Soil for raised garden bed ?

Discussion in 'Growing Marijuana Outdoors' started by Triple6Greens, Feb 15, 2016.

  1. So my plan is to make a raised garden bed for my plants for when I move them outside.






    I mapped out to build a 4X15 foot raised garden bed. In this new hobby of mine I figured I start growing veggies too. But they are not my main concern.. the cannibas is.






    My plan is to get some 2X12 boards and build a square and throw some soil in it. The bed will be built on top of plain dirt outback.






    My question is what soil should I put in it? I don't plan on putting new soil in every grow.. that be to expensive but each grow I can add nutes to the soil to liven it up.


    Was thinking of a good soil from the store and I just add some perlite to it. I need a soil that is gonna last and be a good medium for year around use outside.






    So what would be a good base soil to fill the planter with?
    I will be needing 60cu ft so I don't wanna be spending a ton of money but willing to spend a little more for better quality
     
  2. I would check around your local landscape supply yards and see if they have any decent quality compost for vegetable gardening. You may find ads on craigslist for local compost/manure too. Depending on what you find, you may be able to grow right in the compost, or mix it with some sphagnum peat and aeration to make a suitable growing medium.

    In between seasons, just topdress the bed with a simple organic fertilizer and keep it mulched. You could also experiment with N-fixing cover crops for a free source of plant nutrition.

    These two threads are good places to get ideas about soil mixes and how to grow with minimal inputs.

    https://forum.grasscity.com/organic-growing/1116550-easy-organic-soil-mix-beginners.html

    https://forum.grasscity.com/organic-growing/1299862-no-till-gardening.html/page-620
     
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  3. Are you growing organically?
     
  4. #5 CurryLeafTreeHugger, Mar 21, 2016
    Last edited: Mar 21, 2016
    It might be best if you sat down and read some general purpose gardening books. Try Square Foot Gardening by Mel Bartholomew (I might have spelled that wrong) and Ruth Stout's book, which has 2 titles:

    The Ruth Stout No-Work Garden Book
    Gardening Without Work


    Or just read this article - it will hit the highlights. I'd still suggest digging up a copy up of the whole manifesto, but that'll give you an idea.

    I've been gardening for over 50 years. It's a different mindset, different procedures, from growing indoors.

    Firstly, if you build your bed properly, you will not need to "add nutes". The worms will come because you are using deep mulch (read Ruth). They will pull that deep mulch down into the ground, as well as eating up the roots, leaves, and etc. They will aerate your soil, support helpful microorganisms, create fertility, and support good tilth. This will also support increased availability of oxygen in the root zone, as well as improving soil drainage and structure. So you'll be down to just fertilizing the plant appropriately, which is more directed and focused than "adding nutes". Your general soil fertility and structure will take care of itself if you give it the right starting conditions.

    As I recall - its been over 40 years since I read the book - Ruth was a big fan of straw or hay as mulch. This is fine if you have access to such for free or low cost, and I did, for many years. But if you don't have access to helpful agricultural byproducts, make our consumer society work for you. I have for the past quarter century used plain brown cardboard from broken down boxes (like moving boxes, or the shipping boxes from Amazon) with cheap organic bark mulch on top as my mulch.

    As the cardboard rots and disappears courtesy of our wormy friends, at the beginning of the season you can just pull back the bark mulch and lay down new cardboard.

    You can get chopped up lawn waste and tree limbs from most municipalities for somewhere between free and cheap. If they have composted lawn clippings, use those as your mulch/soil. Make sure it is composted - not piles of grass. Grass will mat and cause water to run off rather than soak in. Always compost before use.

    Ground fir, pine, or hardwood bark can also be used as mulch. The size is not that important when used as mulch; when used as soil amendment/mix - go for around an inch and smaller. I might say 0.5" at other times, that's because that's the size I shoot for for potting mixes. But some larger pieces are ok for outdoor raised beds, just don't go hog wild and dump a bag of pine nuggets that are 2" and 3" and try to use that for soil mix, LOL!

    I would still use cardboard as weedblock with any mulch.

    If you buy bagged wood mulch (fir if possible), make sure it is NOT DYED and does not contain chopped up pallets and old houses and decks. Do not use cedar; the use of redwood may or may not be ok, there isn't a lot of agreement on that. Fir is best, pine is good, hardwood is ok. The size of the mulch matters, it should be smallish but not composted with a lot of small fine particles. This is less important in a raised beds as worms will solve a lot of the issues, but your first crop or two will appreciate a little extra initial care until the worm populations really get up and running.

    Don't use sawdust, or at least use it at your own risk. It can cake and cause water to run off, tends to blow around like the dust that it almost is, and has, on rare occasions, spontaneously combusted in people's gardens. Best to avoid. Compost it instead. Don't use black walnut or black locust sawdust at all.

    To build your bed, unless your soil is indeed very poor or very poorly drained, I would let it build up over time rather than trying to fill a 60 sq ft bed 10" deep with new soil. If you keep adding mulch and compost every year, it will build up faster than you think.

    First pin down clear plastic mulch over the area you want to use for growing. (you can do this with plain brown cardboard, no cereal boxes or glossy type cardboard or magazines, but you have to prepare the bed the previous fall for the coming spring if you use cardboard). This will kill the grass AND help to kill the roots and weed seeds. Should take a couple of weeks depending on your climate and the time of year. This works best when its sunny and hot.

    You should be able to take a square bladed spade and cut the dead grass out if it hasn't composted well enough. It'll at least be easier than trying to pull it up alive and green.

    DO NOT try to just till live grass under. Grass spreads by rhizomes - stemmy looking things that travel under ground.

    Grass rhizomes think tiller blades were created specifically to help them procreate. The tiller blades chop up the rhizomes and make lots and lots MORE of them. It's sort of like trying to kill starfish by cutting them up and throwing them back in the water. Next thing you know, you have a bazillion new starfish growing from each piece. Or, in this case, a bazillion new grass blades just ready and willing to sprout. Pull it up and discard it.

    Build your raised bed sides. I have always used treated lumber. Plain pine dimensional lumber won't usually last more than a few years - again depending on your climate. Drive posts at the corners and nail your 2x12s to the posts. You'll also need a post in the middle - 2x12's normally come in 8' lengths and up (even lenghts, like 8', 10', etc). You could probably find a 16' long board (or rather 2 of them) but then you have to transport it. 2 8' lengths will be cheaper than one 16' board, but mostly they'll just be a lot easier to handle.

    About treated lumber - the new stuff doesn't leach. It's safe for growing edibles. The old stuff actually didn't leach MUCH. The problem with the old stuff was due to sawdust not being handled properly, or kids chewing on it. But the new stuff is even less likely to leach or cause problems. Even using it for your corner (and center support) posts would greatly decrease the amount of time and effort you have to put in to future bed repairs.

    Using posts to attach your side boards to helps to reduce problems with frost heave or ground subsidence as time passes. It also makes it super easy to level the whole thing. Your ground isn't level. If you build a box and try to lay it on the ground, it will twist and eventually pop apart. Just a pain. Easier to level on the posts and then fill in around it as needed (and inside it).

    If you have gopher/mole problems, now is the time to line the bottom of the bed with 1/4" galvanized hardware cloth. This won't last forever either, but it'll last a good long time, and it'll keep critters away from the plants. Staple it to the sides of the raised bed so it sort of makes a "Bottom" to the bed. Personally I pull it under the sides (and ends) and staple it to the face. This way they can't muscle in between the inside surface and the wire (had you stapled it to the INSIDE surface of the boards) and pop the wire loose. You can toss some dirt along the sides to cover that up if you are concerned about getting scratched or snagging on it in the future.

    You can use either a construction-grade staple gun or get the kind of staples you can drive in with a hammer, the latter are cheaper by a longshot - cheap staple guns won't handle this task.

    Now you're ready to start filling in.

    I use peat moss + organic bark (small pieces, like 1/4" to 1/2" if possible, or as close to that as you can get) + whatever compost I have (or can get from the city) + some "native" dirt if it isn't horrible and there's a place in the yard I had to dig some up anyway, say to level an area or whatnot. I do not ever ever buy cheap bagged compost or alleged "steer manure", it is always mostly sand and junk fillers. Get it from the city or your own compost.

    Don't fill it all the way up unless you are rich, but maybe 3" to 4", then start layering on your mulch.

    Over time your bed will fill up.

    If you have a particular problem such as caliche or rocky soil or clay you may need to add more than 3 or 4" worth of growing media at first, but eventually worm action and all that good organic stuff will lead to improved soil UNDER the bed as well as inside it.

    If you are laying out multiple beds, be sure to leave a good WIDE path between each bed. You will need to get in there with tools and a wheelbarrow for your harvest. Make your life easier and leave 3' wide paths.

    You probably don't need this advice, but someone else trying the same thing later may be glad of the information - 4' wide beds are not always the best idea. For those of us who are short or have limited range of motion (or both), a 3' wide bed may be easier for us to work with. I think my optimal width was 40" for a long time - but I'm older now so I may lose those extra 4" I have historically had, LOL!

    Hope that helps to give you a start. I can't help with anything specific to cannabis growing, but general growing - I've been doing that for over a half century, and for the first 2 decades of my life, most of what we ate came out of our garden. So general growing, I can help with, and I hope I have.

    Good luck.
     
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