seedsowing
Newly Registered
Posts: 7
Joined: Fri Oct 28, 2011 12:37 pm
Location: Lubbock, TX

dilemma over raised bed construction

I am establishing a new vegetable garden in an area that has some bermuda grass. I plan to lay landscape fabric at the bottom to prevent grass and weeds from growing up in the beds. I've seem to have two options: either construct cedar plank raised beds and place directly on top OR secure the beds with 4x4's burried in each corner. With burried posts would be more permanent, but I fear creating a hole in the landscape fabric would allow unwanted grass to poke through. What do you suggest? :roll:
Seed Sowing in Lubbock

SOB
Green Thumb
Posts: 311
Joined: Mon May 31, 2010 6:44 pm
Location: Radnor, OH

What are the dimensions and depth of the bed going to be? I think that if your bed will be at least 6inches deep you don't have to worry about grass/weeds growing up through it.

As for the supports, keep in mind that there will be quite a bit of dirt inside meaning that the dirt will try to push out from the middle causing the sides to potentially bow. In mine I placed 1"x1" stakes about 1.5 feet in the ground in the corners and every 3 feet or so and screwed them to the sides of the bed.

User avatar
applestar
Mod
Posts: 27798
Joined: Thu May 01, 2008 11:21 pm
Location: Zone 6, NJ (3/M)4/E ~ 10/M

Landscape fabric is not always the best solution.

I think in this case, (optional) edging to prevent new incursion and cardboard in the bottom to smother the existing grass may be a better option. The cardboard will breakdown (and invite earthworms) later in about 3 months so the vegetable roots will be able to grow DOWN into the underlying soil.

Typically, this is done in fall so you can plant in spring, but it's also possible to plant shallow-rooted plants earlier on or to plant vegetables that will develop deeper roots later on.

Cardboard and heavily mulching the surrounding area/paths will take care of the rest.

gumbo2176
Super Green Thumb
Posts: 3065
Joined: Mon Jul 19, 2010 6:01 am
Location: New Orleans

applestar wrote:Landscape fabric is not always the best solution.
I think in this case, edging to prevent new incursion and cardboard to smother the existing grass may be a better option.
That's exactly what I thought when I built my 4'x12'x1' deep raised bed. I dug the area where it was to be placed, removed all the grass I could put my hands on, placed the box, laid 2 layers of heavy cardboard in the frame and filled with topsoil and compost. That was done in mid 2010.

I now have weeds growing in the form of Bermuda grass and an invasive vine we call "Bush Killer" that only needs the tiniest of stem or root to take off again. That stuff is our Kudzu.

That said, I'm not entirely sold on that weed blocker material either.

User avatar
applestar
Mod
Posts: 27798
Joined: Thu May 01, 2008 11:21 pm
Location: Zone 6, NJ (3/M)4/E ~ 10/M

Do you suppose the new Bermuda grass and kudzu were introduced with the topsoil and compost? Cynthia_h has written about her battle with Bermuda grass (I believe) and she said she sifted all the soil through hardware cloth. :shock:

cynthia_h
Super Green Thumb
Posts: 7501
Joined: Tue May 06, 2008 11:02 pm
Location: El Cerrito, CA

applestar wrote:Do you suppose the new Bermuda grass and kudzu were introduced with the topsoil and compost? Cynthia_h has written about her battle with Bermuda grass (I believe) and she said she sifted all the soil through hardware cloth. :shock:
https://www.helpfulgardener.com/forum/viewtopic.php?p=130376

Cynthia H.
Sunset Zone 17, USDA Zone 9

john gault
Green Thumb
Posts: 461
Joined: Sun Jul 10, 2011 8:53 pm
Location: Atlantic Beach, Fl. (USDA Hardiness Zone 9a)

I can't give you any real good advice, because I'm still battling with bermuda grass. But I think I'm starting to win. I basically just heavily mulched my garden (which is surrounded by bermuda grass on all sides) with a heavy layer of leaves and pull any grass I find poking up. In some areas it's more aggressive than others, so in those areas I lay down cardboard under the mulch. Basically if you want to keep this stuff away, without resorting to chemicals you must attack its achilles heel, which is shade -- it does not like shade. So if you see some coming up put some shade on it.

I think I've finally got control of the stuff, but really your fight is never over, just maintain a "steady strain" of weeding when out in your garden.

Tate
Cool Member
Posts: 62
Joined: Wed May 19, 2010 6:39 pm
Location: Houston

I build 5' x 10' beds that are 12 inches deep out of 3 - 2 x 10's (untreated) - one cut in half. I rotate the corners and use 2 - 3 1/2 deck screws in each corner. I never have a problem with bowing etc. I've never used any additional support. I buy the big rolls at Sam's of the weed fabric and lay underneath directly on any grass. I just make sure to mow it as low as I can first so it will lay more flat. In the beds where I have used this strategy - I have 11 of them - I have had no issue with invasive weeds. In the beds where I used cardboard or nothing, I got lots of weeds over time including nutsedge and bermuda grass. I am actually converting some of those beds next Spring to my so far full proof method with the weed fabric because I am tired of harvesting nutsedge and bermuda.

I also lay the fabric around my beds and put cheap mulch on top of it for my garden pathways. At the edge of the mulched area I have some landscape edging that frames the area nicely. This is also good because I am not mowing or weed-eating very close to the beds and stirring up any weed seeds or soil-borne pests that can invade them.

One more thing, I typically mulch with leaf mold compost. It suppresses weeds, amends the soil, adds beneficial microbes to your soil web and helps retain moisture. Luckily, I have an organic soil yard about 10 minutes from my house where I can get a yard for like $34. Any good compost will work though.



Good luck

Tate

User avatar
GardenRN
Greener Thumb
Posts: 1102
Joined: Wed Jan 12, 2011 3:01 pm
Location: Chesterfield, Va

Didn't have time tonight to read everyone's responses. But let me offer some advice gained through experience. My backyard is a bermuda grass FARM!...unfortunatley. Anyways, I have had weed paper down and the grass grew right through it. I did a quck scan of the other responses and my suggestion would be this. Build your raised beds and then fill the bottom with cardboard side to side. Then add mulch on top of that. Then have at least 12" of soil on top of that. It really needs to be smothered to kill it.

One thing I did find is if I got one of my tarps out and layed it on the grass and secured it down and left it there for about 2 weeks or so, especially if it was hot outside, it killed the current growth pretty good. So maybe lay a tarp down and have it kill the existing grass, and then build your planter box on top of that and add the cardboard and mulch and soil. All of that will be too much for new growth to push up through with no sunlight. Best of luck to you!

If you find out any tricks or anything let me know, I am always having trouble fighting mine every year.
Jeff

USDA Zone 7a, Sunset Zone 32.

Failure is only a fact when you give up.

User avatar
Tilde
Green Thumb
Posts: 344
Joined: Tue Sep 06, 2011 5:56 pm
Location: Hurry-Cane, Florida USDA10/SZ25

The grass came up through my boxes - despite lots of cardboard etc

I'd smother with cardboard past the boxes & around it. Next time I build, I'll do cardboard a foot out beyond the box & heavily mulch or cover it with something to use as a footpath.
USDA Zone 10, Sunset Zone 25, 16 feet above sea level, surrounded by chem-turfers.

seedsowing
Newly Registered
Posts: 7
Joined: Fri Oct 28, 2011 12:37 pm
Location: Lubbock, TX

Thank you

Thanks to all of you who have responded to my plea for help. Here's my plan. Till the area and remove as much of the bermuda roots as possible. Cover the entire area with weed-blocking landscape fabric. Roll the edges together and secure with landscape staples. Build the raised bed using 2x8 cedar. Join the corners with deck screws. Each box will be 8' x 4' and 16" high. As a precaution I'll add a 1/2" layer of newspaper at the bottom or perhaps cardboard at the bottom. Then I'll add a mixture of good soil & peat. My beds will be at least 2' apart. My plan to to add crushed rock in the pathways.

At some point I'll add a drip irrigatation system. Right now hand watering will be my best option.

I'll post picture of the progress on my website.

Thanks again - you've been GR8T! :lol:
Seed Sowing in Lubbock

cynthia_h
Super Green Thumb
Posts: 7501
Joined: Tue May 06, 2008 11:02 pm
Location: El Cerrito, CA

I would caution you that tilling will rejuvenate the roots/runners of the Bermuda grass. Each and every root "bit" can generate a new plant. That's one of the reasons I didn't use any mechanical assistance when I attacked the Bermuda grass in Berkeley.

I demarcated the area to be worked on each day by driving down with a sharp, square shovel and severing the roots. Then I started in with the "lifting and sifting" process.

I shudder to think how much more work it would have been with extra pieces of root thrown about....be careful in your selection of techniques.

Cynthia

seedsowing
Newly Registered
Posts: 7
Joined: Fri Oct 28, 2011 12:37 pm
Location: Lubbock, TX

I'll take heed

Cynthia - thanks for the warning. Maybe just laying the landscape fabric will be enough. Fighting bermuda grass is new to me - In Colorado I had blue grass and it was easier to control. I have found some really deep ugly roots when I tried to dig up some of the bermuda grass.

If I could just snap my fingers and make the unwanted grass grow in the lawn area I would be a happy camper. All summer I have been growing grass in little cups and then transplanting it when it is about an inch tall. It is a slow process but the grass is filling in nicely.

Thanks again - I'll take your warning to heart.
Seed Sowing in Lubbock

SOB
Green Thumb
Posts: 311
Joined: Mon May 31, 2010 6:44 pm
Location: Radnor, OH

What about pulling up the sod with a shovel and relocating? I have no experience with Bermuda Grass but I know when I made my first raised bed I pulled the sod and moved it and for the second all I did was turn the sod over. Either way I get very few weeds or grass with 12" of soil on top.

Maybe you're not into this but spray the area with round up to kill the grass. Then wait a while and plant? Just an idea...

User avatar
GardenRN
Greener Thumb
Posts: 1102
Joined: Wed Jan 12, 2011 3:01 pm
Location: Chesterfield, Va

cynthia_h wrote:I would caution you that tilling will rejuvenate the roots/runners of the Bermuda grass. Each and every root "bit" can generate a new plant.

Cynthia
I very much agree! I tilled and raked up roots till my hands hurt. Only to have it all grow back as soon as the warm weather was there. And through 5" of mulch! So disheartening :?

Good luck to you! If your beds are 16" deep maybe that will be deep enough that the grass wont be able to grow through it anyways. As others have stated, be sure not to let it creep in the sides. That stuff is so dang nasty. :evil:
Jeff

USDA Zone 7a, Sunset Zone 32.

Failure is only a fact when you give up.

lily51
Greener Thumb
Posts: 735
Joined: Mon Aug 02, 2010 6:40 am
Location: Ohio, Zone 5

These invasive and tough grasses are a challenge, defying most attempts to irradicate them from gardens. And digging just spreads them.
Many will not like this, but the only thing that has ever worked in a raised bed here is to sprayto kill it, then cover with your cardboard, mulch, soil. Make sure your beds are deep enough, at least 10".

Maybe a raised bed that is waist high would work to smother the plants with just cardboard and soil.

Picture the great prairies, with grasses that can go dormant and then spring to life, and then the eastern U.S. prairies with their 6' tall grasses. These plants are resiliant!

john gault
Green Thumb
Posts: 461
Joined: Sun Jul 10, 2011 8:53 pm
Location: Atlantic Beach, Fl. (USDA Hardiness Zone 9a)

I've yet to spray the stuff and I got it pretty well under control in my non-raisedbed garden. I'm 100% confident I would have no problems in a raised bed, especially if I can keep them at bay in a conventional garden.

However, I will concede that spraying would be the most effective way, i.e. non-physical labor way. However, I only tilled once (in the very beginning), which is the hardest part, but if I had to do it all again I wouldn't even do that, now that I know their number one weakness -- shade.

Granted without spraying my job will never be done, but it's very manageable. But I'm willing to bet that the person that sprays will also be amply employed in fighting bermuda grass. I just don't want to use that much spray. And there is a certain satisfaction I get by pulling the stuff out by the roots :twisted: It's actually pretty easy when the mulch is thick. However, on bare ground where the stuff is established I'm fully aware of how deep and entrenched them roots can be.

BTW, When one fights bermuda grass one must wonder if this is the ultimate life form on earth. :?

cynthia_h
Super Green Thumb
Posts: 7501
Joined: Tue May 06, 2008 11:02 pm
Location: El Cerrito, CA

john gault wrote:... And there is a certain satisfaction I get by pulling the stuff out by the roots :twisted: ... However, on bare ground where the stuff is established I'm fully aware of how deep and entrenched them roots can be.

BTW, When one fights bermuda grass one must wonder if this is the ultimate life form on earth. :?
1) When I eliminated the Bermuda grass from our "lawn" in Berkeley, I first uprooted as much as I could. Very satisfying, I agree! :twisted: Then I started the dig-and-sift process. Believe me: those roots were "deep and entrenched." I remember one in particular that was over 6 feet long. :shock:

2) Ultimate form of life on earth I think must be either cockroaches or sharks; opinions are divided. But both are ancient, from pre-Cretaceous times (I think?), whereas most mammals date from the post-Cretaceous/Tertiary boundary mammalian radiation, so we're pretty new on the block.

--Having lived in old buildings where roaches also live, I'd rather deal with Bermuda grass; at least it doesn't contaminate my food supply. :x

--Sharks...well, I've swum in the San Francisco Bay (warmest temps are in August, approx. 56* F, or 14* C), where it's too cold for most shark species. I only bumped into a shark once. I think we were both incredibly startled. When I got back to shore, other swimmers said it was probably a young [url=https://en.wikipedia.org/wiki/Leopard_shark]leopard shark[/url], harmless to people--except for sudden accelerations in heart rate and swimming speed! :D

Cynthia

User avatar
Gary350
Super Green Thumb
Posts: 4988
Joined: Mon Mar 23, 2009 5:59 pm
Location: TN. 50 years of gardening experience.

Bermuda grass is hard to kill the easiest way for me to kill it is till the soil every day during the month of July and August it keeps the roots from taking hold they dry out and die. All that tilling makes the soil dry out and brings the roots to the top. At the same time I pick up all the pieces I see and burn them. Problem is the bermuda grass creeps back into the garden from my yard.

Another way to kill it is cover the soil with black plastic all summer. The solar cooker will kill everything dead. It also stays dry because rain can not get in.

Another way to kill it is a large bonfire. Collect all the wood and brush you can find pile it 6 ft deep in your garden and set it on fire and keep it buring for several hours. It will cook it to death.

I tried Roundup but all that does is kill the tops not the roots.

A very heavy dose of SALT will kill it. Cover your whole area to be killed with about 3" of salt and till it in. It has to rain about 10 very hard rains for all that salt to go away bermuda grass will be dead so will everything else. 50 lb bags of rock salt are cheap.

I have a 100 ft long cement driveway I hauled garden soil and dumped it on the driveway this summer in July. No rain in the forcast for weeks so the dirt dried out as dry as the desert. We drove vehicles on it for 2 weeks. That grass is very slow to die I raked through the dry soil and found pieces that were still alive a week later. Then I had to shovel it all back to the garden.

SoCalVeggieGardener
Newly Registered
Posts: 5
Joined: Tue Nov 22, 2011 10:55 pm
Location: Pasadena, CA

Getting back to the original idea of the weed fabric under the raised bed, I would advise against it. The bermuda will find a way through...trust me. In the past I have had kikuyu grass grow through a 2.5' layer of soil in a raised bed. I wasn't too happy about that. Also, the fabric will restrict beneficial organisms, such as earthworms, from getting into your soil.

However, something I haven't seen mentioned yet is use of chicken wire on the bottom of your raised bed. This will help deter pests such as gophers, yet still let all the beneficial organisms in. I'm not sure if gophers are a problem in your area, but if they are I would definitely recommend the chicken wire.

Hope this helps!

dustyrivergardens
Green Thumb
Posts: 617
Joined: Sat Dec 03, 2011 1:32 pm
Location: Holbrook Az. zone 5b

Man I am sorry I have a Bermuda issue also I have been fighting it for 25 years. Fight the good fight man it is hard to keep it at bay.

tedln
Super Green Thumb
Posts: 2178
Joined: Thu Jun 25, 2009 10:06 pm
Location: North Texas

I put down cardboard in my deep beds and it did prevent bermuda grass from growing up through the deep soil. It also spreads by seed so I pull three or four tiny grass sprouts every time I visit the garden. It takes about ten seconds to accomplish and keeps the grass under control.

Ted
I simply enjoy gardening!

seedsowing
Newly Registered
Posts: 7
Joined: Fri Oct 28, 2011 12:37 pm
Location: Lubbock, TX

Fight the good fight

Yep - that's my plan - yank or dig out the grass that does manage to get in the beds. I just want to get my hands dirty. We order the lumber for the raised bed. It should be here next week. Hubby and I will be busy building and filling with dirt. I can start putting out seeds at the end of January. Can't wait.
Seed Sowing in Lubbock

tedln
Super Green Thumb
Posts: 2178
Joined: Thu Jun 25, 2009 10:06 pm
Location: North Texas

Re: Fight the good fight

seedsowing wrote:Yep - that's my plan - yank or dig out the grass that does manage to get in the beds. I just want to get my hands dirty. We order the lumber for the raised bed. It should be here next week. Hubby and I will be busy building and filling with dirt. I can start putting out seeds at the end of January. Can't wait.
Seedsowing,

What kind of seeds will you be planting in January? We grew up and raised our kids in Amarillo so I know what gardening is like in the panhandle. January was normally the month I checked the woodpile to see if we had enough to feed the fireplace for the remainder of the winter. I can't remember ever getting my hands dirty in the garden in January.

Now we live about 60 miles north of Dallas and the only thing I can plant in January are my onion seedlings. Everything else waits until early March.

Ted
I simply enjoy gardening!

seedsowing
Newly Registered
Posts: 7
Joined: Fri Oct 28, 2011 12:37 pm
Location: Lubbock, TX

Oh since this is my first year of gardening, maybe I am being optomistic about planting seeds in January. Maybe I should be thinking of planting seeds indoors and transplanting at the end of February or early March. In Colorado, from which I came, I could put anthing in the ground until Mother's Day. And even then it ws if-y.

I am just so excited to have a longer growing season and be able to plant three crops - spring, summer and fall.
Seed Sowing in Lubbock

User avatar
Tilde
Green Thumb
Posts: 344
Joined: Tue Sep 06, 2011 5:56 pm
Location: Hurry-Cane, Florida USDA10/SZ25

Your last frost date is around apr 15; can do a lot of indoor starts before then ...
USDA Zone 10, Sunset Zone 25, 16 feet above sea level, surrounded by chem-turfers.

tedln
Super Green Thumb
Posts: 2178
Joined: Thu Jun 25, 2009 10:06 pm
Location: North Texas

Starts indoors will work. You will probably get a few frosts until mid April. Some things do well in the cooler weather like lettuce and radishes and a few other things. Plants like tomatoes can easily be killed by a late frost. Plants like cucumbers and squash you can start inside and plant outside after the last frost. I plant some seed outside knowing they won't germinate until the soil temp. is right and that probably won't be until after the last frost.

If you do plan on starting a few plants indoors, you will need sufficient indoor lighting or a window with good southern exposure.


Ted
I simply enjoy gardening!

seedsowing
Newly Registered
Posts: 7
Joined: Fri Oct 28, 2011 12:37 pm
Location: Lubbock, TX

Excellent advice. I just pray that we will have more rain next year. It was so dry & hot. Everyone told me that was unusual. We'll see.

Of all the seeds I planted this year, my only harvest was one kolhrobi. I savored it. The flower seeds that I saved from my Colorado garden came up - mostly zinnia, marigolds, and cosmos.

I've started a spreadsheet for companion gardening -- it includes when to plant, good & bad neighbors, and when to expect to harvest (I have other colums too). Still working on it. I started a website all about my Lubbock gardening adventures.

Thanks again

Jan
Seed Sowing in Lubbock

Return to “Vegetable Gardening Forum”