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Raised bed dries out too quickly.

11 years ago

In an earlier tread kimmq posted the following

"2) Drainage. Dig a hole
1 foot square and 1 foot deep and fill that with water. After that water drains
away refill the hole with more water and time how long it takes that to drain
away. Anything less than 2 hours and your soil drains’ too quickly and needs
more organic matter to slow that drainage down. Anything over 6 hours and the
soil drains too slowly and needs lots of organic matter to speed it up."


I have a 4X11 ft concrete block bed that dries out too fast. Three seasons ago I originally filled the bed with 1/3 vermiculite, 1/3 peat moss and 1/3 compost(cow, cotton burr and chicken litter). From the beginning I've had problems keeping it uniformly damp all the way to the bottom of the bed. In dry weather the bed will dry out all the way to the bottom and is then is very hard to re-wet. I've added leaf compost each year. I recently tried the procedure that kimmg recommended above and all of the water ran out in less than 15 minutes. I also filled a jar half full with dirt from the bed and shook it up with water. It separated out with about 10% sand, 30% of what appears to be organic matter that sinks and about 40% floating material.


I also sent a sample to the Louisiana extension service. The results showed very low nitrogen, but high to very high phosphorous, potassium, calcium, and other minerals

Kimmg's recommendation with fast draining soil is to add more organic material. I don't see how in this case this will help. Most organic material will add to the excess minerals that I already have, and in any event the bed is already 70% or more organic material. I can add peat moss but if the bed dries even a little the peat moss is extremely hard to re-wet.


Can anyone suggest a fix?


Comments (27)

  • 11 years ago

    You started out with way too much oprganig material and not enough dirt.

    Peat moss is extremely hard to re-wet if it dries out. Don't add more. To help rewet it, add a teaspoonful of dishwashing liquid to 5 gallons of water and distribute it evenly over the bed. It's will \reduce the waterproof characteristics.

    Fast-draining SANDY soil can be helped by adding compost. Your bed is almost nothing but compost. Add about 25% real dirt, preferably some with a lot of clay in it, and you will do better.

    To keep the bed from drying out, use drip hose and cover it with mulch.

  • 11 years ago
    last modified: 11 years ago

    Kimmq is talking about the Earth's native soil and you are talking about "potting" soil, very different things with the same name. Such is a test for too little drainage, usually in a clay soil. Just read the very first line from both the above replies and you'll have a good answer.

    I garden with sand and compost, and very-heavy-percentage compost is an advanced topic and in most climates it won't work well. It's not normal; it's remedial.

  • 11 years ago


    I'd have to comment that the mix OP is using is used by many for raised bed gardening also. So in that respect, he is following what many others have done but not getting similar results.


    The leaf compost is some organic matter but I wonder if you just put them on top (top-dressing) or did you mix it in? Although it started out as Mel's Mix, if you began adding and treating it with other composted materials, I think you would eventually get to a situation like others have done -- growing in compost (or at least, growing in something that has less and less peat moss percentage -- which is one of those ingredients that is harder to rewet just by letting water pass through it).




  • 11 years ago
    last modified: 11 years ago

    Woodchips.

    Woodchips will soak up, and hold moisture, then they will release it back like a wick. They are mostly cellulose, so they won't quickly increase minerals or nutrients over the short term. They are irregularly shaped so they provide 'pockets' for both air and moisture.

    They are organic matter, but they decompose very slowly, giving them some of the same practical characteristics as inorganic matter.

    They promote fungi, and host a plethora of microorganisms... nurturing a healthy soil web.

    When using woodchips, you must add nitrogen. They require the nitrogen in order to decompose. Much of this nitrogen will get 'locked-up' by the chips. However, as the wood breaks down, the nitrogen will be slowly released back to the media, thereby offering a long-term constant source of nitrogen to your low-N bed.

    In the beginning, you'll need to add a little extra N (some for the chips to use, and some for the plants.) If, during the growing season you add N in a soluble liquid form, it is immediately available to roots, and the plants will find it easily enough. You just have to learn how not to over-fertilize. It's not difficult, dilution is the key.

    Anyway, this is what I would consider. Some will disagree, such is life. Do not substitute sawdust for the woodchips. Sawdust has its uses, just not in this instance.

  • 11 years ago

    Organic matter does not sink in water. I have not even seen wood chips do anything but float so what ever was in that soil mix tested that sank was not organic matter. 1/3 vermiculite in any growing mix is too much, something around 10 percent is adequate.

    What is the depth of that 4 x 11 planter? Something 6 inches deep will drain much more quickly than something 12 inches deep.

    kimmq is kimmsr

  • 11 years ago

    What everyone said. You made a giant pot and it has to be watered constantly like a pot. :-] Get some soil mixed in there and things will be better.

  • 11 years ago

    Try adding cheap cat litter with no additives. This is dried clay and will help bring your soil to more of a loam texture and clay holds water just keep it below about 25 percent in volume.

  • 11 years ago

    Some of those litter materials may be expanded clay but most are ground corn cobs or something similar, organic matter. Clay, a mineral, does not hold water but its shape does prevent the easy flow of water.

    kimmq is kimmsr

  • 11 years ago

    Tell that to the shrinking-swelling clay here in Missouri. When it dries out there are cracks you can put your hand down into. When it rains they swell shut. You bet it holds water. I'd be glad to send anyone a truckload of it in exchange for anything you have that is not clay. :-D

    The cheapest cat litter is usually the gray clay stuff. It's very heavy and you can tell right away that's what it is. Although I would add soil to the garden rather than cat litter for various reasons.

  • 10 years ago

    Like most everyone else said, you want soil in a raised bed. Exotic recipes are a complete waste of time and money unless you are selling a book about gardening with raised beds using exotic materials.

  • 10 years ago

    Yeah. Who's that guy with all the recipes - shampoo and Coke to spray on your plants, and diapers in your tomato holes. Ugh.

  • 10 years ago

    Clay is NOT an exotic recipe, instead it is an integral part of a good loam. The microscopic particle size attracts cations that replace the hydrogen ions on the surface thus becoming a food bank for your plants. Thus it is measured the cation exchange capacity or CEC of your soil sample. Also the surface of the molecules adsorb water which is then used by microscopic root hairs. This is why it should be about a 20 percent amount homogenously dispersed with the sand, humus, silt and organic matter.

  • 10 years ago

    Oh please, kitty litter is most definitely an exotic material that is completely unnecessary for a raised bed. It's calcined clay or partially calcined clay btw. It's not just clay like it was just dug out of the ground.

  • 10 years ago

    I will stop commenting as evidently I know nothing, sorry to ruffle your feathers. I do know that I purchased a bag of litter that was organically certified to be 100 percent natural fullers earth but then again I am sure it must have been labeled in error. My sincerest apologies and good gardening.

  • 10 years ago

    I would take issue with kimmsr's drainage test. I have also read it elsewhere. It sounded so odd to me I went outside and tried it in my garden. (Native loamy soil with many years of compost additions.) The hole drained in 4 minutes on the second filling. (3 minutes on the first).

  • 10 years ago

    Hold up there Gregory, no one said you knew nothing. Your description of the action of clay particles is spot on. I can't speak for nil13 but there have been a number of ingredients discussed in the thread so the clay litter may not have been what s/he was referring to as 'exotic'. In any case, around *here there is so much clay it would be silly to buy it as cat litter, but if I've learned one thing, it's how much each of our regions differ. I know there are places you can't find clay soil anywhere around, so a bag of cat litter might be just the ticket. It should not be the first thing one reaches for without investigating. It does have a big env. footprint compared to local soil: it's dug up, roasted in a kiln, crushed, packaged, shipped (very heavy) and then you throw away the bag. I would just recommend that people try to use locally sourced materials for gardening as much as possible and keep these things in mind. I have no doubt that it does what clay does when mixed into the soil. And I hope in turn you would agree that there is a tendency, naturally brought about by the magazine snippet and sound bite culture, to glom onto the latest 'secret recipe' to 'fix' the garden, without digging deeper to find out what's really needed and how it might be provided differently but just as effectively, with less of a footprint, using local, cheap or free materials. That's what I really meant to say.

  • 10 years ago

    Excuse my rant, I am not normally argumentative but at least get the facts straight first then I am open minded.

    One thing, calcined does not make anything exotic as it means that heat is used to drive out the water. not a bad thing. And yes, we do have clay but I figured it was harder to take wet sticky clay and try to incorporate it into my beds, thus the litter.

    As with everything it is, Caveat Emptor.

  • 10 years ago

    Definitely no fun working with wet sticky clay. Before mine had improved very much there were only a few days in the spring when the moisture was just right so you could dig or till it without it being a disaster. It's a lot more forgiving now. A couple times I have built a compost pile over a new or fallow bed and layered clay between the compostables to get it incorporated easier.

  • 10 years ago
    last modified: 10 years ago

    The way I look at it, if it doesn't get sold by the cuyd and delivered in a dump truck it's exotic. This is soil we're talking about not container media.

  • 5 years ago

    I’m just guessing The word exotic was used to be an attention getter and it certainly was. I believe what the what the composer of that text was truly talking about was the addition of certain items which I have used. Some

    Bing kelp meal, bonemeal blood meal, green sand, (can’t remember any more, but there were about 4 more) some powdered minerals from rocks. All of this was added to Pete moss, Vermiculite my home brown compost no animal waste compost such as, newer or chicken manure. It was strictly grass clippings and leaves and whatever else I can throw in it it wouldn’t attract ants. It was very expensive to put together I was so excited. I emptied all my pots and refilled all of them with my wonderful new body style and put my new plants back in it. It’s been three months now they’re not growing or looking lush and green and wonderful; they are living. Finally I started putting miracle grow on them and now they’re beautiful but that would’ve happened with the quality soil I bought from Lowe’s. I also believe that would be referred to as an “exotic potting soil”.

    I also believe that, that’s what the person meant that used the expression “exotic potting soil“for the first time and all of these comments or something similar give or take a few additives.

    I got my exotic potting mix recipe from savvy gardeningI got my exotic potting mix recipe from savvygardening.comI got my exotic potting mix recipe from savvygardening.com on the Internet. The owner of this website lives in Canada. I live in coastal Louisiana, Baton Rouge. I tried and tried to get her to ask if she thought this recipe would work in the deep South. You never can get her, she doesn’t respond. I just figured since it was such an intricate recipe she would have taken into account a drainage issue that all states share, since I couldn’t get her. The The only worry that I had was that the drainage would be wrong because I had never worked with that much Pete Moss, but it did have almost equal vermiculite so I figured it would probably drain really well. I was right; it drained beautifully thank goodness. Louisiana is a third rainiest state in all of our United States. We are right behind Florida and Hawaii.

    I now have a very large city garbage cans filled with Pete Mas vermiculite vermiculite and my compost plus a very long list of additives so next time I make the recipe( b cause I got to get rid of this stuff) that I will cut back a bit on the amount of vermiculite.

  • 5 years ago

    Please excuse my many typos especially the one that says my wonderful new body. It should say my wonderful new potting soil recipe. I don’t know what’s wrong with my iPhone today it’s acting up.

  • 5 years ago

    Peat moss is a soil amendment. Pete Moss threw a no-hitter for the Dodgers in 1937. :-P


    Hanging around here for a few years, what I've learned is that the 'secrets' to successful gardening are pretty simple. With respect to potting mix, the main thing that made a big difference for me was that 1) you can't use regular soil in a pot (with rare exceptions), and 2) the potting mix should be coarse, which a lot of commercial mixes are not. Once I started paying attention to those things, my plants grew great.


    Similarly for garden soil, I found that simple inexpensive organic matter - compost - does the job as well or better than anything else. When I filled my raised beds (I'm further raising up old ones that are only a few inches high) I used local soil with lots of compost added, period. People seem to think if something like compost is good, then more must be better, and nothing-but must be awesome. Grampa used peat moss and lime so I should too. Turns out not everyone needs lime, and peat moss is hard to wet, produced far away from most places and shipped, and only somewhat sustainable.

  • 5 years ago

    Thank so much for that great reply and. . . my reply to you is “hmmmmmm”.

    So much to say, and I’m so bad at typing it. Real slow! Wish we could go someplace quiet and talk alllll about my dried out, 3 ft tall, 4 x 8 wonderful raised beds that my sweet husband had built for me 12 years ago after I broke my back!

    I'm always trying to get them (the raised beds) to hold onto the oceans of water we put on them so they can utilize what I feed them. Also, 12 years ago we didn’t go without rain for 7 weeks and have the temps steadily in the high 90,s. Before we got a good rain! It’s drastically changed here.

    The fact is I’m tired. Even too tired to “re”-hook up and up grade my drip irrigation that we (for some reason) took out. The reason being I’ve just about accepted the fact that 1/3 of what is in those 2 huge beds needs to be earth-soil; not nursery soil, and it overwhelms me because right now they’re about 99% nursery soil.


    Ide love to know how u build your potting soil. What we have here is all garbage! That’s why I decided to make my own!!!!! Spent a small fortune on alllll the amendments that were in the recipe and I KNEW I would have THE PERFECT

    potting soil. Well you know the rest.

    Would REALLY like to know how you “do” your potting soil. What do you use to make it coarse??

    do you mix it w YOUR personal compost?


    Most IMPORTANTLY, where do u live? That’s huge! Can’t wait to hear back.

    bye :)

    Rachel Williams



  • 5 years ago

    Also thanks for the heads up on Pete Moss and

    pete moss. :)

  • 5 years ago

    Look up "gritty mix" on this forum or the Containers forum and you'll see what people do.


    I have access to a lot of materials since I have a sawmill (generates a lot of woody waste) and a chipper shredder. I can chip up bark and sift it to get 1/4-1/2" pieces which I then add to commercial potting mix to make it a bit coarser as well as stretch it with free material. I used to put in a lot of my own compost but it's too fine, so I sometimes sift that through chicken wire and add the half composted leaf and stick bits to the mix.

  • 5 years ago

    Add REAL DIRT from the earth. All you are using in your bed is/are “SOIL AMENDMENTS” but u have no SOIL.


    You have created a “planting mix”.


    Works well w potted flowers and veg. With saucers bc we water those more frequently and use liquid fert.



    Raised beds are a “whole different animal”. Like horses and donkeys.

    similar but different. (but NOT as different as horses and bricks.

    30-40% “earth dirt”.

    good luck😵