I have never heard of laying down plastic. Maybe if you post a picture it will help us understand your question.

The ground should slope away from your house so that any water runs away from the walls. The plants should not be planted right against the house.

If this is some kind of plastic waterproofing system that I have not heard of, definitely do not cut holes in it.

Plants need water at their roots and a of sheet plastic is not going to keep water from seeping into a basement that has not been properly water proofed.

There are systems for basement waterproofing that can be applied to the inside and outside walls of your foundation. The exterior ones are done in connection with a French drain that channels the water away from the foundation.

There is landscaping material designed to act as a weed barrier. You have the dirt, the permeable weed barrier and then mulch. You punch holes in it where you want to plant.

Might you be confusing these different projects? As noted above, there is no landscaping fabric that waterproofs your foundation.

Thank You guys so much for replying! I am sorry, I was not clear enough about the project we are doing.

We wanted to put down the film to prevent weeds but decided on a thicker plastic instead because someone told is that the plastic will work in the same way as the film barrier but also protect the foundation too against water especially as it is very old..

Landscape fabric is the stuff that prevents weeds. It lets water through, because the plant roots need the water. I have never heard of using plastic like this. Laying some plastic on the soil will not protect the foundation. You have been misinformed.

If its solid plastic, you can't plant on top of it, the plants need drainage.

Skip the plastic altogether. Not a good plan for the plants and will do nothing for the house. As a weed barrier, it's ephemeral. Maybe effective for a season or two. Then the weeds sprout on top the plastic! Save your money and skip it.

So you want to keep the foundation dry but the roots wet. What's wrong with that plan?

Don't forget, once water gets into the soil, it spreads out. You can't cover half a sponge with plastic and expect it to stay dry while the other part of the sponge gets wet.

The idea is to move the water away from the foundation in the first place--extend the downspouts, install a drain to the sewer (if legal), slope the yard away from the house, etc.

If you post over on the various gardening forums here at GW, eg perennial or shrubs, you'll find that both plastic sheet and landscape fabric are universally loathed and discouraged.

To keep the house dry you need a proper damp proof course of some description. I don't know how it's done in US. You can't do it via a gardening technique.

Grade should be pitched away from the house a minimum of 2.5% for runoff away from the foundation. Plant first then you can poly or "Plastic" the bed areas if your installing rock. Cut 18"-24" diameter hole in poly around base of plant for water infiltration. if your mulching skip fabric its only going to work year 1 then debris breaks down on top making the perfect hydroponic medium for weeds to grow. Hopefully this helped just ht to see bad information being thrown out there.

landscape beds with plastic are a nightmare that you will hate every day until the last scrap of plastic has torn off and blown away. Weed fabric is no better. Get the beds as clean as possible, use a pre-emergent, mulch heavily (keeping mulch off the plants), and stay on top of any stray weeds that do blow in.

Plastic will keep important nutrients from reaching your plants' roots and will create a mould issue in your garden. The soil needs to "breathe". Everyone has given great advice about dealing with the foundation issues.

Thanks everyone! You are all really helpful and I truly appreciate your inputs! :)

Just to clarify, we are not working on the foundation of the house. We are doing a landscape project only. The plastic question came up in our part du to that we were planning on putting down a weed barrier as we have done that in other areas and it works great. Then we were informed that if we were to make the choice of a thicker plastic barrier instead, that it would also do the foundation a favor at the same time. We started to google it but couldn't really find any great info on this. The foundation is a whole other project, nothing that we are focusing on right now but did not know if the plastic could help in any way if just a tiny bit with water.

We are planning to put small rocks and medium sized all over the area after planting as we Love that look and need a support for them not to sink and disappear into the soil. The project is being made in front of the house and that is also why we are trying to not get a lot of weeds as we would have to clean them up all the time and wanted to try to prevent that.

We know about the sloop that needs to be done away from the house so no problem there. We won't put mulch as we don't like the look of it in this particular area and don't need more insects close to the house.

Thanks again everyone!

The sad truth of it is that no matter what you put down, you will get weeds. Those darn things will grow anywhere. Sigh.

Yes you are right about that. The barrier that we have in other areas have done a great job protecting against the weeds wanting to come up but the airborne can't be prevented.

Pennie, your original post made it sound as if you had a foundation water problem that you were trying to solve. The benefits of weed barrier are short lived. Eventually, there will be enough silt blown and washed on top of it, and enough holes in it that weeds will be happy growing in spite of it. Later, weed barriers can make working in the yard more difficult. Or they can be hard to remove. Usually, most of us just use thick mulch instead and control weeds other ways.

To use just a weed barrier, it goes on top of the soil but under the mulch. In your case, you're using rock/gravel mulch. You'd make a hole/slit for each plant.

Many of us agree that landscape fabric is useful as a separator (and support) for rock mulch. In addition to keep rocks from sinking into the ground, it can aid tremendously in case one ever want to remove the rocks. However, this will only work if the weed barrier is WOVEN POLYPROPYLENE (like a trampoline fabric.) The plastic film barriers simply disintegrate to such weakness that they will not help when removing rock mulch, which is very heavy.

Thank you bunches! :) Yes, I realize I was not clear in the project. This will be great now and I feel excited for the outcome.

if you have a well sealed basement with no cracks to the foundation and good weeping tiles all around the foundation there shouldn't be water going into the basement at all, you re suppose to use landscape fabrics to avoid the bad weeds , poke holes in that and plant your flowers, bulbs or shrubs then cover with rocks or bark , keep it well watered too.

Most horticulturists and landscape professionals will avoid using or recommending any type of weed barrier/fabric for ANY purpose other than a hardscaping underlayment as Yardvaark has described above. It does not really help in weed suppression - a good layer of mulch will do that just as efficiently and without the fuss and bother of laying the fabric (and any future removal efforts) and it does impede or slow good water penetration, oxygen exchange and nutrient delivery. The benefits do NOT outweigh the undesirable characteristics!

Sure thing! But, we don't want the mulch and have decided on rocks instead which will need the barrier as a support to not sink down into the soil too much.

Rocks ARE mulch. Anything applied to the top of the soil like that is mulch. There's organic mulch (straw, bark, pine needles, etc.) and inorganic mulch (rocks, etc.)

NO plastic! NO fabric! If you use either, you'll live to regret it. If you have to have something under your rocks, use cardboard boxes broken down flat and wet with the hose.

Listen to the advice of all of us who have gone down this same path. Debris, leaves, dust, etc. will settle on top of the plastic/fabric. Weed seeds will fall there. The weed seeds will grow in the debris, their roots will squirm into the dirt THROUGH the plastic/fabric, and will permanently weld themselves into the plastic/fabric. It will be a mess. Trust us.

But Littlebug, the recommendation of FABRIC has nothing to do with weed prevention. It has to do with separating rocks from soil, supporting them from sinking/mixing, and greatly aiding in the later removal of rocks should the day ever come. (And it does.) Cardboard boxes have a short life in the soil and will not work to aide later removal of gravel mulch.

I'm jumping on the bandwagon saying no to plastic/fabric..I also hate rocks as mulch..the previous homeowners did this at my house..I removed it..rocks don't prevent weeds, don't enrich the soil, they radiate heat that can harm plants and collect debris..very hard to keep clean..good reasons not to use rock I think..

Well, we Love the rocks and the looks of them. We have them in other places and have never had a problem with keeping them clean. We haven't had any problems with heat eather.

I like rocks too (especially big ones) but I like plants more..I prefer more plants less mulch..

Yes of course the cardboard breaks down. It's meant to. No, it won't prevent weed growth long-term (I don't think there's much that will except concrete) but it WILL improve the soil.

But you're right - the OP may not be interested in soil improvement.

The main point I was making was that cardboard won't help in later removal of the rocks. Tough polypropylene fabric is necessary for that.

It's funny to me that even BEFORE the rocks go in there's a discussion about planning for easier removal..isn't that a clue that rocks are often unwanted eventually?

You've made an excellent point, Nicholsworth! Sometimes it is the installer, but often it is the subsequent purchaser who must face the removal task. The job will be a curse, and will be cursed, if there is not a sturdy separator fabric in place.

littlebug, as I have started before, all tips and suggestions have been great and everyone gives suggestions on What they think is the best Way to go. However, my question at this time was not about soil improvement but thank you for your input. I know about it but it's nothing that we are looking into right now.

The trick to water and old foundations is that your gutters, downspouts, and grading should effectively channel water away from your foundation.

Why is this even in the landscape design forum?

I'm sure the OP won't listen but add another vote against landscape fabric and rocks. The fabric will eventually break down and create a perfect environment for weeds. The rocks will eventually get clogged with dirt and silt and look ugly. It may be 3 years or 5 years but someone will eventually cuss you as they remove the mess.