What to fill a raised bed with???

Hi,

I’ve got some questions regarding the implementation of a vegetable garden. Any input or advice would be very much appreciated. My girlfriend and me are starting a small raised bed garden a few yards from our front door. We are going to grow herbs, lettuces, kale, peas, cucumbers, strawberries, onions, peppers, carrots, and beets. The vegetables that do best in shade would be closest to the wall. We also want to try the elm oyster garden patch from Fungi Perfecti.

The garden will abut a 6’ tall wooden fence that runs north-south, for about 7’, and extend about 10’ eastward, coming to a point, with a four foot slot going north to south a 3’ from the fence. The area looks like a C with a long, pointy bottom. My guess is that its about a 35 square foot area, and I was thinking going a foot tall. I have lots of cedar logs, so I would like to use them for the walls of the garden.

My main concerns are what to fill the garden with and how the dynamic between the garden and the soil underneath will work.

The soil in the yard is clayey, when we get rain, water puddles in depressions near the south end of the fence. Maybe 30% of the garden will be above where those depressions are.

Here is what I was planning:

I’ve wanted try hugelkultur to possibly regulate the any water under the garden, and because it just sounds fun. I was thinking of digging some trenches where the garden will be and dropping rotting logs and branches, and flopping the grass back upside down over the trenches to have a little more nitrogen with the wood. Is hugelkultur appropriate for our site? Then, cardboard over the whole area where the garden will be, for a grass smothering barrier. Then, fill the garden with layers of organic matter, trying to keep the nitrogen and carbon balanced. Would layers or a mishmash be better?

I don’t want to buy anything from stores. I like the idea of using local, available resources.

We don’t have any soil to fill the garden with, and I’m uncertain as to what plants will actually grow in. I’m imagining the garden as kind of a foot deep sheet mulch that will break down over time, that we will keep adding layers to and building soil. The seeds would be started in soil pockets. Is this a good strategy or not? Will the roots of the plants travel down through the mulch and into the soil below? I’m sure this is plant specific, but do they even go down that far? If so, won't the cardboard impede them from doing so?

I have available a pile of composted leaf rakings, about 5 or 6 cubic feet. It looks like good soil, with some decomposing bark scraps, leaves and twigs mixed in towards the surface. Pretty much unlimited horse manure, and a large pile of cedar chips. Lots of cardboard, a stack of newspapers, and one of those commercial plastic compost bins with about 4 square feet of finished compost, the rest of the bin is full of vegetable scraps. If I use horse manure, should I keep it towards the bottom? How much is good to use?

Any other ideas for materials that typically could be found or foraged to use for fill?

Some other notes:

The horse manure ranges from fresh to broken down. We also have 2 1/2 bags of pine mulch, and maybe 10 wheelbarrows full of dry or decaying leaves raked from this past fall.

We were also wondering if gophers or other burrowing animals could be a problem. Would it be advisable or not to cover the bottom with chicken wire, coming up the insides of the walls a little?

I depends on how much time you want to spend. I have formed raised beds with no siding out of aged horse manure and planted right into that no problem.

My plan might look like this.. Put down any sticks or logs, if you have a lot of them dig a trench to lie them in. Cover the sticks and logs with the most decomposed of your leafs. Cover all of that with horse manure and dirt from your trenches. If you have sod that you dug out flip it upside down and put that on top as well. Top the entire thing with your finished compost. Plant seeds and starts, then mulch with more leafs. I think you will get really good results from this.

One note, many people have problems with horse manure that has de-worming medicine in it. If that is the case for you consider leaving it out.

Good luck!

Rotten wood on the bottom-thats the hugelkulture you referenced.
Topsoil
Compost-a cubic yard of the stuff would go a long way. Figure 30 bucks. Have a truck?
Leaf Mold-the older the better, good and black
Manure-aged a couple of months, rabbit can be used fresh
Compost Tea will help give it a head start
Coffee Grounds-sprinkle them around for a little extra N
Grass Clippings-tossed with all the soil components or used as a mulch
Mulch-leaves will work just fine. a couple inches over the top of everything
Worms-they'll keep everything tilled and drained
Peat-if you would rather not spend the money, use a mower to finely shred up lots of leaves, just as good

Back in the day, farmers and growers would dig up the top few inches of forest floor to spread on their fields. Rich in leaf mold and humus, teeming with life.

Thank you HK! What I have been curious about is the order of layers when people describe configurations for garden beds, why certain layers are above or below others. For example, why would you place the leaves below the manure rather than manure and then leaves on top of them?

Thanks for the tip on the horse manure too.

Welcome to Permies. You found the right place.

Mix it all up, leave the top layer of leaf mulch. The microbes which will prepare plant nutrients like a diverse diet. If you don't mix it up, the worms will mix it up for you.

Thank you HK! What I have been curious about is the order of layers when people describe configurations for garden beds, why certain layers are above or below others. For example, why would you place the leaves below the manure rather than manure and then leaves on top of them?

You're welcome You want the layer of carbon (leaves, logs and sticks) at the bottom as they will help retain water and decompose over time. This will give your beds lasting fertility. I'm sure there are other beneficial things to this set up as well. On top of that you need a soil/manure layer because that is what plants like to grow in best. For one thing, pure carbon will use all of the available nitrogen, leaving none for the plants. The soil also has minerals, microbes and a proper structure for root development. I like to put compost on top of soil so that the compost nutrients will leach down into the root zone. The very top layer should be a mulch such as straw or leaves. This protects the soil from direct sunlight, wind, and erosion. It helps moderate soil temp and generally creates a beneficial micro climate at the root zone.

I hope this helps!

Yep, wood on bottom soil 'stuff' on top, awesome raised vegie bed, especially if you have to go 1 foot high.

Im surprised you say you have no soil. Im sure you do, its just sitting there beneath your feet Id assume, even if its just a thin layer, a scraping of top soil, you can whip it off and stick it up near the top.

and no, if youre planning on growing vegies, roots dont go down that far at all on most of them, so you gotta put your ready nutrients up the top.

Remember as things rot you'll have to keep putting more stuff in too.

Thank you all for the welcome and info!

You're right Philip, I dug the garden down a foot and now it seem like there is plenty of soil available.

I've got another concern--Please excuse me if these are silly questions, but I don't want to do something that adversely affects the garden. I went to pick up the leaf compost, and am not sure whether to use it or not. Underneath the leaves and twigs on top, the core of the mound was soil, pretty moist, dark, crumbly, but completely interspersed with roots (live) from some plant that I could not se. The thickest veins being about a 3/8" thick, the rest pretty fine. The pile was almost spongy due to the roots, not dense at all. I used the pick and broke it up, shook out as much of the roots as I could, and took half the pile.

I got the bigger clumps of roots out of the pile, but the roots really permeated the mound, so there are probably lots in the compost that I have. Is there a chance of whatever made the roots regrowing and taking over our garden? I couldn't find any plant connected to the roots. It seems like the roots were so efficient at taking over the compost pile, I wouldn't want the same to happen to our garden. The owner of the property told me that underneath where another compost pile on the property had been, the roots of the trees had moved in, so that he couldn't even dig there. There was a hedge about 5 feet away. Are the roots something to worry about? Or should I not have been weeding them out and have kept them in the compost for nutrients on breakdown? Did the plant connected to roots suck all of the good stuff out of the compost?

Also, the compost has lots of wood bits and twigs in it, maybe it needs to be balanced? I was also noticed that there weren't any worms in the pile, actually just a solitary one that I saw, I'm not sure what this means.

I don't know what kind of roots you have. In general, I wouldn't worry about it but you definitely don't want to infest your garden with an invasive from the get go. If you want to screen your compost that is fine. Otherwise I wouldn't worry about it. Worst case scenario is the garden struggles a little this year and does great next year. Worms are less active in the winter time. If you build healthy soil you will have earth worms.

HK, thanks! We put the leaf/wood compost in along with the hugel wood, dried leaves, sod, manure, veggie scraps, veggie compost, topsoil. Hopefully the vegetables will like it. We planted lots of vegetables and flowers, things are coming up and it's starting to look like a garden. Thank you all for the help.

We also made an upside down "v" shaped hugel mound on the west side of the fence. Looking at the drawings in Pauls article, I'd thought that shape with its steep slopes was so odd, but I am loving how the steep mound brings everything closer to arm's reach. I hadn't realized how useful that shape is. It was really fun to build too, reminiscent of Richard Dreyfus' mounds sculpting obsession in Close Encounters. We are growing herbs, blueberries, bush beans, radishes and flowers on it. The fence faces the back of the mound, so that side is shady, and we think (finally raining here in NY state) will be a damp microclimate. We planted radishes and bush beans on the top of the shady side to create more shade and contain moisture, and devoted that whole side to a hypsizygus ulmarius mushroom patch from FP. I really hope it fruits, the elm oysters sound so TASTY.

build your bed as you described but leave out the cardboard, if the grass is flipped root up, then you shouldn't need the cardboard..put the grass root side up right on top of the logs and put any compost or nutrients on top of that and then your soil from the bottom of the hole on top..and plant right in that and then mulch well around plants but not over seeds or plants.

should work well, I have clay soil..

Brenda, thank you very much. That make sense about the cardboard. We actually left it out but I think just because we had lots of other stuff. The garden is doing well, it's small, but bursting with good eats.

We've got the hugel cedar-framed keyhole bed that I was asking all of the questions about, and a hugel mound-style bed. We are planning on expanding the garden to take over a 50'x40' section of the lawn with more hugel mounds. I like the mound shape. I've had a hard time finding info on water harvesting on uneven, or level terrain. Our lawn doesn't have a particular slope, it undulates a bit, so there are lumps and depressions throughout. Anyone have any thoughts on bed alignment and shape for capturing water and sunlight, regarding which consideration takes precedence, and issues of trade-offs and sacrificing one for the other?