Got Raised Bed Gardening Questions?
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{ 66 comments… read them below or add one }
How do I calculate the amount of soil I will need to fill my raised bed?
Great question!
I have two resources for you that help you calculate how much soil you will need for your raised bed, depending on size of the bed and the depth that you want.
http://www.plantanswers.com/garden_column/jan_03/4.htm
http://www.gardenplace.com/content/calculator/mulch_calc.html You can use this calculator to calculate each 4 inches worth of soil, and add it to together that way.
how do I calculate how mush topsoil I need in my flower beds?
@Joe
Here’s a good online calculator. Just plug in the size, and depth that you want, and it will tell you how much soil in cubic feet.
http://www.garden-ville.com/4376808_36600.htm
I live in Florida and just finished building a raised bed for the kids. The plan is to grow easy vegetables (we have not figured out what yet) but I am now stumped as to what kind of dirt/fill to use. Again, we live in Florida so it will be pretty warm and sunny most of the year. The bed is about 3′ by 6′. Any suggestions?
I highly recommend using the Square Foot Gardening soil recipe to fill your raised bed, even if you don’t use the rest of the method for planning and planting your garden. That soil recipe practically guarantees gardening success.
http://www.mysquarefootgarden.net/mels-mix/
I also recommend the Square Foot Gardening book, which you can buy at Amazon or at any bookstore in the gardening section.
I am planning on growing climbing roses, however is a raised bed garden able to properly support them? And exactly how would you situate a trellis in relation to the raised bed?
Thanks for your question.
Yes, you can certainly grow climbing roses in a raised bed.
You could handle it many different ways. If you were going to put the trellis up against a wall or fence, you could create a three sided raised bed, against the wall. Or, you could build a four sided raised bed and put a trellis on the outside of one of the four sides. Just make sure that your trellis is sturdy and installed well, and you’ll be fine.
If anyone else out there has already done this, please feel free to chime in with more details about what you did.
Is it possible to build a raised bed garden (flowers) on top of a concrete slab? I live in Northern Ontario. On side of the garden will be bordered with tall pine trees. What do you think?
Great question!
I have not tried this myself, so I did a little bit of searching for you and here’s what I found.
Yes, you can do it.
Here’s a great Gardenweb thread about it.
http://forums.gardenweb.com/forums/load/smallspaces/msg082156141678.html
And here’s an entire book about the subject, on Amazon.
http://www.amazon.com/Gardening-Pavement-Tables-Hard-Surfaces/dp/0881928127/
Please come back and tell us how you did!
Is there any advantage/disadvantage from using either bricks
or concrete blocks to make a box for raised bed?
@Sharad.P.,
Thanks for your question.
From a gardening perspective, I don’t think there’s any difference. Both are safe to build a raised bed garden with.
I think mostly it’s a question of which one is easier for you to work with, and which one you prefer the look of.
Last year slugs completely ruined my flowers, plants & vegetable gardens; I used beer traps, etc. I just could not keep up with them. Every day there was enough to make a stew for hundreds! Do raised beds help with this problem?
@Karen,
No, a raised bed won’t make a difference per se. A slug can just as easily climb up the side.
Last year was a really wet year in many parts of the country, so perhaps the slug onslaught was related to that.
Here are some products you might consider:
http://www.cleanairgardening.com/organic-slug-bait.html
http://www.cleanairgardening.com/slugsaway.html
Eggshells around your plants are also a recommended option.
http://www.thegardenhelper.com/slugs.html
Is it a good idea to cover (tarp) a raised bed after the growing season to preserve soil nutrition? This question refers to a raised bed that wouldn’t be covered with mulch or a cover crop.
@Keith Brace,
Good question!
I’d lean toward adding more organic materials or compost at the end of the season and tilling or spading it in, and then giving it all winter to make sure it’s completely broken down.
Or, you could do something like a lasagna gardening or trench composting kind of approach where you add a lot of materials that have not broken down yet, and let them finish over the winter.
I personally did not grow a cover crop, and also didn’t cover my own raised bed garden over the winter. I did add some more organic materials to my raised bed though, which gave it all winter to break down.
Here’s another good page that isn’t specifically about raised bed gardening, but covers getting ready for winter. He does mention using a tarp as an option.
http://www.helium.com/items/555030-how-to-prepare-your-garden-for-winter
Hi-
What is your suggestion on the life of soil for raised beds?
I have 9 cedar raised beds for vegetables that took about 12 yards of mushroom mulch to top off .
This is my 3rd growing season in the beds. I rotate my vegetables and add compost. I have also added a few dozen night-crawlers to each bed.
The beds are full of worms (lots of small ones – so they arrived on their own, or are hatched from the ones I added).
The soil is still rich and dark…
What is the best way to keep the soil fertile?
I have heard that over time the soil will start to produce less vegetable. Will I be required to dig out 9 beds (12yards of soil) and add new soil?
db
with a raised bed do different veg need differant depths like tomatoes, peppers, lettece, green beans
@Michael,
If you have at least 8 inches of soil, you should do fine with just about any vegetable.
My problem is I already have an established garden, that has settled and “sank”.. I want to raise the whole bed, with a short decorative wall bordering it. I don’t think it needs to come up more than a foot or so. I guess my question is- can I dump dirt all around, and even over some of the existing flowers, and will they grow up through it okay? or should I uproot everything and start over? Thanks!
@Danette Lykins,
Your best bet would be to start over at the beginning of the season, before everything has started to grow.
If you put in a lot more soil now, it’s likely that you’ll end up harming your existing flowers because they’ll be buried too deep.
I’ve just built two large raised beds used existing soil plus some added top soil ,multipurpose compost and manure.Is this the right mixture for these? I am a novice gardener and don’t know what to plant in these beds.Any ideas?
@marie,
Sure, that sounds like a reasonable soil recipe.
The manure is all well aged, I hope. If manure is too fresh, it can burn plants.
You can really grow anything in a raised bed from flowers to vegetables. So it depends on what you’re looking for in a garden.
If you’re going for vegetables, I always recommend growing what you usually buy at the grocery store. Because then you know you’ll really use it!
Last weekend I planted my first garden ever and it is a raised bed planted with vegetables. I have been watering once each day and am now seeing LOTS of ants. Should I put something in it to get rid of these or will they even hurt my plants?
@Tricia,
I wouldn’t worry about the ants. I don’t think they will hurt your vegetable garden.
If it appears that they are crawling all over any of the plants and the plants are suffering as a result, a Spinosad based organic spray will take care of them safely.
Hi, I am almost ready to build raised bed. What should I use to
prevent weeds from entering my raised bed from four sides and the bottom. I am not worried much about the bottom because
my soil is good and I cleaned it too. I went to Home Depot,Costco
etc and all of them says made out of recycled material and use for
flower garden,retaining wall etc but they don’t say vegetable garden. Are those ok to use in vege. garden? if not what should I
use? Any suggestion.
Thank you.
Sharad.P.
@Sharad.P.,
All of the landscaping weed block fabric is safe for vegetable gardening as far as I know. It’s just a thick fabric, and it isn’t treated with any chemicals that I am aware of. I used it at the bottom of my own raised bed vegetable garden!
If you’re worried, you can always use several layers of wet cardboard as your weed block. Or even more layers of wet newspaper.
@lars, Thank you Lars,this will help me because there is a sell at costco
for big roll and now I can use that.
Sharad .
Old carpeting works well, too.
I am getting started on my first raised-bed garden. Someone told me that you can attach plywood to the bottom and then fill your box with your soil. Is this an option?
Andrea
@Andrea,
No, not really.
Are you building a raised bed that’s on legs and lifted off the ground? Or are you putting it directly on the ground?
If you were trying to build a box on legs, then you could maybe put plywood at the bottom to hold the soil. But you’d want to drill a lot of holes in it, so that it could drain.
If it’s directly on the ground, you don’t want to put plywood on the bottom, because your raised bed won’t drain.
If you want to block any weeds from growing up from the bottom, just use several layers of wet cardboard, or thick layers of wet newspaper, or landscaping fabric. All of those will allow water to drain out, but will block weeds from growing up.
Hello!
So, I know this is not the best scenario but I’m building a raised vegetable garden out of scraps my boyfriend had used for a fence. The problem is it’s weather-treated wood. He bought it recently so it shouldn’t be the CCA kind. Can I still garden happily? I know people recommend a plastic barrier but I haven’t found any specifics. Any recommendations?
Thanks!
———-
Well, it’s great you are recycling! If the lumber was bought recently, could you check with the store where it was bought and confirm exactly how the lumber was treated? Yes, a plastic barrier can be used between the soil and lumber. Here’s more information on construction materials for raised gardening beds.
Hello,
I find your site very interesting !!!
I have a question about the lining in my raised bed on legs.
The bottom of the bed is made of hard wood planks 6″ wide by 3″ thick , with 0.5″ space between, to allow for drainage. my question is : should I cover the wood at the botom with : A) a plastic sheet ? B) paper barier like we use under the shingles on a roof ? C) or the landscaping fabric ? Of course for the A and B , I would make many holes to allow water to drain.
Thank you very much for your advise.
do plants particularly tomato plants require less or more watering in a raised bed? thanks for your reply
@debbie
I’d have to say that it depends on which soil you are using to fill up the bed, and how good or bad the soil is in the ground nearby.
I use the Square Foot Gardening soil recipe for my raised beds, and it’s almost impossible to overwater with that setup. It does not dry out quicker though. So I’d say that I don’t have to water more often, but it wouldn’t hurt if I did in my situation.
It isn’t like container gardening, where the containers definitely require more watering in hot weather and tend to dry out.
I’d treat it mostly like a traditional garden in the ground.
We have a lot of slugs in our garden. We are building a raised bed and heard that lining the bottom with window screening is a good idea. I purchased fiberglass screening and now I am wondering if it will leech any chemicals harmful to vegetables, which is what we intend to grow in the bed.
@Anne
I personally would not worry much about it. There are plenty of fiberglass planters out there on the market, so I don’t see how the screening would be a very big deal.
Hello – Is it necessary to remove grass before filling a raised bed with soil? Would it be OK to just cover it first with landscape fabric?
Thanks!
@Melissa
You can just cover it with landscape fabric, but the grass might figure out how to poke through. Particularly if it’s some kind of aggressive grass like Bermuda. You’d get the best results by taking a little bit of extra time and digging up the grass first.
Ok, so I did take the extra time to remove Bermuda grass before filling my raised bed garden. I also put down landscape fabric. Guess what? Bermuda grass is back! Now what? How do I rid my garden of the Bermuda grass? Also, my garden is about 10 feet away from redwood trees and their roots have invaded. Any suggestions would be appreciated. Thanks.
I live in the Southern Outerbanks of North Carolina. I have a 4′x12′ raised bed. This is my first year for gardening. We have a fairly mild winter here and I want to use a removable plastic cover over my veggies on those rare occasions it drops below 40 and we get frost. I have purchased what was discribed as CLEAR PLASTIC SHEETING in a 3mil thickness, like what you cover windows with. Is this a good item to use? Do you think it is opaiq (sp) enough? I have added gromets to make it easier to remove and reinstall.
I’m wondering if you suggest covering my raised beds over the winter. If so, with what? My main objective is to avoid weed seeds which will germinate in the spring.
I have read here and elsewhere that raised bed gardens can produce more vegetables than a traditional garden. How does that work exactly? Can you plant closer together? I planted according to the directions on the seeds and plants I purchases (24″ spacing), but quite frankly my garden looks bare. Also, I understand some vegetables do particularly well when planted together, but haven’t found specifics.
I have a slopped side of my yard that I would like a raised bed veggie garden installed. Do you have any suggestions?
Hi, what a great site you have!
I’m planning to build a raised garden that will NOT be sitting on the ground. I want to use marine grade plywood. I know I need to drill lots of holes for drainage. My question is: Do I need to put landscape fabric between the plywood and soil?
@Amy
Yes, I would use landscape fabric. It will hold the soil in better, and will also slow down the degradation of the wood.
I am planning on building a bed this year, however my yard has a pitch to it. Is it ok to build the raised bed on an angle? It’s not extremely steep, but it is definitely pitched.
Jeff! Hi it’s Em! from ob7:) i was reading the posts and recognized ur pic! I actually just built a 6′ by 12′ raised bed on an area of my yard where theres a slight pitch and it worked out fine! I used posts (4×4′s) in each corner and the two posts at the lower level are taller so the beds level. you understand what i mean? im not explaining it correctly but anyway, a small pitch wont make a difference! We have to talk gardens soon!!! see you!
Hello. I’m planning my raised bed area next to my wood shed. The frame is treated, but new. Would it be affecting my garden soil if it’s a raised bed? Thanks for your time
well, I just built a large raised- bed in my yard, and my husband and I are just about ready for the dump truck to deliever a load of topsoil to fill it. (we live in an area along side mutiple creeks, so the normal soil is just clay) We are wondering if we have to do anything to the dirt and grass on the ground before we dump in the dirt, and, do we have to mix anything in with the topsoil before we start growing?
My son built a raised bed for me last year that performed well, but it was made from old treated lumber. I am health conscious and wondered if this is going to make a difference on the quality of my vegetables. My husband suggested lining it with plastic. Is there anything I should do?
I have a lot of gophers moved in my yard, I’m thinking of building a raised garden. Should I use chicken wire or plywood at the bottom my raised garden for protection from gophers. Please advise. Thanks
For Jeff,
I live in the north of the UK and for years I passed a lovely little home which had a south facing garden on a precipitous slope. It was very productive. I always wondered about the fact that it was beside the M6 Motorway though! All those fumes…
If you can keep the soil in the raised bed and your bed isn’t in a frost pocket, you should be fine. If it slopes to the south you should be laughing!
L
I had planned on planting Stargazer lilies this year, then i decided on a raised bed, and decided they would be too tall for that. So i am planting them next to my garage where there is abundant sunshine. My question is, what would be best grown in a raised bed? My yard gets 6-7hrs+ of sunshine daily from morning til afternoon. Im just unsure of what to plant that will look nice by my new patio. My bed will be 2ft tall, 2ft wide, and 6-7ft long, sitting on the ground. thanks!
I am just startng my first raised garden beds which I plan to place in my back yard. My question is, do I have to dig up the grass or will the soil I put in the box take care of everything.
@barbara
Your best bet is to put several layers of newspaper or cardboard at the bottom, or landscaping fabric. And then put the soil on top of that.
Some types of grass will be able to grow right up through the soil, even if it is pretty deep. Bermuda, for example, is highly invasive.
I am a renter and we have very little area thats already designated for gardening. We have yard area but our landlords don’t want us tearing up the grass to make more flower beds. Do raised gardens harm the grass thats underneath?
@Alicia,
Yes, it will kill the grass underneath when you put in a raised bed.
I’d recommend putting the raised bed on top of the area where it’s already designated for gardening, and then use the Square Foot Gardening method to get a much bigger yield from a smaller space. I only have a small 6 x 8 raised bed garden at my house, and I can still get a lot of vegetables. The Square Foot Gardening book is available at any bookstore. They also have a web site, which gives you some basic information.
I have purchased a DIY raised garden bed kit. I will be placing my garden bed on pavement in the backyard.
Q: What do I put under the soil? Do I need to put anything on top of the concrete, but under the soil? HELP!
@Marla
Good question! I haven’t actually tried putting a raised bed on top of cement, so I didn’t have a good answer.
I found this message board thread that shows that other people are doing it, and having success. They are all using slightly varying methods, so I’ll just give you the link. Good luck!
http://www.helpfulgardener.com/phpBB2/viewtopic.php?t=19322
Will strawberries do well in a raised bed? I live in southern Wisconsin, zone 5, and I tried once to put daffodils in a raised bed, only to discover that they don’t do well in a raised bed, none grew the following spring. How will strawberries do, will they survive the winter? Or should I plan to put them directly in the ground?
@Debi
In general, strawberries do very well in raised beds. It is often a recommended way to grow them.
http://www.diynetwork.com/outdoors/tips-for-growing-strawberries/index.html
http://www.farmfreshliving.com/How_to_Grow_Strawberries.html
I want to build a gaden bed by a concrete wall i have in my yard. Do I need to build the box with 4 sides or would just having the front and 2 sides enough since the concrete wall it’s against can act as the back side?
@Sarah
Yes, it should be fine, as long as the other 3 sides are going to be set up in a way where they won’t slide away from the wall or come unattached, letting soil come out.
I am almost ready to give up! 3 years ago I built 2 containers for a vegetable garden. My garden starts off beautifully…thrives until about waist high and other plants are looking healthy and ready to produce, then everything begins to wither and die with very little yield. 3 years in a row the exact senario. I have black walnut trees in the yard, and local nurseries think this may be the culprit. I am thinking of digging up the boxes and lining with landscape fabric today, because I did not do that when I built the boxes. It will be a lot of work. Do you think it is worth it?
I have had raised beds for three years here in France but with limited success as they are always plagued with mice. This is presumably
because the raised soil is accessible and soft. Has anyone else had
this problem and is there a solution, otherwise I will have to remove them and go back on the flat.