Ksk
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Re: Best Soil For Raised Bed Vegetable Garden

I have raised beds with straw bales and a little top soil spread on top. I was doubtful it would work but have found it to be a tremendous boon for select edibles & flowers. Next year I will build boxes for the bales but for now they are on the ground. You need almost no soil using this method so I just bought a gab of clean garden soil.

imafan26
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I just remembered that instead of trying to make your own mix there are two other ways to fill a bed

1. The first would be to make a lasagna bed. It would be a cheaper way to fill the bed than buying all the parts and mixing them together. Downside would be that you ideally should get it started 6 months before.
https://extension.oregonstate.edu/lane/sites/default/files/documents/lc731sheetmulchmay2015_0.pdf
2. If you have a local composting facility, they may sell a ready made mix for garden beds. If you sheet mulch part of it, you can use the garden mix for the top so you can plant right away. Or you can fill the entire bed with the nursery mix which will be ready to plant.

This is what is available to me locally. Prices are per cubic yard, if you pick it up. Delivery is very expensive ($240). Minimum is 1/2 cu. yard. This is in expensive Hawaii, you may be able to get it cheaper where you are. At $43 a cubic yard it is a lot cheaper than buying peat moss (3.8 cu ft bale = $28-$35, Compost in bags = $7 per 2 cu ft, Steer manure $5.79 per 3/4 cubic ft, Cinder $3.49 3/4 cu ft. plus fertilizer $80 for 50lbs. I have used the mix, It is good for general gardening but the cinder is not as good as sand if you are growing root crops. $37 will get a truckload of compost. However, the compost is very alkaline so, it needs to mature or have a lot of sulfur or peat moss added for acid loving plants.

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Gary350
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imafan26 wrote: 1. The first would be to make a lasagna bed.
About 35 years ago I made a lasagna bed with, new papers, cardboard, leaves, it was a disaster. I raked soil back, put down cardboard, news papers, leaves in several places then covered it with about 5" of soil it was late Oct. Spring I planted the garden everything was good until plants got tall and hot weather arrived. Cold winter weather did not allow any of the, cardboard, news paper or leaves to decompose roots were blocked from growing deep in the soil and tall plants fell over. Hot weather soil was too dry most plants died roots could not grow down deep where moisture was. I tried to till the cardboard, news paper, and leaves into smaller pieces but it wadded up in the tiller so I dug it up by hand then burned it later. I replanted the garden again in July 100 degree weather is a very bad time to plant a garden. Lasagna idea might work if I cut cardboard into small pieces, news paper wads a few inches apart, till dry leaves into soil instead of letting them lay there all winter like a wet carpet covered with soil. These days I burn cardboard & news papers they don't burn well there is a lot of black carbon that is good for the soil too. Tree leaves burned in a pile makes a lot of black carbon once flames are gone an fire looks like red hot charcoal I till it into the soil while it is still on fire & fire goes out quick. All that carbon makes the soil black but it is soon gone in another year or so. In fall before rain season starts I mow tree leaves it cuts them into tiny pieces and mower blows them onto the garden surface then I till them into the soil. The past 2 years we had to much rain tree leaves could not be mowed or raked.

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applestar
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Do you remember whether you wetted down each layer of the paper product and dry leaves? — Key to ensuring they decompose. Also helps to have healthy earthworm/wiggler and good fungi activity in soil so you can promote by adding them.

SQWIB
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I know this is an old thread but wanted to share my experiences as Gary350 has.

Not all cardboard is the same, the non corrugated recycled cardboard that is gray breaks down in a few months. Pizza boxes break down rather quick as well.

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If the cardboard remains wet it should break down quickly.

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I use real heavy cardboard for my pathways and that takes a long time to break down.

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I sometimes use cardboard to germinate my cover crop, this is the cardboard I mentioned earlier, it breaks down in a few months if it stays wet.

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For my pizza boxes, I now tear up, toss in the compost bin and pour over my slimy messy kitchen scraps and some yard waste
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I will never use shredded paper again as a mulch, it turns into an impermeable barrier.

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I used to use it as a winter cover for pots, now I either cover crop or mulch.

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I really don't use cardboard much in the garden, mainly due to the ants but do use it in my pathways and compost
My problem with cardboard is when I use it with mulch and its dry is the freaking ants.

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As far as the soil question goes (yeah I know, Old Thread, but for folks following this and not Karl because he has posted twice in 8 years, lol) I can offer a few suggestions, whatever you do use a good portion of your native soil unless it is a contaminated soil.

If doing a lasagna method, do it in the fall for the following season not the spring and keep it moist.

Cardboard is great for a base layer if building a soil on top that is deep enough for stuff like peppers and tomatoes or using at the top and punch a hole in it to plant, that is if you do not have an ant problem!

Vanisle_BC
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Just a quick comment on my experience with cardboard for pathways: Once rained on and starting to break up it can get treacherously slippery.

IrinaGrant
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Firstly thank you very much for the advice to put cardboard in a compost box. I never did it. Thanks again. How long does the cardboard decompose?

SQWIB
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IrinaGrant wrote:
Sat Apr 25, 2020 11:49 am
Firstly thank you very much for the advice to put cardboard in a compost box. I never did it. Thanks again. How long does the cardboard decompose?

Pizza boxes will break down fairly quickly, especially if torn up and saturated, the trick is to keep it from drying out.

IrinaGrant
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Thanks again for advice. I already put cardboard in a compost box, but cardboard from big boxes, not like from pizza. After I brought too much water. And now I am waiting. :-()

imafan26
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I have not used cardboard as a compost layer. I have only used it as a top layer for weed control. It has a high lignin content so depending on the thickness of the cardboard it takes a while to decompose. I don't really use it or newspaper for that matter as browns. I use them mainly for weed control. I use newspaper on the bottom of a bed after I dig it out to control weeds from coming up from below. I use several layers. Newspaper and cardboard works better as compost if it is shredded first. I put the good soil on top of the newspaper layer to plant it . On top of the good soil, I put additional layers of newspaper that I wet down and plant through that. I use the top layer as a weed barrier and mulch. For me it is the best way to control nut sedge in my garden. Eventually, the nut sedge will come back but it has been much more manageable this way. Digging out nut sedge is futile. The top layer of newspaper takes about 3 months to decompose. I tried commercial weed block but there were issues with the water not getting evenly through the fabric unless the drip irrigation is under the fabric. I still have issues with weeds sprouting around the holes in the fabric. Weeds still end up very close to the plants and are sometimes difficult to separate. Running soakers under the fabric works better if you plant in rows. I plant more intensively and usually not in rows. Weed block made of synthetic material is hard to get out of the garden when it is in pieces. I use it mainly for pathways now, but it does not stand up well to heavy traffic.

Newspaper is not the best brown to use in compost. It has a C:N ratio of about 171:1. I don't have a lot of browns. I have mostly greens. Tropical trees don't drop leaves the way temperate trees do and while I do have a few trees in my yard, only one produces branches worth composting. Palms would take years to decompose, gardenia has too many pests, plumeria and ti are not woody plants. ATTRA allows black newsprint paper in organic gardening as an allowed synthetic. ATTRA said in 2013 there was insufficient research on the toxicity of the components used in making newspaper or cardboard. Anecdotal evidence was that it was good for weed suppression and did not appear to be harmful to soil biota. As for GMO soy ink, that's a personal thing. I am not 100 percent organic, I just try to incorporate as much organics as possible. I have nothing against GMO. Considering the widespread use and that millions of people have been consuming GMO products for years. If there was any notable harm, it would have shown up by now. There are people who may be more sensitive than others to a lot of things. For some individuals, they believe the extra precautions are necessary.

As for the ants. I put out ant bait. Ants are plus minus. They harbor and nurture plants pests like aphids, mealy bugs and scale. There are some plants that attract them like gardenia and lemon grass. Tropical fire ants' bite is painful. I also have my garden patrol lizards and greenhouse frogs that eat them.

https://attra.ncat.org/can-I-use-cardbo ... anic-farm/

Nyan
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I've tried quite a few mixes for raised beds, and I have had the best success with 1/8 peat, 1/4 elCheapo Walmart soil, 1/4 compost and the rest my native soil. Then I throw a good layer of lawn trimmings over it and use a spading fork to kind of fluff it together. In the fall I'll put down a double layer of cardboard, a few handfuls of soil and either straw, wood chips or lawn trimmings on top.
Lately I've been putting a few dirty, wet, and partially broken down softwood tree limbs (the size of firewood) on the top as a way to encourage fungal breakdown. (Portobello stems and spores work too, but the darn mushrooms seem to always come up in late January or early February and get soaked by our daily rains...)
The cardboard mostly breaks down by spring to the point you can just poke a finger through it and plant. Of course we have mild wet winters so that helps a lot with decomposition.

imafan26
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I have been layering (no dig) for a couple of years. I layer newspaper (it blocks the weeds) and potting soil. The MG potting soil has more forest products in it, so I find it is much wetter and heavier. I have to add perlite to it. I have found Sta-Green potting soil. It is a little cheaper than MG. The ingredients lists peat moss, perlite, forest products, lime, and slow release fertilizer. I did trial it against MG ( the latest version) in my pots. It actually fared better than MG. Still a little heavy compared to my peatlite mix, but the plants did o.k. I put about 4 inches of the potting soil on top of the newspaper (it will break down in about 3 months) and plant in that. It keeps the weeds down. I do find that my garden needs to be tilled. It drains well, but I think forking it is not a bad idea. I have a lot of earthworms that I dig up every time I dig in it. I only have to supplement nitrogen per my soil test. I don't start side dressings until the true leaves come out.

I am reusing some of the soil in my pots, so I took out all the soil and picked out most of the roots and mixed the old soil with some of the new potting soil to put it back in the pot. I am going to leave it fallow for a few weeks to give the remaining roots time to decompose. I have learned the hard way, it is better not to plant when things in the pot are still decomposing. I'll add the starter fertilizer maybe next week. That will give me 2 weeks for the fertilizer to settle before I plant.

My results using re used soil is not so hot. I have a lot more weeds and the plants aren't as happy. It is better if I replace at least half the old mix with new.

imafan26
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The local green waste compost facility sells a nursery mix that is ready to use. However, municipal waste sometimes have stuff you really don't want in your compost like long term weed killers, perennial seeds (nutsedge is not killed by composting), and the biggest issue here is that sometimes they sell compost that has not finished cooking. You can tell if you get a truckload of it because it is usually is still steaming. When you dig into it you can see the actinomycetes are still active. You have to let the pile sit a few weeks more on site until it cools down and the actinomycetes disappear. Because the compost here is sold so young, it has a high pH. It was 8.13 the last time I was able to find their report. They have changed their website, so I can't find the reports anymore. The other thing about their nursery mix is that , they do add soil and fertilizer to it mostly manures. Although this is an island state, sand it not so easy to find. The company uses crushed cinder instead for drainage. While that works, it is not the best soil to use for root crops.

I don't use soil in my mix, because weeds are bad, but nematodes are worse. My soil is clay, so it would make for a very heavy pot.

Organics decompose and sink. Unlike rocks, or sand which can wash away, but they break down very slowly. Organics are never a one time and done thing. It has to be added constantly. The bed sinks and if you stop adding organics your soil web suffers as well because if you harvest out the plants and nutrients from the soil, you have to put something back in its' place.

Java
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Lots of people have mentioned to use native soil. Whenever I dig up my lawn a little bit, first thing that grows is Weeds. I have a location that is ignored and it is weed fest, dig a little the soil is actually awesome there. Would love to use it.

How do u avoid weeds?

pepperhead212
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Try solarizing - this isn't a fast process, and not as fast now, as when it gets warmer out, plus the sun is higher in the sky then, but the heat and steam will eventually kill most of the weeds and their seeds, as well as a lot of pathogens. Simply wet the soil well, then cover the area completely with heavy plastic - clear actually works best, because it allows the heat to penetrate into the soil. In 4-6 weeks you should see all those things that were growing under there dead. They start out like crazy, since it's like growing in a greenhouse, at first, but they fizzle out, eventually.

One guy I know would turn the soil over again, and re-cover it, to get the last few seeds that were down deep.

imafan26
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Digging up the soil will make it easier for weeds seeds to germinate from below or those that blow in. In stead of digging up the soil, cover it. Solarizing is one method. Instead of digging the soil, layer it. You can put cardboard over the grass instead of digging it up (as long as you don't have long term chemicals in them). Add your compost and soil mix on top to plant in.

It is cheaper to get bulk products, but if you don't know where it comes from, it may not be all that great a bargain. A lot of "topsoil" is fill that was dumped from somewhere else and is mostly sub soil. Real topsoil is the top few inches in a forest. There is not that much of that available. Before you plant you should have the soil tested because it may be lacking nutrients. Organic matter should be about 5%. Planting in pure compost does not work out. Unfinished compost will steal nutrients from the plants. If you have time, it is better to prep the bed up to 6 months in advance so it has time to settle, especially if you are wanting to do an organic garden.

https://learn.eartheasy.com/articles/3- ... ised-beds/

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Gary350
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Chickweed is very bad in TN I covered my 32" x 34' onion bed with cardboard last fall to kill chickweed. Wind blew cardboard away so I put the cardboard back then covered it with mulch so wind can not blow cardboard away. Cardboard was in the onion bed 4 months when I went to remove the cardboard March 1st the cardboard was almost gone it was mostly rotted away. Cardboard should work good to cover grass and kill it.

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hendi_alex
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I use a mix of inexpensive Stay Green potting soil from Lowes, combined with perlite bought in bulk, and compost. I start a bed with about four inches of soil and gradually fill it over a 2-3 year period. We grow lots of potted plants, and at the end of the season that material goes into the raised beds. If you want a lighter, soilless mixture, blend a bag of more expensive Miracle Grow potting soil with two bags of Stay Green, plus the perlite and compost.

imafan26
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I liked the sta green potting soil. The plants grew well. My biggest complaint with it was that mushrooms were growing in the containers and it was a little heavier than I like so I added additional perlite for drainage.

Miracle grow changed how they make their potting soil, It has more compost in it now. For me, with all the rain I get and the way I water, it does not work well, because things stay too wet for too long. I can use it as part of my soil mix recipe replacing part of the peat moss and mixed with perlite. Using the 3 part formula replacing the compost with the MG potting soil, and mixed with an equal part of peat moss, but I double the perlite, because, I need a mix that dries faster, otherwise it will turn green.

If you have good topsoil, there is not reason not to use it as part of your mix. Equal parts good topsoil, a good blended compost, and drainage material ( coarse sand, rice hulls, cocao husks, coarse sand, perlite ( if the soil is not clay , otherwise you get cement).

To save money on a deep bed you can do hugulkulture and put some partially decomposed logs in the bottom of the bed or do core gardening using decomposed straw (not hay) bales. These would save space and money since you can plant most things in a shallower layer of your prepared mix. Over time the carbon in the logs and straw will break down. Core gardening is a technique that can also require less watering.

https://morningchores.com/core-gardening/

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hendi_alex
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Adding lava rocks and old wine corks, or any kind of pebbles can help keep the soil from getting water logged. Shredded coconut hulls are probably great but are way too expensive here. Perlite is my go to material for lightening the soil.

imafan26
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I have used cinder. It definitely works, especially for citrus trees. It is not the best material for root crops. I think one of the many problems I have with root crops besides having too much nitrogen is that my base soil is clay. It retains a lot of water and is very heavy and most roots crops would rather have a sandy loam.

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Gary350
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imafan26 wrote:
Thu Jun 01, 2023 9:15 pm
I have used cinder. It definitely works, especially for citrus trees. It is not the best material for root crops. I think one of the many problems I have with root crops besides having too much nitrogen is that my base soil is clay. It retains a lot of water and is very heavy and most roots crops would rather have a sandy loam.
I had an old junk BBQ grill full of lava rocks, I dumped the lava rocks in the garden. Lave rock must have turned to sand I have never seen any of those rocks since the day I dumped them 2 years ago.

imafan26
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For those of you who do strictly organic. When you start a brand new garden, what do you put it in it and how long does it take for the soil web to build up? Do you do anything to increase the soil microbia. EM1, biochar, bokashi, etc.

What do you do if you have nitrogen deficiencies in young plants? What kind of organic nitrogen is readily available in a new bed that does not have an established soil ecosystem yet.



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