Living - - FRONT PAGE -

All the dirt on how gar­den­ers can get the best out of their soil

Itruly love dirt and I have spent most of my life cov­ered in it in some way or an­other. It is easy to just write off soil as bor­ing back­ground and not give it the re­spect that it de­serves but it is a liv­ing, breath­ing thing and as such you can do things that help it or you can do things that harm it.

As a gar­dener your soil is your most im­por­tant com­mod­ity, it is the medium that sup­ports and sus­tains your plants. It helps to an­chor them, pro­tects roots from sun­light and tem­per­a­ture vari­a­tions but most no­tably it al­lows the plant to ac­cess the oxy­gen, wa­ter and nu­tri­ent that it holds.

Our soils are gen­er­ally made up of dif­fer­ing pro­por­tions of sand silt, clay and or­ganic ma­te­rial. This is re­ferred to as the soils’ tex­ture and how those par­ti­cles are ar­ranged is known as the soils’ struc­ture. The soil tex­ture is de­ter­mined by the par­ent rock, weath­er­ing, and past and ex­ist­ing veg­e­ta­tion. The par­ent rock is what has eroded down over time to cre­ate

In the im­mor­tal words of Young and Scott, Dirty Deeds can be done dirt cheap.

the soil and in Tas­ma­nia we have three main par­ent rock types — do­lerite, basalt and sand­stone.

Do­lerite is that rock which rises up in col­umns and makes up the moun­tains that dot our state. It forms that choco­latey coloured soil that all in all is pretty good. Basalt is that dis­tinc­tive red soil from the North-West Coast which in­spires the old say­ing that it’s so fer­tile even the power poles start sprout­ing leaves.

Then there is soil from sand­stone which if I was be­ing kind I would de­scribe as light and well drained, and if I was not, com­pletely gut­less. The best way to check your soils’ tex­ture is feel it in your hands and look at it closely, ex­am­in­ing the ag­gre­gates that make up the soil.

If you are still un­sure you can per­form a ball and rib­bon test, in fact the first time I was on tele­vi­sion I demon­strated it. It is sim­ply grab­bing a hand­ful of soil, moist­en­ing it with a small amount of wa­ter and rolling it into what can only be de­scribed as a mud poo. With that as a

na­tional TV de­but it is sur­pris­ing I am still on the show. If the soil is un­able to stick to­gether then it has a high quan­tity of sand,. If it forms a solid roll and when bent in the mid­dle doesn’t break apart then your soil is heavy clay, and if it forms but breaks when bent then luck­ily you have a loam.

Loam is the soil that plebs like me with heavy clay only dream of. It is a soil with the per­fect bal­ance of sand silt and clay so it holds on to good amounts of wa­ter and nu­tri­ents but is light and drains well. The rem­edy for the rest of us that don’t pos­sess a de­li­cious loam, is com­post. It gives a sandy soil a bit of bulk al­low­ing it to hold onto more wa­ter and in clay soils it gets in be­tween the par­ti­cles, keep­ing them apart and al­low­ing the soil to drain.

If your soil is sandy, chances are you are hav­ing to throw ei­ther lots of wa­ter at it to keep your plants happy or loads of or­ganic mat­ter, or both. Be­cause it drains so freely, any­thing added to a sandy soil will even­tu­ally leech away.

Some­thing you can try to im­prove this is to dig a trench and add a good amount of char­coal or biochar as this will ab­sorb nu­tri­ent that would oth­er­wise have leeched away, hold­ing it and mak­ing it avail­able to your plants. Mix­ing up some clay into a slurry in your wa­ter­ing can and wa­ter­ing it over your soil will help hold onto more wa­ter and nu­tri­ent.

If you’re deal­ing with a heavy clay soil, sadly adding sand has very lit­tle ef­fect un­less it is an un­rea­son­able amount. I find the sim­plest way to im­prove drainage is by trench com­post­ing. A great ad­di­tive to clay is Gyp­sum, it works to im­prove all soils but is best for break­ing clay par­ti­cles apart. The thing is for it to be ef­fec­tive long term it needs to be cou­pled with the ad­di­tion of com­posted or­ganic mat­ter to then keep them apart.

Im­prov­ing your soil does not have to be costly. In the im­mor­tal words of Young and Scott, Dirty Deeds can be done dirt cheap. Many peo­ple use the no-dig method which is very ef­fec­tive at build­ing a good soil, al­though it can be ex­pen­sive de­pend­ing on how you go about col­lect­ing ma­te­ri­als.

For me though, part of the joy of gar­den­ing is in­cor­po­rat­ing com­post into the soil with my trusty fork and driv­ing my hands into the dirt. It doesn’t mat­ter how you choose to do it, do­ing it at all is the main point.

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