New raised beds and container gardens, What soil do you use? For the urban gardener

Mi Gardener

New raised beds and container gardens, What soil do you use?

Currently I live on a plot that I don't own or control but I would like to have a raised bed garden. What is a soil i can use and create without using the native sprayed and fertilizer lawn soil?

Torey

@Mi Gardener I would suggest that you use containers for all of your gardening if you have no control over what is being used on the ground. Its amazing how much you can produce from a container garden.

You can build beds with bottoms and put "feet" under them. Something like this. So they aren't right on the ground.

There are a variety of store-bought growing tables, benches, etc. that have taller legs. Raised beds like the one above are easy to attach hoops to for extending your season with row covers or attaching trellises to, for vertical gardening to increase your harvest.

In an urban setting you may have to buy bagged top soil and compost until you are able to produce enough compost to top up your beds. Check at garden centres in your area to see what soil is available. You might be able to have a truck load delivered instead of bags if you have room for it.

vickeym

I am a far north gardener with horrible or no soil, so I sympathize. We have mostly clay and gravel with a very thin layer of topsoil and in some places some mossy cover.

If you have access to chicken bedding anywhere, it has made most of my soil so far. I mix it with the clay and topsoil and as I have more compost made I keep adding to it.

The chicken manure has to be well aged or it can burn the plants. If there is rabbit available that is as good or better and doesn't need aging like the chicken does.

Mi Gardener

@vickeym yes but I am concerned about the manure having a high potash content that causes weeds and bug problems. Have you ever heard of the Dr Carrie Reams method of soil analysis?

Mi Gardener

@Torey I was looking to do a cinder/concrete block raised beds like what Lynn did in CO. Yes topsoil is what it's called outside of the landscape stores

LaurieLovesLearning

I moved this discussion to an appropriate category.

Please continue...

Torey

@Mi Gardener Your description of the land the beds are going to be on led me to believe you wanted something that wasn't in contact with the soil of the ground/lawn. Even though you are building a raised bed, the roots can still reach down into the soil below and any soil below may contaminate what you put on top.

Another caution is regarding cinder blocks. They are often made with fly ash or "cinders" added to the concrete mix to make a cheaper, lighter product. The fly ash may be contaminated with toxic chemicals or heavy metals which could leach into your beds. Concrete blocks are a much better option.

Good luck with finding a supply of soil.

VermontCathy

Check the book Square Foot Gardening by Mel Bartholemew. He was an engineer (now deceased) who experimented with different mixtures of raised-bed soil, and came up with "Mel's Mix", the optimum solution he tested.

It's one third good compost, one third vermiculite, and one third peat moss. The latter two ingredients are easily purchased in bags from a garden supply store. The compost source will depend on what you have available locally.

I have experimented with his mix and it does work very well, supplemented by additional compost every so often. It's too expensive for a large garden, but perfect for an urban garden consisting of a few raised beds.

dipat2005

@Mi Gardener I too love Square Foot Gardening and when I first decided to try gardening, I researched soil and made my own for a while and then went to a Home and Garden show and I learned that the places here that sell the best soil is a place that sells by the yard or the bag. I have a 14"x 6- or 8-foot garden bed that my son made for me last year. I also have 1 Swiss Chard Plant that started out very small but now I can harvest from it. Surprise!

Mi Gardener

I was watching the high performace raised bed gardening with the concrete blocks and the secret soil mix where do I find the receipe for this secret soil mix?

JodieDownUnder

@Mi Gardener hi & welcome to the forum. I’m in Australia but I’m sure your area would provide the same product & service like I just tried for the 1st time. All my raised beds (hardwood timber) needed a top up & I have used all my compost & manure supplies. So I went to a local nursery/landscape supply centre & asked if I could check out their soil- compost supplies. I had a look, touch & smell. Then I grabbed my pH test kit from my car & checked, all good between 6 & 6.5. The mix I selected was 70% sandy loam mixed with 30% mushroom compost. I ordered & paid for 2 cubic metres to be delivered to my place.

I topped up all my beds, left it for a week & then planted seedlings into the beds. That was 5 weeks ago & I’m already eating lettuce, rocket, Asian greens, cabbage etc. I still have a bit of soil left over & now I’m giving all my fruit trees & anything else a top up of this soil mix followed by a heavy layer of mulch. Very happy with the results for a quick fix.

Torey

There may be an issue with getting peat for making that blend for Mel's Mix. Even here in Canada (one of the biggest global suppliers), it was difficult to find last year.

This year, Sunshine Mix (blends commonly used for seed starting, hanging baskets, potted plants, etc.) is only available in two of its product line this year, due to supply issues which may be due to the peat shortage.

VermontCathy

@Torey I think coconut coir would work fine as an alternative to peat, if you can find it.

Long term I expect to see use of coir become much more widespread, because it's a renewable resource.

Unfortunately it is difficult to find today, especially if you are looking for enough to create a garden bed, not just a tiny bag to fill a small pot or two.

heirlooms777

@VermontCathy @Torey just be careful as coconut coir has to be processed correctly or it will take all the magnesium and such out of your soil

VermontCathy

@heirlooms777 This is the first I've heard about magnesium deficiencies from coconut coir. Could you provide a link that explains the problem and the solution in more detail?

Torey

@VermontCathy I hadn't heard about magnesium deficiencies from using coir, either, but when I had a look right now, there are several sites talking about it. However, they are all hydroponic cannabis growers and the majority are trying to sell a cal-mag supplement.

This site gives a better explanation than I can.

https://www.trees.com/gardening-and-landscaping/cal-mag-for-plants

I wouldn't think this would be an issue if you are using coir as a soil additive in combination with compost, manure, soil, etc.

vickeym

https://community.thegrownetwork.com/discussion/comment/921720#Comment_921720

No, I had not heard of him. Went looking and found a "little" bit. I did not understand much of it yet. Will have to try reading it over a few times and see if it makes a bit more sense after reading it a couple times more.

heirlooms777

I am going to build a square foot garden over cement, something I can take with me if I move from this location. I rent, and they don’t want to mow around it in the grass and have it south of the garage over the grass. The south side of the garage receives the most sun where I live in the states.

I work at a local organic “city CSA” that makes beautiful vegetables compost (another post coming about “to till, or not to till” ;)

So the question is, do I use 100% vegetable compost, or do I mix it with some of my mom’s sandy soil from the forest in her backyard? I know Mel’s mix was 1/3 compost, 1/3 vermiculite, 1/3 peat moss (did you know Mel of Square Foot Gardening passed away?). I can use my extra scrap angora wool (first coat of the beauties, we call it “art wool”) as vermiculite, as wools (like angora bunny wool) absorb water; I also have some extra sheep wool from a local farmer. I don’t know, what do you recommend? I still might put in some peat moss (we get it from Canada here in Michigan) and vermiculite, just not sure of the amounts, or what blueprints to use to build the deep (four foot or deeper) square foot garden. (Also sad because it is going on the west side of the garage over cement, so not great sun or depth of dirt for the roots.)

For coconut coir, I heard about magnesium absorption problems from a seed starting / micro green class. It was something like soaking the coconut coir with epson salts(?) or something like that before using, so it doesn’t absorb the nutrients from the soil. I’ll look it up. The speaker suggested that a sort of local peat moss is better for the environment than coconut coir, but if you don’t have something local (like people living south in the states), coconut coir is perhaps more economical once it has been processed. @Torey, what do you think?

I don’t really recommend animal compost from the store unless that is all you have, but if you don’t have a way to make it yourself then perhaps find a local farmer, or get some angora rabbits for their poop, which is a cold compost (okay, any bunny has great cold manure, I just love brushing the hair from my angoras and keeping the wool — and they are dual purpose, @Marjory Wildcraft , just not living in a bunny paradise like at your house).

We have a city CSA that will pick up compost from your home and compost it, quite genius I think. Although you have to sift it as children (and people who don’t know what to compost) will get plastic and stuff in there that doesn’t compost.

I think the largest problem with square foot gardening with a bottom is that once the roots hit the bottom the plant goes into survival mode and starts making seeds for the next generation, which could ruin your harvest. So while you can do a lot with container gardening, keep that in mind.

Make sure your containers are strong enough. Funny story (well, we are talking two weeks ago, and it wasn’t funny at the time), I bought 20 large totes, and my beautiful farmer friends filled up a yard of vegetables compost and stacked them on the side of the garage. Right. Where I rent. I thought I had health issues (turned out to be bad advice from Western medicine, but I digress), so I was not getting to the bins, including not poking holes in the bottom of the bins……. It rained, and the bins basically fell apart, compost and mud everywhere. I rent, and had to do a huge project removing everything outside, everything inside the home (like my food storage), and it was my birthday, but it all turned out well (except the therapy bills, no, just kidding ;)

So my advice is to purchase the wood, or simple plastic totes, or whatever you decide to use, but put holes in the bins or whatever medium BEFORE filling with the compost, soil, etc.

Can you garden in 100% vegetable compost? I had to donate all of mine to the community garden, and I would like another yard delivered once I have some sort of movable structure in place. Anyone have a good blueprint of a square foot raised bed? I’m still trying to get the thing behind the garage over dirt, but this may not happen.

—Christina

Torey

@heirlooms777 I've never used coir. Its less common here. So I'm not sure how much to add to a soil mix. I've never looked at the price so I don't know the economics of using coir vs other products.

Sorry about the mess you had!

If anyone is using vermiculite, make sure its not an old product that was laying around in someone's shed. Until the 90's, some vermiculite produced was contaminated with asbestos. In particular, one brand called Zonolite.

heirlooms777

@Torey thank you

heirlooms777

about coconut coir:

-substrate flushing: pretreat with 1 gallon water to 1 tablespoon of horticulture grade epson salt.

-test if your pH is fluctuating, simple liquid test strips are in expensive and work well, if you wanted to you could also get soil tests

-Christina