Garden Construction?

[Niele da Kine]

I'm setting up a new raised bed garden area and have been contemplating how other folks set up their gardens.

How do you set up your initial garden site? There's a lot of information about how to plant seeds and raise plants, but what about the initial setting up the gardening area? What have you found to be the best methods for your area? I'm sure there's about as many 'best methods' as there are gardeners, but what's worked for you?

After over enthusiastic string trimmer (aka 'weed whackers') took out too many of my garden plants, I put in a raised bed to define the garden area and keep the weed whackers at bay. That brought up the discovery that with a raised bed garden, it uses a lot less water and fertilizer since only the area that has plants gets watered. It's also a lot easier to reach the weeds, so now the gardens are getting taller than the first one.

This is the newest raised bed garden. The first thing is to pick where and we have problems with really aggressive tall grasses, especially when they're on a steep hillside. The plan with this area is to remove the grasses (mostly Guinea, Reznor, cane & elephant grasses) and terrace the hillside with the garden. So, this is the new garden site:

After several days of extreme grass removal, it got a little bit cleared out. It's been handy having two sheep on the other side of the field fencing. The grasses are cut and tossed over the fence where the sheep eat them. They've been in the fenced area (it's not quite a 'pasture' yet) since last August and have made a huge dent in the tall grasses, but there's still a lot of work for them to do before it's anything pasture like.

Good weed eaters! We only have two of them, Cypress & Flower, since we don't know how many sheep the fenced area can actually support once they get the tall grasses eaten down. They seem to like a wide variety of weeds, not just the tall grasses.

After three or four days of 'weeding' it has a lot less of the tall grasses in the area, but it still isn't a garden yet. Weeding with a pick axe is a lot of work and we have discovered that a potato fork works amazingly well for removing grass clump root balls. It's all deep soil, which is huge on this island since a lot of folks just have lava rock so I suppose we shouldn't complain about digging out massive root clumps.

It's still not done, this is the current state of 'garden building'. The concrete blocks work better than the tin roofing so we're using the all concrete blocks on this one. The other raised bed garden with the red tin roofing at the front is about a year old now.

There's steps between the two gardens and this new garden will be longer than the other one. Taller, too, although that's not readily apparent from the picture.

The plan is to dig out behind the concrete blocks and put in weed mat. Then put a screen over it (we have bunny hutches and a wire floor plate for the bunny hutches makes a dandy screen for garden soil) and then fill with the soil cleared off while leveling the path behind the garden between the garden and the sheep fence.

The concrete blocks are just set on soil, no real foundation, so those bits of cut off metal fence posts (we found them at our local dump, I have no idea why someone would cut down fence posts that much) are set into the holes in the concrete blocks to hold them together after the soil is put inside. The big wooden fence posts in each corner are to keep the bricks lined up and to support the chicken wire fence around the garden. Otherwise the chickens get into the garden and mess it up.

Since we're an island and anything imported is pretty pricey, the fertilizer for the garden will be bunny 'berries' since we have the bunnies and they're always making fertilizer for us. The top layer will be about half bunny manure and half topsoil from the other parts of the yard. Because we have really high rainfall (about eight to ten feet a year) 'bio-char' (charcoal without any lighter fluid chemicals) is added to the garden so nutrients can be trapped in the charcoal for the plant roots to find. Rather like a charcoal filter for drinking water, the charcoal traps 'impurities' (i.e. nutrients). We also add oyster shell to sweeten the soil since it's somewhat acidic here. Using lime just washes away but the oyster shell stays put from year to year.

There may be some way to set up a rainwater irrigation system, although it may not really need more water when it's raining. Mostly it would be because that's where the roof has been draining and the water has to go somewhere. But, that's something to figure out later, I suppose?

So how do you construct your gardens?

 

[Ridgerunner]

I moved down here form Arkansas in 2018 and lost that growing season. And I moved to suburbia so I have little room to work with. This shows what I have.

It is 8 raised beds 4' x 8'. I have a real problem in a lot of this with nutsedge. I'll just say it is a problem once it is established. It was established. That's what you get for living on a former marsh.

I started by laying out the beds and building them with 8' x 12" x 2" treated lumber. I left about 3 to 3-1/2' clear around each one. My next step was to remove about the top 5" of soil in each bed to try to at least get the nutsedge problem under control. It still shows up but I can handle it.

I put landscaping material down to knock out the grass and weeds, at least temporarily. Then I filled the beds with what they call garden soil down here. It's supposed to be a mix of sand and compost but had a lot of shredded bark in it. No clay. It is meant to be dug into and mixed with your native soil but I did not want to mix my seeds and other stuff with it.

I had a soils analysis done and it was horrible. pH of 7.9 and no nutrients. So I got clay from a place that sells clay to potters. $700 for one ton and I had to haul it myself. It's pure clay but gets its color from the mineral content. I got it all of one type of high calcium clay. If I had it to do over again I'd get maybe 1200 pounds total, that would be enough, and of three different mineral contents. But the soils analysis comes back good for all nutrients except nitrogen, That leeches out of the soil. The clay seems to hole the other nutrients well. I added a lot of elemental sulfur, it took a growing season and doing it again but it got the pH down to the low 6's. A lot of sulfur. And I dig in a lot of compost every time I plant it.

After a while grass, nutsedge, and weeds started growing up through the landscaping material between beds so I covered it with cardboard, then covered that with what they call pine straw. That's long leaf pine needles. It lasts for a while and then needs to be replaced. That's going to be a constant battle with cardboard and pine needles as you can see from the photo but I don't want to be weed-eating or mowing in there. That tosses weeds, grass, and weed and grass seeds in the beds. I can't get wood chips down here, they won't sell them. We have a serious Formosa termite problem, don't want to encourage them.

I think that's the basics. Good luck!

 

[Artichoke Lover]

Sorry not much help here. The land we bought was old farm land. If we want a new garden spot we generally just mark it off and till a few times. I do want to get some boards and edge the flower beds by the house but that will have to be a project for next year.

 

[Niele da Kine]

Lovely garden, RidgeRunner! If we tried using boards to build a raised bed garden, they'd be rotten within two years. Even if they're treated to start with or some sort of 'rot proof' lumber like redwood, even if we could afford redwood. Why do you have numbers on the raised beds? Is there a garden map that goes with the numbers?

I'm jealous, Artichoke Lover! It'd be great to have flat tillable land. Do you have trouble with weeds over running it or folks with string trimmers taking out the edges?

 

[flowerbug]

i've written most of this before here several times, but since you asked.

observation for a season is generally the start i'd like to make. unfortunately that wasn't what took place here as Mom didn't know she was going to garden until after they'd built the place and things were all in the way. observing the wind and sun and the water flows in a space.

here the gardens out back were put in the low areas that flash flood. if it were up to me and i'd known i was going to garden i'd have brought in more fill to get better garden soil and to get above the flash flood stage. the front gardens and the north garden are on top of fill brought in.

the only reason we have raised beds here in the main vegetable gardens is to get above that flash flood stage. i don't like them and consider them a waste of space, time and efforts on top of the money spent to bring in the materials (for us rocks). every edge is work, every fixed pathway is work, every bit of hardscape is in the way or work or both. if you want vegetable production you want to maximize the use of the space and allow for the most flexibility in rotational planting. edges and pathways get in the way of that.

 

[Zeedman]

I won't compare my garden to yours, @Niele da Kine , because between geography & climate, our gardens have little in common. So I'll just address the concerns I see with your garden location.

The biggest problem I see is not the grass, but the slope. That is a very steep hillside, and erosion - or even collapse - is a serious issue. That over-grown grass (and wow! is that monstrous!) may be what is holding the soil together. To keep that soil from being washed away in heavy rains, you will need strong retaining walls, and good drainage. I'm assuming that the steel sticking up from the bricks will be run down through the stacks?

I'm curious how much rain you get in your location, I know some parts of Hawaii get annual precipitation measured by the foot.

 

[Dirtmechanic]

Cypress and Flower are cute!

@Zeedman has a point about drainage and structure. One caution is about accidently creating a weak walled water holding tank upslope of a building. The hugelkulture crowd talk about the risk of damming, because what seems like a small amount of water can weight out as many tons, and a sudden release would be unfortunate for everything below.

I read about the grey soils versus the brown and red soils on the islands. Does it rain a great deal there or are you on the dry side? So much rich soil. You may not have that much need of fertilizer! Which color soil do you have? The islands can have many different types from the soil maps I have been seeing. I recognize it is important to know, and that you have an opportunity to go dig some up from somewhere else if you need something a little different.

One thing @flowerbug said about observation is really important. Flower knows about the grass being tasty. Grasses (corn) like humic materials, and I would think that soil has a lot of it given the preferences of the plants currently growing. Its a soil type clue for sure so look around and discover the plant types and read about what they prefer, as it will help you utilize the free local resources to the best advantage of your crop choices.

One overlooked fertilizer source is protein. It's a component in a lot of the great organic fertilizers such as manure. The nitrogen values are about 6% of the protein content depending on the material. Beans work. Soybean meal is almost half protein. Its slower though, so plan ahead. Let me know about the soil. I find it incredibly interesting. The climate is directly related to the subtype so my curiousity makes me ask about weather. I know the lee side of mountains can be drier than the windward side so your micro climate is interesting to know about relative to your soil and what does or does not leach away or get pulverized over time.

 

[Niele da Kine]

Observing for a season is the best, Flowerbug, if one can. Is it too much work to flood proof your garden area now that it's already a garden area? Would dikes work? Although that would require a lot of some sort of material to make the berm.

No worries, Zeedman, we've got drainage up the wahzoo. You know how on the mainland folks do a 'perk test' to check for drainage before they buy a property? I've heard they dig a hole and pour a 55 gallon drum full of water into it and then time it to see how long it takes to drain? That's not done here in Hawaii since the water doesn't stick around long enough to be measured. We only get about eight to ten feet of rain a year so we aren't in a particularly wet area. Unless we get several inches of rain per hour for a few hours in a row, we never really worry about flooding. Even then, the house is up off the ground so any water would just go under it, not sure how far it would get before it all got sucked into the ground.

The soil goes from dark brownish black to a reddish orange depending on how deep it is. The top foot is brownish black going to dark brown, then dark brown to reddish brown in the next foot and then reddish brown to orangeish brown in the next foot after that. It also stacks up really well. Even the Highway Department leaves what looks to me like much too vertical of cuts when they put a road through a hillside. But, other than the occasional rock falling down onto the road the hillsides seem to stay up.

Half the purpose of this garden is to be a retaining wall. It's difficult to keep the hillside mowed because it's too steep, which is why the sheep. This new garden is in the area between the house and the sheep and on the steep part so once it's a garden, we won't have to try to figure out how to mow it anymore. Kinda like they terrace hillsides in China except this is just one terrace and not a whole lot of them.

Yup, the metal stakes will go into the holes in the concrete blocks to hold the whole wall together. Even though the soil stacks really nicely, it's still good to have the blocks held together with the metal. It's just dry stacked concrete blocks so the metal will hold it together. Also, since it's dry stacked (not mortared together) any water will leak right out.

There is a roof drain right near the new garden, if the downspout were put through the garden, I dunno what that would be in 'inches per year' of rain. Probably triple what it would usually get? The high rainfall is why the oyster shell is used to lower the acidity of the soil instead of powdered limestone. The hydrated lime just washes away while the oyster shell stays put for awhile. Some folks use coral or opihi shells after they've eaten the opihi but since we have some oyster shells for the hens, we just swipe some of that when setting up a garden.

We will use bunny 'berries' for the fertilizer, Dirtmechanic, since we have them and they don't cost anything. The bunnies are angoras and are fed high protein rabbit pellets along with fresh forages so hopefully they have a higher protein manure than most rabbits? If we do get soy meal, then that's fed to the rabbits before it gets to the garden. I think that's labeled as 30% protein? The bunny pellets are 18% but they're fed to the bunnies before they get to the garden.

 

[flowerbug]

yes the coarser volcanic ash usually drains pretty well, 8-10 feet a season of rain is about triple of what we'd get here (and for the mainland and eastern area of the country this is considered pretty wet compared to the western states).

nutrient and garden topsoil retention with that much rainfall is always going to be an issue.

almost all the soils around here are clay, sand or a mix of those with not too much grit or small rock. pretty much the opposite of what you have there. luckily the tropical plants will be adapted to this (the nutrients are held in the plants, roots and living creatures and not so much in the soil.

really, when you are in that kind of a climate you can do some small scale gardening on the ground level, but with so many tropical fruit tree and other species i'd go with those and aim for a food forest. trying to always keep back the surrounding growth from shading a garden area would be a ton of work. why fight nature to that extent?

we have scrub trees/poplars that can grow rapidly if not knocked back every three years or so. in an area that didn't have a winter it would be needed every other year or even every year. that's a lot of work!

our property isn't suited for being upgraded now because so much of it is hardscaped already. i do have a berm in place. check out www.anthive.com for details there are plenty of maps/water project and other views there. it is vastly different than where you are at. flat, flat, flat...

 

[ducks4you]

Many people construct their raised beds to be permanent fixtures. I used to do this, but I now don't. I use 4 x 6 pieces, pound pieces of recycled rebar OR wooden pieces on the insides and outsides and corners to put them up so that I can take them down. I have observed that the edges and corners of my beds compact no matter how much compost I use. Taking them apart allows me to work the soil so that I can grow completed in the bed.
Otherwise, you will need to dig out the sides and corners. If you don't mind doing that, then build to keep.
Just some FYI.