It often does grow through unless you kill it off first. A very common recommendation is to first lay down several layers of cardboard and build the bed on top of that. Over time the cardboard will break down/decompose and in the mean time it will have smothered the grass and weeds that used to grow there.

The alternative of course is to rent a tiller and till the area first killing the weeds and grass in the process and then build the beds on top of the tilled area.

How to build raised bed discussions

Dave

It somewhat depends on the grass. Blue-grass and probably St. Augustine type grass will die with deep soil burial. Bermuda will laugh it off and be endemic in a few years.

My thing is making sure there is enough room between beds to maneuver a wheelbarrow. I had a narrow area when I started and only had about 24" paths between the beds. This was a mistake! IF you have the room, do 3' paths. It will make it so much easier to turn and dump your compost/soil.

When I've built each bed, I've forked down as deep as possible, breaking things up as much as possible, add Horse/goat/chicken/imu/rabbit/sheep/whatever manure, water it in, water it in again and again. Build your boxes, line them with hardware cloth if you have gophers, start filling with soil (We buy from a landscape place to start), watering in as you go to fill the gaps. We fill to the brim knowing that all that stuff will break down.

Have fun! Nancy

Thanks for all the tips! I think I'm going to set up the beds today, as it has finally stopped raining (temporarily). I have several old cardboard boxes waiting to go in the trash, so I think I'll try lining the bottom with those and see how it goes. I called a local nursery which sells bulk soil, and that seems to be the cheapest way to go, although I'm going to have to pay for them to deliver it, since I don't own a truck. Apparently, the soil is just loose, so there's no way for me to haul it in my SUV. I need 48 cubic feet, plus some extra to top off some containers. I'll take photos as I progress! My seeds have all arrived, but I'll be starting most of them indoors, and the others I'll plant outside later in the season when it warms up. Tomatoes (Cherokee Purple, Chocolate Cherokee, Sara'a Galapagos and Mexico Midget), melons (Charantais and a small watermelon whose name I can't recall), a wild Alpine strawberry and some regular strawberries-- I may plant those in the side yard--, sunflowers (I can't remember the variety) and milkweed. I also plan to plant carrots and broccoli in the late fall, as a winter crop. I used to have a garden every year in my side yard, but haven't the last 4 years because my small children take up all my time, but now my youngest are 2 (twins), so I'm hoping they and my 4 year old will enjoy "helping" in the garden and eating the fruits of our labors. My side yard has more shade than most veggies like and the soil here is terrible, so I'm hoping the raised beds will give me better luck than my side yard did, with less work amending the rock-hard clay soil.

Oh, I have no idea what variety of grass I have, and I've never had gophers, though I've heard of some people in the area having trouble with them. I do have squirrels, birds, and (ugh) rats. Something took one bite out of every not-quite-ripe strawberry several years ago. I tried to tell myself it was squirrels, but it happened either during the night or very early in the morning, so I'm afraid if may have been a less cute rodent. I just wish it was smart enough to figure out if the first one was sour, they all are! Why did it take one bite out of each? They all taste the same, dummy!

it could depend on how deep your raised beds are going to be and whether or not you plan on using the soil below the raised beds as part of your plan. I used to have 6 inch raised beds which obviously I also needed to incorporate things growing down beyond the 6 inches as well. If your planning on putting in deep raised beds in the 18" on up range and not use the dirt below it then Id probably put down two layers of cardboard and/or a couple layers of weed fabric. Putting a foot of soil on top of weeds and some grasses by itself will do almost nothing to stop them. There are other ways that would take longer such as killing it all with grass killer which could take several spraying treatments(and leave bad residue behind) or covering the area with black plastic until everything is dead. Both of the latter are quite time consuming

If your neighbors have problems with gophers, I would go to the extra expense/work to add the hardware cloth. Those little suckers SMELL veges growing!

You don't want to have to dig everything out after the fact and re-do your beds!

Nancy

I have just finish for the day building raised beds. The first thing you should do is take a soil sample from your existing soil and have it tested at your county extension service in your state, usually a state college has one. They will send you a soil sample test kit for $ 20.00.

I till the existing soil to a depth of ten inches and add peat moss, compost, aged animal manure to the existing soil.

I then build raised bed frames of no less than 12" depth. You can go to your local Home Depot to see if they have any cull lumber. Cull lumber is slightly damage lumber that you can buy for a 70% discount.

This is all for now. I have more information to offer.

If you're not sure what kind of grass you have, looks at how it grows. If it has long runners underground, it will come up even when buried. If it's in clumps, then cardboard should work fine.

So, I put together the beds and put down the cardboard lining today. Here is what it looked like before:

And here it is now, waiting for soil:

I realized that I actually could build another bed, because each kit contained four sides (two 2x4's each) and four posts, but since I butted them against one another, they share sides and posts. So, I used the extras to build a 4th bed! I pulled up some of the larger weeds, and found there is plastic netting under the grass, so, hopefully that will help if anything tries to dig in. I doubt anything will, though, since nothing did in my side yard garden. I called and compared soil prices last week, and found bulk soil from a nearby nursery is the cheapest way to go, so I plan to call next week about having that delivered, then buy some manure to add.

It's looking great

You have the beginning of a lasagna garden. If you can add some grass cuttings, dead leaves, newspaper in layers. You can plant plants directly in the layers. They will grow. Don't forget to fertilize.

len

Soil will be delivered Tues. I asked the guy what kind of soil, and he said it's their vegetable blend for raised beds, and that I wouldn't need to fertilize for at least a couple of months. Do you think that's true? I should have asked what's in it, but didn't think to do that. I bought a soil tester a week or so ago; one of the battery-operated ones with probes that go into the soil. It tests Ph and "fertility" which is basically the amount of organic matter in the soil. It doesn't separate the N, P, and K. So, I tested several spots in my side yard and my pots outside, and they all said 7 Ph and all were in the middle of the "not enough" area for fertility. It seemed odd to me that all of that soil would be exactly the same, so I put the probe directly into a pile of dog poop in the yard, and it gave a Ph of 7 (I actually looked up the Ph of dog poop, and it ranges from 7-7.5, so that may be right), and it said fertility was "just right." Shouldn't it have registered as too high? So, I'm wondering how accurate that gadget is. Anyone ever used one? Maybe I should post that question seperately. Anyway, I think I'll check how much organic matter the things I'm growing like, and probably add a little chicken manure to anything that likes especially rich soil., regardless of what the guy at the nursery said.

Len, I've heard of lasagne gardens, but never tried one. Not sure if I have enough grass clippings or leaves to make it work. Plus, I've just never done it before, so I'm leary... Prefer to stick with what I know. Have you done a lasagne garden before?

I've seen these "pH and fertility" testers, and while pH is a pretty straightforward measurement, I don't have a clue what "fertility" is actually measuring. One vendor talks about "pH or fertility" being measured, which is nonsense. Some plants like acid soil, and some like alkaline soils, so pH isn't fertility. I can't understand how an electronic probe is going to measure "organic matter". For the cost of one of these testers, you can get a thoroughly responsible laboratory measurement of many soil parameters from your Ag extension. I should say that home soil chemical tests are well understood to be pretty bad.

You can get a rough handle on organic matter content by swirling some soil in water, and letting it settle. The carbonaceous stuff will float to the top. Just compare the thickness of layers that precipitate. The main laboratory test for organic matter is to take a dry soil sample and burn it. Weigh it before and afterwards. The organic stuff will disappear after the material is burned and the mineral component will stay behind.

yes! I have. They work well when you are in a pinch for growing medium. As it decomposes it feeds the plants. You continue to add material as needed and keep it moist.

The soil you purchased is a mix of compost and some top soil. Normally compost would have a PH of 7.0. If your total PH is between 6.2-6.8 that is ideal for the majority of vegetables.

Nice looking project!

I built a raised bed for 2015. Posted a few photos taken during the process here on GW.

When I pulled the plants for fall clean up (various pepper, tomato, squash and the like) I was surprised there wasn't a larger root system. I placed a prepared soil blend with slow release fertilizer around each plant location when setting out the seeds or transplants last spring, rather than try to condition all the new soil just placed in the bed. Judging by the harvest and root systems of the pulled plants, this worked well.

I continue up to work in compost and other amendments so look forward to an ever more productive harvest in the raised bed here in 2016.

Good luck with your planting this year.

I prepare my existing down to a foot after a soil test tells me what amendments are needed. I work in peat moss , compost and add lime, gypsum for raising the calcium and lime is for the acidic peat moss to raise the PH.

Len

Those raised beds are looking amazing! I am thinking about putting some in as my hip can no longer take the pain of kneeling on the ground for too long. Does anyone have any ideas of what I can use in the meantime to get my hip back on track?

Maybe something like this;

http://m.costco.com/Gronomics-Rustic-Elevated-Garden-Bed.product.100140667.html

Or this fancier one:

http://m.costco.com/Gronomics-Deluxe-Elevated-Garden-Bed-with-Trellis.product.100080827.html

Ypu wouldn't have to bend to use them (depending on how tall you are, I guess.)

Silly me, I thought when they delivered my soil, they would put it in the beds. No, they just dump it on the driveway. Seems like for the $50 delivery fee (from about 10 miles away), they could at least move it to the back yard.. Anyway, here it is, after my husband had already moved about 4 wagons full.

I don't know why the photo didn't show up the first time.

over five yards in my area, shipping is included $25 a yard. They gave me seven yards.

The place I called includes delivery only if you buy over 100 yards or something like that. I neede enough for 4 beds 4x4x16in., so approx. 64 ft cubed. I guess that's about 21 yards, if they just divide the feet by 3? Anyway, I paid about $150 total and ended up with about twice as much dirt as I needed. I put the extra in my side yard, where I usually put my garden, and plan to put my overflow this year. My eyes were bigger than my growing space, so I bought a lot of seeds. So, the extra dirt will keep me from needing to amend the soil, I hope. Nothing has been planted there in about 4 years. We had to shovel dirt all day for 2 days, as rain was forecast for yesterday (it ended up not raining until last night), and I wanted to get all the dirt off the driveway before the rain washed it down the street.

Here are the filled beds:

The petals from the nearby plum tree blooms blew all over the top of the dirt, so that's the pink specs you see. It was quite beautiful when I was hauling the dirt and petals were blowing everywhere in the wind. It looked like it was snowing. My asthma didn't like it, but it was lovely.

And, my seedlings:

Ive got some cukes and milkweed and a few tomatoes sprouting!

Wow Brigid everything looks great! Lucky you have petals blowing, we have real snow and lots and lots of it!!! Has been very cold here in Ontario (-26) !! Enjoy your planting :)

You divide the cubic feet by 27. 3 x 3 x 3= 27 cubic feet. You received 2 1/2 yards. The soil you received has quite a bit of air in it. If you compress the air out of it, it will fill your beds. However you don't want to do that. It will occur as it rains, and will settle forcing some air out. each fall you should add compost. Do you have a compost bin. Composting your table scrapes with grass 20% and brown matter 80% produces some find compost

One mindset I try to change in gardeners is, it is called earth or soil not dirt. Dirt is what you get it on you. Earth and soils are living things. 100 million micro organisms per teaspoon. It is living so you must feed it. In turn it will feed your plants and the plants will feed you.

Yes, I meant soil. I did walk all over it to press it down to make room for more, and we did fit in more, but still had about twice what we needed! I just told them the size of my beds and let them tell me how much I needed. Anyway, the extra went to top off some pots in the back and into the aforementioned side yard, so it was okay. It was still cheaper than buying bagged soil.

Why didn't my emoji show up? Yes, I meant soil :-).

Anytime you can buy in bulk it is the way to go, if you can use the bulk quanity.

I had that issue trying to buy bulk peat moss this season. The bulk peat moss would be delivered in a 2000# compressed bulk. Enough to do twenty times more then what I needed. I resorted to purchasing 5.5 c.f. bags at $15.00 per bag.

How are you going to reach into the center back bed without walking in your raised beds?

They are only 4' x 4' beds. You might have some reaching from the inside corners.

Most gardeners will figure out what is most comfortable and will make it work.

I can reach pretty well from the corners. Or, if I have to I can squish myself in front of the bushes.