My new school has a beautiful garden, but it hasn't been maintained and is full of weeds. This winter I tried cardboard and pine straw, but the grass grew through it. How would you tackle this project?

We tried cardboard.

The grass even grew through a whole bag of pine straw. As I was hand weeding one of the beds I found these white tubers. I'm thinking about spraying with something or removing all the dirt and starting over with new dirt.

Ouch

What kind of grass, do you know? If it's nutgrass or Bermuda you have a tough chore in front of you. When using cardboard or newspaper, it needs to be laid down where there are not any cracks and in a thick layer. I use my cow feed sacks and layer them 4-6 deep at least and make sure there is lots of overlap at the edges and then cover it all with a solid layer of mulch. It works on nearly everything, but Bermuda will find it way up through it and it doesn't deter the wild onion at all as far as I can tell. I guess their growing point in the spring just pierces through all of the layers. I would expect nutgrass to be a lot like the onion. Bermuda roots can just live a long time under the layers and wait for enough decomposition to occur and then they'll surface again.

You might try again with a thicker layer of cardboard - no cracks or seams. Otherwise options may be to dig out and replace the soil or use a herbicide and see if you can kill everything, but even that's going to be hard if it's Bermuda or nutgrass.

Donald is right. The cardboard needs to be against the ground. Then cover. Plastic or landscape fabric (double layer) and weight that down with rocks or any thing you have. You are not going to leave the plastic or landscape fabric permanently. Just an inexpensive way to help block sunlight and water. Sometimes I have to add more cardboard and sometimes make multiple layers of every thing. You may have to cut the cardboard into pieces to fit it in flat. Good luck and joy to you! May there always be a cloud over you as you work outside.

Also, if you can stress the weeds first, weed whacker and pour boiling water over. I think chemicals may be a no-no being school property.

Tabitha,

I am not sure where the offices of the Ag Extension is currently (if you go to there website it says they are temporally moved due to our past flood) (Bear Creek ALWAYS floods , not sure why they have a place there anyways............but I would take some more pictures of the grass and shoot an email over to harris AT ag.tamu.edu and see if they can direct you to a good contact.

There is bermuda, nut grass and lots of other fun stuff.

In January I put down 2 layers of cardboard that overlapped and put 6-8 inches of pine straw on top. I left two full bags of pine straw to use on the next bed, but never had time to come back to it. In May you couldn't tell there was ever cardboard and the grass grew through the two bags of pine straw. The bed with the grass growing through the cardboard was done by another teacher, but I posted it just to show how hardy the grass in Texas can be.

Bermuda and nutgrass will be tough. They'll encroach from the sides and underneath any cover and wait their opportunity to invade over and over again. I'm not sure how well any chemical works on either of them. Seems like they will rise again no matter what you do. Maybe someone will have a better answer or solution. Good luck!

Randy Lemmon has a article on nutgrass http://www.randylemmon.com/law...
then on his Facebook his top post is about Bermuda https://www.facebook.com/Garde...

I would turn all of the soil that you can without hurting any of the plants, and get rid of all the grass. Then place at least two layers of black plastic flat on the ground and cover that with a layer of crushed rock. As folks have stated above already, the plastic MUST be flat on the ground.

Good luck

Years ago when I was wanting a new bed, I knew the Bermuda was going to be a problem. I wet the area and put cardboard down, no cracks and thought the Bermuda would even push through with rocks on top. The only thing I could think of to weight it down, and get hot enough to burn the grass, left over roof shingles. They worked like a charm. If you don't have any or enough. Decades ago when I was teaching stores gladly donated supplies for school gardens but parents might be looking to get rid of the shingles also
Good luck

Elbowgrease...needs more people working on it more often.

Nothing will get rid of the bermuda except chemical weed killers (more than one application) and/OR digging by hand, and it will grow back, and you dig it again, several times until it is gone. It will still sprout by seed, but the mature rooted ones will need to be dug, even a small piece will grow back and they grow out also on runners, anywhere it touches the ground it will root.

There are 4 beds that were hand weeded that have vegetables in them, and 12 beds that are nothing but grass/weeds.

Tabitha--Probably should have asked the 12 beds that are grass and weeds what do you want to plant in them? I feel your pain and frustration. Weeds and grass grow all year even if it looks brown on top the roots are still growing strong.

If your area has a Master Gardeners chapter, get in touch with them...they would probably be motivated to help with any problem with school gardens, since that's one way young people get interested in gardening.

Actually, coastal bermuda doesnt like being smothered. Sedges are a problem too. I wouldnt plant in ground. Plow it, smooth it, smother it. Thick black plastic, thick cardboard, wider than the whole garden. Then build raised beds- fresh dirt. The old dirt has many decades of seeds setting in it waiting for same things your veggies are. Water, fertilizers, sun. You would never know if you killed the original plants or not. Raised beds are above where winds and seed throw can get. Drifting soil and seeds are easier to keep cleared away. No poisons in the soil for plants to uptake. Increased yields in raised beds.

Spring, it's almost impossible to stay ahead of things that grow here. Even in raised beds, weeds show up, because plants throw their seeds, rains and breezes carry seed. We don't really have grass come winter, but enough weeds to make lawns look lush. Were you in the Harvey floods? Hope not. Wierd summer here- my mustard didnt bolt, I have plants showing rust of all things, the floods 3) 500 yr floods ) left 6" of silt sand on the St Augustine. Stay well