Does a pond hole have to be perfect before underlay and liner installation?

[Lisak1]

I would definitely get my money's worth out of that liner. While everyone says "don't cut off the excess in case you need it later" concealing SEVERA FEET of extra liner is going to be impossible. Most of our liner - when we were done trimming - was less than 18 inches around the entire pond, and even that was challenging to conceal in some spots. Just remember you can always cut more off, but you can't put it back once you've cut it off!

With the amount of excess material that you have, if you don't decide to dig bigger, I would position the liner so you have to majority of the excess along one side, so when you trim you're left with a few big, useable pieces instead of a bunch of strips. We way oversized our liner too, but by being smart with the trimming we were able to use two big pieces for other projects and I traded a few other good sized pieces with a local pond store - they used it on a project for a stream bed and I got a piece of hose that I needed.

 

[Heruga]

Thanks everyone for feedback. I decided to expand my pond a little and perhaps also create some shelves for my marginal plants to grow in. One question is, do the liners have to be placed on the shelf and you put soil on it? Or do you put the liners over the shelf and then above on the edge and just cut off the liner on the shelf?

 

[Lisak1]

Look at @addy1's drawing above. You want your liner to come up and out of the pond and behind the edging rock. You then fold the liner down behind the back of the rock and fill behind it with soil to conceal it. Like a sandwich with rock on one side, dirt on the other and liner in the middle.

You don't need dirt for marginals - they can grow in gravel or even just the water if you anchor them with rocks until they get started.

 

[JamieB]

The shelf’s should be covered in liner. If it’s below the water line, it’s covered in liner. The purpose of liner is to maintain water in the pond. It looks like you have about 3 ft extra to each side. I would dig a deep spot in the center to allow mulm ( fish waste) to settle, and allow a place for fish to hide or for very bad winters. I would also dig a shelf about a foot deep, foot wide all along the sides, then a small shallow shelf about 4 inches deep for rocks to rest on to hide the liner.

 

[addy1]

One question is, do the liners have to be placed on the shelf and you put soil on it? Or do you put the liners over the shelf and then above on the edge and just cut off the liner on the shelf?

See the black line in the picture that is how the liner should be placed up and out of the pond. It makes a beautiful edge for your pond, no liner showing when done.

 

[Heruga]

Ok so the green in that picture represents plants and the gray would be rock. So even plants like acorus gramineus can grow in just water or gravel? They are one of the marginals I plan on growing in my pond. And I guess to prevent them from falling into the main pond, you put bigger stones around the plant to keep them in the shelf?

 

[poconojoe]

I also did what addy describes in her drawing. This method helps hide the liner when it transitions from water to the land. It makes for a more natural looking pond. Who wants to see a rubber liner between the water level and the ground?
I see so many ponds where several inches of liner are exposed there.

By making a very shallow shelf, you can place stones on that shelf so that the stones are half submerged. Then stack more stones on top of those but step them back, away from the pond. Keep adding stones or if you have a lot of excess liner, fold it under the stones.

For those that already have filled their pond, you can do this even with the water in the pond. I have done that. Just lift the liner, dig a shallow shelf lay the liner back down and add your stones.

 

[Heruga]

I guess then I will make a shelf all around the entire pond so that the edges will look more natural with the stones being partially submerged in water. And then leave some open or at least use smaller stones to hold onto the marginal plants.

 

[poconojoe]

I guess then I will make a shelf all around the entire pond so that the edges will look more natural with the stones being partially submerged in water. And then leave some open or at least use smaller stones to hold onto the marginal plants.

Yes, in essence you will have two shelves. A deeper one for your plants and a shallow one for the stones that hide the liner.

 

[Lisak1]

@Heruga you will find that when you plant things in the margins of the pond, you can use a variety of techniques for doing so. One thing I did was use small boulders (like baseball sized) and create a ring. Fill the ring with gravel and plant your plant into the gravel. If you need your plant lifted up higher (deeper shelf or a plant that wants to be higher in the water) just use larger boulder and more gravel. And depending on the spot, you may not need a whole ring - maybe just two or three just to create that spot to plant. Or you may be able to tuck plant between two edging rocks. In a couple of spots, we placed a second big rock further in on a wider shelf so we had a natural space between the two rocks for planting. You may just need one rock to anchor the plant until it gets started.

I had some plants that I started in those fabric planting bags you can buy for pond plants and when they got too big that they were bursting out of the sides, I literally chopped the bag in half, opened it into two half circles and put the flat sides up against the side of the pond wall. Instantly doubled the size of the plant!

Another good way to soften your edges is to plant things outside of the edge of the pond, in the soil. Things that like to creep will creep into the pond and fill those spaces between the rocks - maybe even hide them to some extent - so you get that "where does the water end and the land start" look.

A common mistake you want to avoid is the "ring of pearls" look - one size of rocks placed in a circle all around the edge of the pond. Even the prettiest rocks look unnatural when they are all lined up. When your edge rocks are partially IN the pond, you can really play around with them with bigger sizes, flatter stones, etc and break up that look. Even add some other elements like pieces of wood or smaller cobbles... so many things you can do!

This is an excellent video series that will walk you through the whole process. The Pond Digger does a great job of taking you step by step from start to finish - I highly recommend it.

Here's the one on edge finishes:

 

[Heruga]

This is my progress so far.. expanded the pond and made a shelf all along it. Except now I made the pond too big and the liner and underlay came too short. I added more soil in each opposite side of the shelves but it definitely does not give a foot long overlap... sigh there is always an obstacle in this no matter what.

 

[addy1]

Put the liner in and back fill the shallow shelves. IMHO you don't need a foot long overlap. I just had inches in some places, most was only 6 inches or less.

 

[Lisak1]

12 inches is extremely generous. Don't overthink it. If it's too short in an area, like @addy1 said, just place the rock, pull the liner up behind it and back fill up against the rock. You don't even have to fold the liner down - mine isn't folded in a few spots where we changed the edge or came up a bit short.

 

[Corgi Mom]

Perfect as in completely smooth and level on all sides. My 7x7 ft diameter circle pond hole has a lot of rocks and junk in it. I can definitely level out the bottom with sand but the sides of the hole is the main problem. There are so many voids and open pockets from all the rocks that were removed and is impossible to level out smoothly. Do I really have to smooth out the sides or will I be ok? If not, how do I go about this? It's almost like swiss cheese.

Some people use old carpeting to line the pond underneath the liner. Go above the pond around the perimeter as well. That protects the liner from punctures and smooths out the soil.. Cut in strips to make it easier to use and remove any staples. overlap each piece by a few inches. I would also make your pond larger. You’ve certainly got enough liner.

 

[Heruga]

Well so far I was able to add more soil to the shelves and somehow made the underlay and liner fit and then I placed all the stones on the shelf and filled it with water. One problem is the right side you see there is kind of overflowing and the left side has a couple inches with no water... I’ve made an uneven pond. Do I just add more soil to the side that’s overflowing and make it higher so the water will naturally flow back on the other side as well?