Galvanized Garden Beds

[Chelle P]

Hello. I live 9 hours north of the Canadian/US boarder in the heart of Canada on the MB side of the MB/SK boarder. My first time posting! You’ve probably been asked this a dozen times. I have 3 or 4 very large galvanized culverts varying 3-5’ diameter (originally meant for culverts under roads) on my hands! Yay! I want to cut them into pieces and lay them on their sides for raised galvanized beds which I would like to use for vegetable/fruit/flowers. Need to know: Are they safe to use for edible crops? If yes, what height do you suggest I cut them at? I am an able-bodied gardener with no mobility issues. I don’t want to make a mistake with this because it’s a lot of work to cut them. I have a good idea how to make the raw cut edge user friendly, but would love to hear your suggestions. Also, most important; how would you suggest I cut them? Blade? Disk? Welder? We have a ton of snow right now so it would be a good time to do this. Any suggestions would be welcome. Thank you

 

[Chelle P]

Hello. I live 9 hours north of the Canadian/US border in the heart of Canada on the MB side of the MB/SK border. My first time posting! You’ve probably been asked this a dozen times. I have 3 or 4 very large galvanized culverts varying 3-5’ in diameter (originally meant for culverts under roads) on my hands! Yay! I want to cut them into pieces and lay them on their sides for raised galvanized beds which I would like to use for vegetable/fruit/flowers. Need to know: Are they safe to use for edible crops? If yes, what height do you suggest I cut them at? I am an able-bodied gardener with no mobility issues. I don’t want to make a mistake with this because it’s a lot of work to cut them. I have a good idea how to make the raw cut edge user friendly, but would love to hear your suggestions. Also, most important; how would you suggest I cut them? Blade? Disk? Welder? We have a ton of snow right now so it would be a good time to do this. Any suggestions would be welcome. Thank you

 

[Mandy Onderwater]

Welcome to the forum @Chelle P

Oof. Uh, I'm no expert on this, though I'm always cautious with usuing metals in my beds that weren't made for it. I hope @JoshW could shed some light on this.
I also recommend checking out his thread, as he made (some of) his own raised beds!

My raised bed adventure - Hugelkultur inspired - Self Sufficient Culture

With the arrival of my 2nd child last Tuesday, I've got some time to get some jobs ticked off. I needed to repair a cracked pipe and put in a retaining wall to stop my yard flooding during the heavy winter rains but my local council won't let me put it close enough to the fence...

www.selfsufficientculture.com

 

[Chelle P]

Thank you . Will josh see my post? I have no clue how this works yet… I checked out the thread but there is no mention of galvanized steel culvert and safety.

 

[Mandy Onderwater]

By tagging him with @JoshW it should pop up in his 'Alerts', which is the bell icon in the top right. It'll show you that people have tagged you, reacted to you, answered in a post you follow, etc.

Josh will likely see your post, we will just have to wait until he comes online. Most people on here are working people, so understandably they aren't on here every day. Hope you can be patient (and that Josh is happy to share what he knows - and has the time).

I know galvanised steel raised beds exist, but I'm unsure wether they are coated with something that may make them food-grade... if that's even needed to begin with. I'm entirely unsure to be honest.
Maybe @DThille knows too, but he's a little less active as work, property management and studies are taking a toll on his free time.
@Lunai any luck? I know you've been working on and designing your own garden

 

[Chelle P]

By tagging him with @JoshW it should pop up in his 'Alerts', which is the bell icon in the top right. It'll show you that people have tagged you, reacted to you, answered in a post you follow, etc.

Josh will likely see your post, we will just have to wait until he comes online. Most people on here are working people, so understandably they aren't on here every day. Hope you can be patient (and that Josh is happy to share what he knows - and has the time).

I know galvanised steel raised beds exist, but I'm unsure wether they are coated with something that may make them food-grade... if that's even needed to begin with. I'm entirely unsure to be honest.
Maybe @DThille knows too, but he's a little less active as work, property management and studies are taking a toll on his free time.
@Lunai any luck? I know you've been working on and designing your own garden

Thank you . Much appreciated. It’s very late here where I am and i don’t know where any of you are located, so time zones are unknown. It’s ok. I’ll check back in the morning. I have tried to do research of my own on this. Opinions vary. I want to be absolutely sure before I spend time on this project. I haven’t got much to spare as our planting season is short. I sure don’t want to discover that this is unsafe after spending hours days weeks on it!

 

[JoshW]

Hello. I live 9 hours north of the Canadian/US boarder in the heart of Canada on the MB side of the MB/SK boarder. My first time posting! You’ve probably been asked this a dozen times. I have 3 or 4 very large galvanized culverts varying 3-5’ diameter (originally meant for culverts under roads) on my hands! Yay! I want to cut them into pieces and lay them on their sides for raised galvanized beds which I would like to use for vegetable/fruit/flowers. Need to know: Are they safe to use for edible crops? If yes, what height do you suggest I cut them at? I am an able-bodied gardener with no mobility issues. I don’t want to make a mistake with this because it’s a lot of work to cut them. I have a good idea how to make the raw cut edge user friendly, but would love to hear your suggestions. Also, most important; how would you suggest I cut them? Blade? Disk? Welder? We have a ton of snow right now so it would be a good time to do this. Any suggestions would be welcome. Thank you

Hi @Chelle P, welcome.

I did extensive research and found galvanised steel is perfectly safe to use for edible crops (including root crops). Zinc etc that makes up the coating van be found in nature (and our foods) after all. The only thing to look out for is using acidic soils and fertilisers, as this can break down the galvanised coating and lead to premature degradation of the steel.

I would cut using an angle grinder. Use a 1mm cutting blade - use a medium to expensive one. Cheap discs are a false economy! To protect the edge, you can get rubber U channel specifically for steel lips, or you can go the slightly more diy version of cutting an old garden hose - the channel while more expensive looks much nicer but sometimes you gotta work with what you have .

As for height - I love my high beds @ around 80cm. I don't love filling them, but the extra height means I can garden without pain. Minimum height I would go is 50cm. I have back and knee injuries so accessible gardening long term, is worth the short term pain of filling the buggers up. Your beds, being a circle shape, will be nice and stable at either of those heights.

Hope this helps

Note - do not use a welder to blow through or blowtorch or plasma cutter to cut these without proper ventilation and filtered breathing apparatus. The gal fumes are toxic! Fine cutting disc for the win, still recommended a mask (an N95 you've likely got laying around for covid is adequate - it's not going to be as hot as other methods)

 

[JoshW]

To add further - look at stock troughs and pre poly water tanks for human and stock consumption - all galvanised. Grain silos - all galvanised. Like I said, use that neutral soil and it'll be all apples. We specifically grow our acid lovers like blueberries in pots to avoid using acidic soil in our gal beds. Epic gardening had a blog on gal beds as well, if I get some time I'll get a link.

Here we go - https://www.epicgardening.com/galvanized-steel-garden-beds-safe/

 

[Mandy Onderwater]

Everyone lives in different countries and thusly timezones @Chelle P . Me personally, I live in Australia and at the time of this message it's around 6:30pm. Thankfully the forum stays up 24/7, so people can access the forum at all times of the day. It just means you might not get an immediate response as people can be asleep, depending on the time zone. I do try to be dilligent and pop on here multiple times a day, just to let people know "hey, we've seen it, please be patient while we get an answer back to you"

Thank you @JoshW . Very informative - I learned from it too! Cheers.

 

[Chelle P]

Hi @Chelle P, welcome.

I did extensive research and found galvanised steel is perfectly safe to use for edible crops (including root crops). Zinc etc that makes up the coating van be found in nature (and our foods) after all. The only thing to look out for is using acidic soils and fertilisers, as this can break down the galvanised coating and lead to premature degradation of the steel.

I would cut using an angle grinder. Use a 1mm cutting blade - use a medium to expensive one. Cheap discs are a false economy! To protect the edge, you can get rubber U channel specifically for steel lips, or you can go the slightly more diy version of cutting an old garden hose - the channel while more expensive looks much nicer but sometimes you gotta work with what you have .

As for height - I love my high beds @ around 80cm. I don't love filling them, but the extra height means I can garden without pain. Minimum height I would go is 50cm. I have back and knee injuries so accessible gardening long term, is worth the short term pain of filling the buggers up. Your beds, being a circle shape, will be nice and stable at either of those heights.

Hope this helps

Note - do not use a welder to blow through or blowtorch or plasma cutter to cut these without proper ventilation and filtered breathing apparatus. The gal fumes are toxic! Fine cutting disc for the win, still recommended a mask (an N95 you've likely got laying around for covid is adequate - it's not going to be as hot as other methods)

Thanks very much for all the info. This is terrific! I am going to proceed with my plans for amazing galvanized garden beds. I can’t wait for summer! Minimum distance to a city for me is a 6-8 hour drive. Going to go and buy a whack of cutting disks and permanent black markers to draw measured circles around the culverts. Your idea of the u-channel was exactly what I had in mind. Home Depot should have everything that I’ll need. Do you think I should use adhesive to permanently stick it onto the edge? Might be a good idea. I like your height suggestion and agree. I only want to do this once. Do you put anything into the bottom of your beds to take up space instead of filling with garden mix? I’ve watched a lot of videos. Not sure about this either. We have lots of different types of wood available here. I live in the middle of nowhere, forest and lakes everywhere. Definitely will wear a high quality mask/respirator. Thanks for thinking of it. For me it’s 3:33am right now. I’m a night hawk till spring comes because it’s dark in the winter. Then in March-April I get serious . I’ll post my progress. For now I’ll have to dig the culverts out of the snow and get cutting. We have about three feet of the stuff at the moment with more on the way. Thanks for your help.

 

[Mandy Onderwater]

You do not "need" to fill out the bottom of the beds. It's more that it can be cheaper to do it that way. Do keep in mind that wood breaks down over time, so you may experience some sinkage in your beds, so they might need a good top up later down the line.

Here you'll see a very young Mark, 5 whole years younger, talking about how he filled his raised beds Hugelkultur style.


In this video that's only two years old you will see some pictures you will have seen in the former video. These also show his opinions and how it went.


In this video you will see him put in a raised bed, with some handy tips (sadly prongs are no longer available). You can see him fill the bed and the handy tips along the way are lovely as well.


If you are familiar with Birdies raised beds, you may know they have support 'rods' so ensure that the raised beds don't bow out. However, as Mark has found, because he's filling the bed in such a "dirt cheap way", the sinkage may cause some mild issues (though thankfully, easy to fix).

How to FIX and STOP a Raised Garden Bed From Caving Inwards

Top tip! Want to talk to Mark directly? Did you know that there is another way, outside the forum? Support Mark on Patreon: https://www.patreon.com/selfsufficientme (the top tier $25 AU enables mentoring from Mark via an exclusive VIP email where he will answer your questions etc ASAP).

www.selfsufficientculture.com

 

[Lunai]

Hi @Chelle P
Welcome to the forum!
I totally agree with Josh on the galvanized steel stuff. Food safe but be carefull with acidic stuff.

as for the filling: you can pretty much throw everything in them that is compostable. However, if you don't fill them with earth the whole way up, you will have sinkage, about 20cm in 5 months at the start. I had that in my oldest new raised bed. I put a lot of green cuttings and stuff from our shrubbery in at the bottom and all the old tomato plants and leaves and grass cuttings. And over the last months it has sunken considerably. But I don't mind. I just put 2 120L bags full of autumn leaves back in, and now it's filled up nicely again. Big plus to this kind of filling: It produces heat, wich in our region with getting snow and stuff can extend the growing season. And you have premium compost right in it from the start, and won't have to use fertilizer in the first 1-2 years at all. It really creates a healthy soil. third big plus for me: you can get rid of some bigger stuff (branches etc.) that are usually too big for the normal compost bin without having to throw it away. (In germany we would have to pay so bring large branches or stuff to the waste disposal site, wich you have to do if you can't use the stuff somehow...)

I hear you Most active people here on the forum are from Australia and the American continents, so me being in germany I always have to wait a little bit on a reply. Because the Aussies are already asleep and the others are still asleep Besides @Mandy Onderwater... she's a special one you could think she almost never sleeps

 

[JoshW]

Thanks very much for all the info. This is terrific! I am going to proceed with my plans for amazing galvanized garden beds. I can’t wait for summer! Minimum distance to a city for me is a 6-8 hour drive. Going to go and buy a whack of cutting disks and permanent black markers to draw measured circles around the culverts. Your idea of the u-channel was exactly what I had in mind. Home Depot should have everything that I’ll need. Do you think I should use adhesive to permanently stick it onto the edge? Might be a good idea. I like your height suggestion and agree. I only want to do this once. Do you put anything into the bottom of your beds to take up space instead of filling with garden mix? I’ve watched a lot of videos. Not sure about this either. We have lots of different types of wood available here. I live in the middle of nowhere, forest and lakes everywhere. Definitely will wear a high quality mask/respirator. Thanks for thinking of it. For me it’s 3:33am right now. I’m a night hawk till spring comes because it’s dark in the winter. Then in March-April I get serious . I’ll post my progress. For now I’ll have to dig the culverts out of the snow and get cutting. We have about three feet of the stuff at the moment with more on the way. Thanks for your help.

No need for adhesive, it's made to just grip itself. It might come loose as it gets old (take years of sun exposure) but it will be 10x better to replace than scraping glue when it degrades.

As for filling, I usually go 2/3rds of cheap mulch - I don't have access to wood or I'd use that. The mulch breaks down into soil eventually. I top up beds with compost as they sink, so you get a chance to build a great soil - so many worms! Also, if you flick through my thread Mandy so kindly linked, you'll see I've even filled one with approx 1.6t of concrete!

 

[DThille]

Welcome. So you must be up somewhere Thompson way. I haven't been up there in many years.

I got our raised beds (galvanized) from Raised Garden Beds Canada - that's just a Shopify site. Anyway, I went with 36" and I regret going that high. Something like a table height is probably reasonable. There's a thread on here of our assembly and filling of the beds. Raised Garden Beds inspired by Mark

Good luck!

 

[Saskatoon mike]

I'm in Saskatoon nice to other Canadians here. My raised garden is made of wood and I made them waist high. For our height it works great not much strain on the back

 

[DThille]

I grew up in Rosthern and earned 3 degrees at the U of S (and don't use any of them directly now, but that's a tale for a pub).

 

[Saskatoon mike]

Soil do you test it for acidity. This whole gardening is very new to us. Mark from self sufficient me from Australia has put us on the right path but it's the climate and grow season that mixes us up. He grows vegetables at different times so we have to just .... wing it. We believe (hope) if someone can tell us if we need to test the soil for various vegetables and strawberries. We found out that tomatoes grow very well in mulch we got from the city of Saskatoon at the end of 11th street for free to help fill the raised gardens with logs, branches, cardboard leaves on the bottom. Very interested in your thought

 

[Mandy Onderwater]

Yes, testing your soils PH can be an amazing tool to see what will grow well there - or what amendmends need to be make.

 

[DThille]

I've heard from the Gardening at USask folks that the City of Saskatoon compost is dry (hygroscopic? hydroscopic?) and needs to be soaked quite thoroughly before it will absorb water and do its desired work in the garden.

Native soils on the Canadian prairies tend toward alkaline or basic. Most annual vegetables want a fairly balanced soil. Some shrubs, like blueberries, prefer more acidic soils. Of course, wild blueberries grow in the boreal forest among the pines and peat which is more acidic in the first place.

That said, I've never had any testing done. There are some basic test kits you can purchase from a garden centre that will allow you to test it yourself. For a gardener looking to produce something for themselves, that should be good enough. Full soil testing, while it can provide very interesting results and help you to make better decisions about amendments can be quite expensive so unless you are running a business based on your soil, I'm not sure it's worth it. Also, if you don't intend to fertilize to the deficiencies, then it doesn't necessarily give you anything you are going to apply.

So, I'd say it certainly doesn't hurt, but may not provide a lot of value from an economic perspective.