I built lasagna type raised beds last year by layering cardboard, newspaper, compost and soil.

I've turned it this spring to see how the layers looked after a year. Amazingly, there were a large number of earthworms and the cardboard layers have been breaking down into a rich soil There was no evidence of newsprint as it had totally composted.

I am planning to build another bed or two but am running late for this growing season.

I've not used cardboard for weed suppression but that is good to know. Thanks for sharing those links.

I had never done any kind of layering before, so about 6-7 weeks ago, my first 4'x8'x12" raised bed of this year started with me removing all the soil from last year, which involved cutting and removing about 20# of bermuda grass rhizomes that had grown underneath it and up through it. I then soaked the soil with vinegar, then laid in several layers of brown packaging paper and backfilled with last year's soil and about that much more new mulch. Seems to be keeping the bermuda grass at bay so far, even after multiple deep waterings. Now we have beets, spinach, jalapeños and cayenne peppers started and happy.

In the fall, I'll do it again, but probably add more layers of newspaper, cardboard, leaves, manure, etc. Also probably get some "free firewood" from craigslist or tree trimmings from local bulk trash pickup days. Lots of that available around here. Just have to wonder about how organic that stuff could be. Guess I could ask homeowners if they spray their trees.

My current winter bed as of Jan 11:

I always start my lasagna beds with cardboard (flat type, not shiny) on the ground and have had very good success. Done in the fall they are usually great by time for spring planting.

I'm wondering if there's anybody else in AZ or other hot regions that constantly battle with old-growth Bermuda grass or St. Augustine constantly invading, and if they've had success with lasagne layering. Susie?

I have found that thick layers of cardboard will stop just about every weed, including some of the bad ones like nutgrass and bermuda. It doesn't stop them from creeping in from off the bed, but it does stop it from coming up from under the bed. At least, that's my experience.

Mine as well. I am not in AZ but I have hot summers and old growth Bermuda grass (43 year old property) here. The only thing I know of that will slow it down without using poisons is shading/covering it with something.

This lasagna bed was new last year. I bordered it as shown, border slightly pushed down in the ground so that the Bermuda tends to want to grow up the side of the border more so than under it ... and is easier to pull/cut. I had the ground around it covered with bunched up landscape cloth to shade it (removed it for something else later) and you can see that the Bermuda is just now starting to invade that outer area in this shot on Sept. 1.

Bermuda does go dormant in the winter here so we are fortunate in that way.

I have used cardboard and newspaper in the past but I found termites liked it and it looked terrible where it became exposed. Not knowing what chemicals went in to the manufacture, or into the printing inks, finally put me off it. Don't use it any more. If plantings are fairly dense weeds become very leggy and are easy to pull out. Other than that, I regard weeds as a temporary nutrient storage facility.

Tee, that's a very nice Colocasia 'Tea Cups'.

Thanks, Zig. I was very pleased to get that 'Cups' at out local Farmers' Market for $3. Score! It's in the ground now and I'm anxious to see it again this year soon. Love those EEs! I image you have a lot of them.

Alas, Bermuda grass has underground runners, runners on top of the ground, and it seeds like crazy. It's one determined-to-survive grass! And it is not so easy to pull out and impossible when the ground is dry. It also forms a solid mat that is just about impossible for anything to grow through or penetrate. Sometimes you have to take desperate measures and flat, dull cardboard is the lesser of all the evils, I think.

I agree wholeheartedly about the weeds. They aren't so bad once you come to terms with them.

Give the Tea Cups a lot of water, mine are growing in shallow water. They send out a lot of little runners which send up new plants. They really multiply fast (maybe not as fast as Bermuda Grass, LOL). I have a few nightmare grasses but not near the gardens. The seeds are carried around by animals and surface water. The water movement I'm controlling with swales. The weeding is still a permanent job. But I agree, cardboard is the best to combat grasses like the Bermuda Grass you describe. I tried some of what we call "weed mat", a tightly woven plastic cloth which allows water through but not weeds. After a number of years roots manage to grow through it and then it's impossible to remove. At least cardboard breaks right down.

Thanks, Zig. We do get about 52 inches of rain a year here but summers are hot and often very little rain during those hottest months. I may end up moving the Cups to another location. I wouldn't mind if they took over the entire area.

I'm afraid I've had that same experience with the weed cloth. The roots do tend to penetrate it and fairly quickly. I've got some that was down for less than two years and quite a bit came through. It has worked the best here for me just sort of bunched up and tucked around the borders and barriers with mulch elsewhere. Well, gardening keeps us on our toes. It's "us" against "them".

I was initially put off the idea of making a lasagna bed because I thought I'd have to look at a expanse of mulch with nothing in it for an extended period of time. So, when I finally made one under the white birch I left spaces for a few holly shrubs, which I added right away, and then I added sunken pots of annuals while I waited for the materials to break down. This satisfied my "want-it-now" sense of visual appeal.

Good idea, Chelle. I'm the same way.

Now I am thinking about what Zig said. The EE I lost was a large common Taro (I thought). But perhaps too much water while dormant (although I only lost the one)? Sorry for the slight departure from the topic. This is the bed that gets the flow-through water from the seasonal stream in the back. Now I am thinking about raising some of it with Hugelkultur beds so wondering about planting EE bulbs in them.

Here the EEs grow all year and are okay staying very wet all the time. But if they go dormant from cold you shouldn't let them totally dry out, keep them just moist/damp. Kept too wet would cause rot. I think they'd do really well on the Hugelkultur beds in the growing season with plenty of water, they like a very organic soil.

I'm glad to know this. Thank you.

tropicbreeze: I wonder if a scattering of diatomaceous earth might help some with the termite problem in your cardboard and paper mulch. I use it for the ants that get in my dog's food. It is not poisonous to cats or dogs, and is quite effective on insects. It is available at Amazon. Most people buy food grade, but it is also sold for swimming pool filters.

RE the St Augustine invasion. This is the first year of 5 I've experienced it in my backyard lawn. I have Bermuda and overseed with Winter Rye... so the St. A has "never touched my lips". I'm pulling it out as it appears. Birds are amazing transfer agents. :(

Chris, I did the same as you re layering over Bermuda. Five years ago in heat of summer I pour Distilled Vinegar over a specific area and later layered with cardboard. RE using vinegar, you need to let the heat and direct sunlight hit the plants in order to kill or arrest it's growth. It worked.

However, I do experience Bermuda creeping under the concrete and brick separators between grass and beds. I dig up the rhizomes immediately.

Chelle, according to Pat Lanza, author of the Lasagna Gardening book, you can plant in your lasagna bed immediately after building it. I planted as soon as a few weeks after building.
http://ourgardengang.tripod.co...

Karen

Oh, that's great news!

This is the second year for the bed I made; it now has campanula, bleeding heart and columbine in addition to the holly and juniper. I had a terrible time keeping transplants in it last year....the nighttime critters kept digging them out. I'd have to check every morning to see which ones were salvageable and tuck them back in.

Susie, yeah IIRC you may be the one that originally told me about using vinegar for that very purpose, years ago on DG. I think you said to try to get 10% vinegar, which I never did. But Costco sells 1.5 gallon white vinegar for around $4, so I get a jug whenever I'm there. So far so good.

Horticultural vinegar is very different from the regular vinegar. Cooking vinegar contains no more than 5% acetic acid which makes it harmless to weeds and tough grasses for the most part. Horticultural vinegar contains more acetic acid which allows it to penetrate into the root system and kill them. Horticultural vinegar will damage some grasses and flowers. So good to avoid collateral damage or vinegar flowing downhill after being applied.

Edited to add that it also changes soil pH for a time until rain or watering or other forces of nature dilute it.