Massive Garden Project, Need Advice

[grow_my_own]

Hi folks,

I have a dilemma and thought I would bring my question to the friendliest and most knowledgeable garden peeps in the world.... all of you.

Is there a formula for calculating how much soil/compost one will need for raised beds? I have been tasked with creating an organic garden at one of the wineries where I work, and I just saw the area where they have put in raised beds for this garden. It's a much larger scale than anything else I've done gardening-wise, and I am putting together a proposal and need to have some estimates on materials by the end of the week. I've been given different "ideas" by various soil vendors as to how to calculate the amount of soil needed; but to be honest, I could tell while talking to a couple of them that they were just really trying to sell me something. And no 2 vendors gave me the same answer.

So, I need the opinions of those who aren't trying to sell me anything.

I have a good list of materials and other supplies the garden will need, and I'm putting together my proposal. Boss just asked me for the proposal on Tuesday, and I have until tomorrow morning (Friday) to get it written up. Today is going to be a busy day of research, as this is the first day off I've had all week to even work on it.

Another issue I have in this new garden at work is gophers. When inspecting the area where the garden is being created, I noticed significant evidence of gophers. Is there an organic way of stopping them from getting into the raised beds? Here at home, I just line my raised beds with chicken wire in the very bottom when I first build them, and that has been very effective; haven't lost a single plant to gophers in 2 years. I'm not sure if that's considered "organic" or not, but it works. Would most of you consider this practice "organic"? Would the use of galvanized chicken wire be detrimental to the organic nature of this garden? Would lining the bottoms of the beds with chunky gravel have a similar effect toward keeping gophers out, while also assisting with drainage? I've also considered the possibility of lining the beds with broken glass--the beds are quite deep, at least a couple of feet in most spots.

I have been asked to keep the initial costs down as much as possible without sacrificing quality, but the owners of the business really do have the resources available to make this a really spectacular garden. I just have to give them a concrete, viable plan and some good numbers by the end of the week.

This garden is going to be really big. The raised beds are empty, and good soil will have to be purchased. The raised beds are built out of colorful rock, mostly granite, held together with concrete. There are 3 of them. The two outer beds are 10 x 29 feet, and the center bed is 10 x 23 feet. This is the biggest gardening project I've ever taken part in, and it's pretty much "my baby." We'll be growing produce that we use in the kitchen at work.

This garden is in hardiness zone 9b. My home garden is in 9a, so it is a similar climate to what I am used to.

Thanks to all of you in advance for any information, techniques, and advice you can share. I've been gardening in my own yard pretty much all of my adult life, but this is a huge undertaking. As an avid hobbyist gardener, having the opportunity to create something like this and get paid for it is like a dream come true.

 

[canesisters]

I can't help - but I'm excited to see what other folks have to offer. What a great opportunity!! Take picts.... you know we love pictures

 

[so lucky]

I have not heard anything about chicken wire causing problems "organic" wise, but it rust out in about 3-4 years. At least in my climate. But it works pretty well. How high are the raised beds going to be? 12"? Just multiply the length x width x height (in feet), to get the volume of the soil. Divide by 27 to get cubic yards. As discussed in another thread, purchased horse/cow manure is not necessarily organic, so be careful of your source for stuff like that.
Sounds like a big but fun undertaking. Good luck!

 

[digitS']

Grow_my_own, I brought my calculator but the square feet are easy. 10 (29) = 290 (2) = 580. 10 (23) = 230. 580 + 230 = 810 sq ft.

How deep? Too wide to reach across, . .

There is a common "soil" that is sold around here: 3-way mix. It is said to be 1/3rd topsoil, 1/3rd sand, 1/3rd compost. Compost is fine but those beds would require yearly additions. Annual veggie beds, that would be easy but perennial herbs, not so much so.

Wonderful! Will there be footings under these stone walls? I think galvanized wire is just iron and zinc.

Steve

 

[grow_my_own]

Oh, another question I have for y'all.

I always use oyster shell in my home garden to help control blossom end rot and add calcium to the soil. However, I have recently read somewhere that the produce from a garden that has been treated with oyster shell or egg shell cannot be considered "vegan." Not that being 100% vegan is a necessity here, but what other types of calcium sources are there which might be considered "vegan"?

 

[Ridgerunner]

I can’t help you. I don’t know the right proportions of the different components of the soil that would work for you. You can maybe chat with your county extension agent? If the agent is any good, he/she can hook you up with someone at your state land grant university that should be able to give you reliable information. Your time limit may make it rough though.


I don’t know if galvanized wire is allowed by the organic rules. You should have a local certifying organization that would certify someone as organic. The federal government has some guidelines but often the local certifying organization has some additional requirements. If you can locate your local organic certifying organization, they can give you some guidance. Again, maybe ask your extension agent for a contact. I know treated wood is not allowed here.


You can make galvanized wire last a lot longer if you paint it. I don’t know what paint, if any, would be acceptable to your local organic certifying agent. A roller usually works better than spraying wire, but there is still a lot of waste. Just be careful not to scratch the paint or the galvanizing. That creates a “holiday” that concentrated corrosion.


Organic can mean different things to different people. You have the “certified” organic where they have some pretty rigid rules to follow. Then you have people who feel organic is more of a lifestyle than a set of rigid rules. To me, it can be a nebulous term.


Good luck. You have a challenge in front of you but you probably know that.

 

[bobm]

When calculating the needed soil amount, one must also account for compaction of the soil over a period of time or the depth will shrink considerably as added soil is quite loose depending on composition. Take a container fill it to the top with soil, add water and see how much it shrinks. ( I would recommend talking to a structural engineer or a soil specialist). Also, most crops need neutral to slightly acidic soil for proper growth and production, so a soil test of the intended soil is needed too. Chicken wire is quite thin and rust away in just a few years, heavy plastic coated welded wire will last many more years longer. Enjoy the task !

 

[digitS']

If your soil is not alkaline - agricultural limestone (calcium carbonate). Dolomitic lime contains both calcium carbonate and dolomite (with magnesium).

If your soil is alkaline - gypsum (calcium sulphate).

I imagine that they are all considered organic.

Steve

 

[digitS']

One other thing that people have trouble with sometimes with bringing in soil for raised beds: "perched water table."

Cute term. It just means that the water cannot move easily from one type of soil to the other. It "perches" on top what is below the bed. Kind of floods the bed while the soil below absorbs the water very slowly.

This is not a problem here because there is so much rock in our soil but what I understand is that, with a little work, it isn't much of problem anywhere. You just do a little mixing of a couple inches of the native topsoil with what is brought in.

Steve

 

[ducks4you]

3 years ago I double-dug 4 raised beds, 3-4 ft. x 12 ft each, and I dug down 30 inches. The best ones were refilled with original dirt and rotted stall leavings, about 1/2 and 1/2. The other ones need more compost. I have had seeds start in my stall leavings (compost) piles, so I don't think that you can use enough of it.