Browse Forums Landscape & Garden Design 1 Jul 23, 2010 11:43 pm Hi All, We've just built a new limestone retaining wall to replace a decaying railway sleeper wall. In the process we've made it quite a large bed and will need some soil to back fill it. I am pretty keen on getting a dingo in to help level our back yard and get rid of our "Basikin and Robbins" lawn (31 flavours), so that we can have backfill for our garden bed and some level ground for new turf. Our lawn has lots of weeds in it also (onion weed being the most prevelant), but I am hoping that if all the current turf is put at the bottom layer, then the weeds/grass will just act as organic matter for the garden. We will look to get some organic soil and whatever else we need to nurish fruit trees for the top 300 - 500 mm of the garden bed. Am I right in saying that the top 300 - 500mm is the most important in terms of nutrient rich soil? My wife went to the Great Food Gardens workshop and was told that the feeder roots of plants can't extract much more from soil deeper than that as there is no oxygen and or light to feed the plants so they get all their nurishment from the top 300mm of soil. Anyway, below are a couple of pics of the space behind the wall and also of our crap lawn. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Retaining wall. North is to the right of the picture so we get quite a bit of shade in this bed in winter, and then full sun in summer. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Back lawn and you beaut clothes line Any recommendations on how to prep the soil and whether we can use our lawn for the first layer of fill is much appreciated. Any ideas on how many fruit trees we could get back there is also appreciated. Thanks, Chris Re: Prep for garden bed 2Jul 24, 2010 9:03 am It's going to be fantastic! and you have a very nice setup there!! Excellent job! No ideas from me, but just a word of warning IF your current lawn is kikuyu and if you use it as the bottom layer in the beds - it will shoot up and completely invade everything, no matter how deep it is burried. If it's not kikuyu, I think it should be OK, but still unsure if some weeds would be able to survive even that deep and resurface after some time in your beds You know what they say - tough as weeds ... My signature is distracting people from my wise posts ... Re: Prep for garden bed 3Jul 24, 2010 12:41 pm Bugger. One of the many varieties of lawn is kikuyu. In fact, it is the lawn is mostly kikuyu Maybe I need to feed it, and then hit it with the glyphosate to kill it all off before ripping it up. Would that help do you think? I am happy to continually maintain the garden bed and pull up any plants/grasses that we don't want in there, but, if I can do anything to help minimise the prospect of lawn appearing in the bed then that would be great. Thanks for your input. Do you think that it would provide a benefit to having it behind the wall in terms of some organic matter for the fruit trees? Would it be better to simply dump all that soil in a skip and get some clean fill in from somewhere else? Re: Prep for garden bed 4Jul 24, 2010 2:21 pm Double bugger! I hope I didn't scare you too much, but just stating my experience with kky - The Weed IMO!!! One of our neighbours has it and the stuff travels deep down under the fence and resurfaces on the sunny side (which happens to be our side). When at first I naively tried to pull it out like normal weed, I quickly learned that this Thing is coming way under the natural ground level and then just shoots up when it figures it's safe. It is so deep that I have not yet managed to dig out a whole string of roots without breaking them!!! Even used a mattock - they are still deeper!!! Now, Fu might have a totally different story ... I'll leave it for him I'm a bit confused with the fruit trees - do you mean that the bed is for new fruit trees??? I thought it's a normal garden bed (for small plants like veggies and flowers). How deep is the bed going to be? Seems like some 70cm from ground level to top of the stone wall. Maybe kky can't survive that depth, but I'd say it's pushing your luck. Maybe Google can help on its features? My signature is distracting people from my wise posts ... Re: Prep for garden bed 5Aug 06, 2010 11:42 pm Lex Now, Fu might have a totally different story ... I'll leave it for him I'm a bit confused with the fruit trees - do you mean that the bed is for new fruit trees??? I thought it's a normal garden bed (for small plants like veggies and flowers). How deep is the bed going to be? Seems like some 70cm from ground level to top of the stone wall. Maybe kky can't survive that depth, but I'd say it's pushing your luck. Maybe Google can help on its features? I just came across some of Fu's posts regarding getting rid of lawn here and here. My question(s) now are.... - is it an OK time of year to kill lawn now (in Perth) or is it too dormant? - If I follow Fu's advice of using fertaliser, Zero and Seasol to kill the lawn, could it still be used as backfill behind the wall without fear of it being absorbed by fruit trees? It will be 600 - 700mm from the soil surface and covered with some sort of organic soil mix that is suitable for fruit trees. Re: Prep for garden bed 6Aug 12, 2010 12:34 pm No expert here but I would say 1) it's better to wait for warmer weather and 2) Zero doesn't persist in soil so it won't hurt the trees, but any tiny little bit of grass that's survived the nukes will haunt you forever. Re: Prep for garden bed 7Aug 12, 2010 10:17 pm Mate nice job on the wall Anyway you pretty much answered all your own questions there http://www.bioorganics.com.au/ http://www.greenlifesoil.com.au/ http://www.gardenersdirect.com.au/ Bentonite clay as well and some zeolite mixed through. Try to incorporate your existing soil as well, especially lower down so there isn't a definable layer of poor and rich soil. Get them from a stock feed place like Mirco bros or Landmark, Elders, wesfarmers The great gardens team are spot on about the soil depth. Roots that extend further down are fulfilling a different role on the plant than nutrient or moisture absorption. Of course we can find exceptions to that rule but over all you get the idea Re: Prep for garden bed 8Aug 12, 2010 11:04 pm Thanks for all the replies. My plan now is to kill the lawn in the next few weeks (will probably wait till it warms up a little), and when we get the area levelled, we'll use that soil in the bottom of the garden bed. As Fu suggets, I'll use a mix of the suggested soil/clay/zeolite and existing soil for the rest. Thanks again for the replies. It is much appreciated. P.S. -> Thanks for the links Fu, I quite like the Fact Sheets provided on Green Life Soil. Re: Prep for garden bed 9Aug 12, 2010 11:44 pm Yeah they are good. Just another person sharing their knowledge for free with a view to a greater benefit outside their own ego There is a growing sort of underground movement like that of some seriously good info being given out Gardeners and Horticulturists are possibly the single most important group in the world that can change the way live into something more sustainable That is something uttered by some very big names in the world You are as much a part of that as anyone To kill the lawn I have posted it somewhere before (stuffed if I know where, do you ? ) Feed the butt off it. Then hit it with a glypho type product with a dash of seasol in it. Treat in the morning and make sure there is lots of healthy lush green growth. Leave it to die and then rake over some organic soil and then down goes your new EZ, Sir Walter or Palmetto turf Re: Prep for garden bed 10Aug 31, 2010 12:36 am I have a couple of final questions before we get to work on filling up this area. 1) Fu - Given we pretty much just have sand in that garden bed now, what ratio of organic soil, bentonite clay and zeolite would be required? If we can't get hold of the clay and zeolite, will the organic soil and sand mixed through be sufficient? 2) We've just sealed the back of the wall with some black tar looking stuff, and I am wondering if I need to worry about using Ag pipe and aggregate to help with drainage. This is especially true if we are looking to improve the soil to retain more moisture. Thanks, Chris Re: Prep for garden bed 11Aug 31, 2010 1:02 am well it depends on your budget really. The top 400mm needs to be at least a 50/50 mix, more if possible. As for zeolite and Bentonite clay, you will need say 3 or 4 bags of bentonite clay which would be lots and the same for the zeolite. Ideally I would mix the top layer and then have straight certified organic soils/composts but not many can afford that so work to the 50/50 but a 70 cert organic compost/30 sand is better. Drainage, it isn't going to be an issue in our sands The wall will get efflorescence on the front anyway even with the sealer behind. Re: Prep for garden bed 12Aug 31, 2010 11:58 pm Fu Manchu well it depends on your budget really. The top 400mm needs to be at least a 50/50 mix, more if possible. As for zeolite and Bentonite clay, you will need say 3 or 4 bags of bentonite clay which would be lots and the same for the zeolite. We're pretty keen to get it right, so we'll look to estimate the remaining space that requires filling behind the wall and then order that amount of organic soil. You think that 3 of 4 bags of the clay and zeolite will do for that size of bed? Do we restrict that to the top 400mm. Sorry for all the questions. Thanks again, Chris Re: Prep for garden bed 13Sep 01, 2010 12:29 am Yeah, not much need for it deeper. If you can go more bags then 10 bags will be great. http://www.gardenersdirect.com.au/comme ... BGO!%2B%2B Don't feel bad for asking questions. I love lots of questions If you get it right, you will learn some great stuff and then you will get your Fu Manchu badge and can go and teach your friends and neighbours. You'll love this new thing that will happen where things just grow and don't need lots of water or fertiliser. Don't forget the Seasol ...and molasses Re: Soil preparation for a garden bed 14Sep 01, 2010 11:56 am I might mention, the use of the many bags of those products is great. However what we are encouraging people to do when preparing soils is use Zeolite and bentonite clay in what ever amount they can. It isn't always something folks see value for money in. However those that do it will see the difference they make. Even if you can't get much organic compost in, get something in there and even if you think Zeolite and bentonite clay are luxuries, they are not. They are essentials. I do appreciate many are on very tight budgets after constructing a new home but please do not underestimate what your new landscape can do for putting pressure on tight budgets both in the foreseeable future and the distant future. There is nothing better than a soil high in organic structure in both clay and sand. It balances out pH problems naturally, it changes the way your soil behaves and most importantly it will allow plants to just grow with dependencies on much else other than the uncomposted raw mulches you put on and liquid composts. Use thick layers of straws of any sort in the early winter and aim to put harder raw mulches on top in the Spring to reduce evaporation yet continue the cycle of what a genuine mulch really does Re: Soil preparation for a garden bed 15Sep 01, 2010 12:00 pm cmooring, when the garden bed is done and everything is planted, I would for this year, use a very thick layer of straw to kickstart the microbial activity of the garden. Top up in May and then this time next year a fresh covering with the stuff you get from your local tree lopper or from http://www.mulchnet.com Plenty of Seasol, and molasses every month or two. Some Seamugus will also be a huge help in some different ways. Olsens Green Bio as well *Oh and even if they don't fit in with what you have planned, I would suggest sneaking in some Brown Boronia which is readily available at the moment here in the west It will bathe the back yard with what is argued as one of the nicest smells to man. Even if they die, for the money nothing comes close to the enjoyment they can bring for a while Re: Soil preparation for a garden bed 16Sep 02, 2010 12:25 am Thanks for all the great information. It is much appreciated. We are looking at mainly fruit trees in this area, but especially while they are young, we'll look at getting something else in there to help supplement the area. I'll post some more progress pics as we go. Thanks, Chris Re: Soil preparation for a garden bed 17Sep 02, 2010 1:03 am Kitty litter is an excellent source of bentonite clay. That is what it is Easy and very cheap! Why do we not all know this? Why do we not all do this as common knowledge? I'm working on it, tell ya friends Re: Soil preparation for a garden bed 19Sep 02, 2010 2:06 am From Wikipedia Attapulgite clays are a composite of smectite and palygorskite. Smectites are expanding lattice clays of which bentonite is a commonly known generic name for smectite clays. The palygorskite component is an acicular bristle-like crystalline form which does not swell or expand. Attapulgite forms gel structures in fresh and salt water by establishing a lattice structure of particles connected through hydrogen bonds. Attapulgite, unlike bentonite, will form gel structures in salt water and is used in special salt water drilling mud for drilling formations contaminated with salt. Palygorskite particles can be considered as charged particles with zones of + and - charges. It is the bonding of these alternating charges that allow them to form gel suspensions in salt and fresh water. Should be a reasonable substitute then I am geussing. (??) We were lucky in that our old house was so small (86 square metres) compared to the new house, they were able to take enough readings around the old backyard house before… 8 37551 DIY, Home Maintenance & Repair I'm in WA and our sandy soils make drainage a bit easier but this is what I'd be doing. Dig down to your footings and let the wall dry out. Clean it all well by brushing… 1 5251 Three options 1 Ask the liquidator 2 Find another PD customer and ask the source of their report 3 Pay for new report 3 12932 |