Use Plastic Bottles to Make Pots Lighter
I use plastic bottles to make large pots lighter before I add potting soil. It makes pots easier to carry, cuts down on the amount of soil needed, and is better for shallow-rooted succulents. Before I plant any tall or large pot, I half-fill it with tightly capped empty water bottles.
Good design and aesthetics dictate that large spaces need large pots. They make a “wow” statement in any garden, patio, entryway or sunroom. Pots that aren’t in scale with a big space can be visually lost or add clutter.
This is Amy VanLiew’s garden. See more examples of large pots in garden spaces.
Problem is, if you fill a big pot with soil, you might not be able to move it, especially after you water it. And if succulents sit atop soil that never dries, roots may rot. My solution, a result of trial-and-error, also works for window boxes.
To make my deep window boxes less heavy, there’s a layer of plastic bottles beneath the soil.
Mistakes to avoid
— Initially I tried placing a succulent, still in its nursery pot, inside a tall glazed pot. The plastic rim showed, which looked tacky. I tried the nursery plant in a different large pot. The plastic pot dropped too far inside, making the succulent look like it was hiding. Not to mention I hoped to put more than one succulent in the focal-point pot. I considered half-filling it with rocks, but being denser, they’re even heavier than soil. As for lightweight organic matter, like chipped wood, it makes the soil level sink as it decomposes.
— I tried keeping the lower half of a large pot empty by using a pot saucer as a shelf inside it. It was tricky to find a saucer that fit and would rest where I wanted it to (about a foot below the rim). Plus it needed a drainage hole.
— Next I tried filling the bottom half of a large pot with styrofoam packing peanuts. Later, when I emptied the pot to reuse it, I discovered that wet soil plus styrofoam equals a sodden mess that’s no fun to dispose of.
— I also tried dumping clean items from my recycling bin into a hefty pot, but discovered that bottles and crushed cans hold soil and water—an anaerobic mix that becomes a microbial soup. Even bubble wrap, when stuffed into a pot, forms nondraining pockets.
My cheap and easy answer
I fill large pots half full with empty plastic water bottles, tightly capped. As far as roots are concerned, bottles are the same as rocks. Yet empty plastic water bottles don’t weigh anything. Some soil does fall into gaps, so it’s a good idea to pour pumice into the pot prior to adding potting soil. Pumice, a lightweight volcanic rock, absorbs excess moisture. Make sure bottles are tightly capped, so inside them is only air and the weight of the soil won’t make them collapse.
Empty water bottles make big pots weigh less, save on soil, prevent soggy roots, and are easy to remove when emptying the pot. Simply hose them off before returning them to your recycling bin.
Use Plastic Bottles for Lighter Pots
Step-by-step [see the video]
— Assemble your materials: Pot, plants or cuttings, empty plastic water bottles, potting soil, pumice.
— Place empty bottles in the pot to midlevel, or to about 12 inches from the rim.
— Add enough pumice to nearly cover the bottles.
— Remove plant/s from nursery pot/s and arrange in pot.
— Add soil so the crown of the plant (where roots meet stem) is a bit lower than the rim.
OR, if planting cuttings, simply insert them in the soil.
— Move pot to its new location. Protect flooring from drips if need be. Water lightly to settle roots.
— After a week or so, insert a wood chopstick several inches into the soil to check its dryness. If the stick comes out clean, add water until it flows out the drain hole.
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Txs. Good suggestions. However, would placing plastic water bottles with cap then soil be ok. Nothing else. And would crushed bottles without cap be ok.
Tee
Hi Tee, Yes you could do soil only. Re crushed bottles without caps, I wouldn’t, because water would still get into them and get skanky.
So, I had bottles without tops and it did leave a stinky, stanky mess. I’m assuming that I need to throw out this all out and start again, correct?
Oh, no! Yes, I’m afraid so.
Can I use lava rocks instead of pumice? I cannot find it in any of our garden and hardware stores. Thank you.
Yes, the finer the better. Pumice is volcanic rock, btw.
Thank you Debra! I never imagined I could work on plants and I just started now, in my 50’s. I followed your water bottle instructions and used lava rocks in a resin planter. Is there a way I can show you a picture of what I did so I can get some constructive feedback? Thanks!
Is it necessary to remove the paper off the plastic bottles
I don’t remove the bottle labels, which are generally a thin plastic. Paper might disintegrate and get a little messy at repotting time. The plants don’t care!
I have a cat palm o want to put in a very large pot that has no drainage can use this method?
NO. Please re-read the article. This method does NOT provide drainage. It merely makes pots lighter by using less soil.
Thank you, the plastic bottle idea is so good I’m going to use it as filler for my raised beds!
I’m glad! I use it all the time. One thing I’ve learned is to compact the soil and fill the container with as much soil as possible, because over time it’ll sink down and the tops of the bottles will show.
Hi Debra,
The plastic window box I’m using has a water reservoir at the bottom. Can I still use the plastic water bottles idea?
Joe
I don’t see why not. Sealed plastic bottles are basically the same (to the plant) as large stones that roots grow around. I’d be more concerned about “a water reservoir” keeping the roots soggy, leading to rot.
You mention succulents does this idea work vegetable and flower plants too?
Hi Diane — Succulents are shallow-rooted, and their roots are at risk of rotting when soil in a pot doesn’t go nearly dry between waterings. Vegetables and flowering shrubs, on the other hand, generally prefer deep pots and sustained soil moisture. So no, I don’t recommend the bottle technique for them.
Can I do this with a ceramic pot that has a built in saucer (i.e. it has a small drain hole on the side of the built in saucer? Just want to make sure it drains well with the plastic bottles and pumice.
Yes. A saucer that holds water will keep soil in the bottom of the pot wet, which can rot roots. Plastic bottles (which to roots are solid objects like rocks) and pumice, which absorbs excess moisture, should help the situation, because most of the roots will stay above them in the pot.
Hi Debra,
Appreciate the how to.. And looking forward to designing and creating succulent arrangements using this method. Thank you! 😊i
Can I use landscape fabric over the plastic bottles
Yes but why? I can see how it might make it easier to lift the plant and root ball out of the pot later on. But soil is going to sift downward around the edges of the fabric regardless. You’re also creating a root barrier which prevents the plant from sending roots deeper, which could inhibit growth and make the plant top-heavy. Here’s the thing to remember: Bottles, when sealed tightly, are the same thing to plant roots as rocks, except they’re lightweight. Roots follow soil into crevices.
Hi,
Would it be okay to use this method with plants that have lots of roots such as rosemary, mint or lavender? How about a dwarf lemon tree?
Hm. They have deep, fine roots and need more moisture than succulents. Maybe OK for herbs (if you have a tall, heavy container and they get at least 6 inches of soil) but definitely not the dwarf lemon.
Hi, i dont have pumice, so if i just use the bottles and soil, will that be ok? I picture the soul eventually sinking in between the bottles and maybe clogging drainage holes?? Thanks for any input.
Hi Donna — It’s fine if you use potting soil (sold in bags at any nursery or garden center). It’s coarse enough that drain holes don’t get clogged by it. Put a piece of paper towel or mesh screen (or even a rock) over the hole to prevent soil from falling out. As for pumice, it’s optional. I suggested it because it’s lightweight and helps absorb excess moisture.
Will the plastic bottles an soil work with geraniums?
I don’t see why not. The point is to use less soil and make the pot lighter, and geraniums are not deeply rooted.
Good afternoon. Is it ok to use a large tall planter filled with 100% recycled plastic bottles in order to grow tomatoes? Thank you
Hi Roselyne — Tomatoes have deep roots. I’d be concerned that the bottles would take up too much soil space. Soil also retains water, and tomatoes are much more thirsty than succulents. But I suppose it wouldn’t hurt to give it a try. After all, roots will go around the bottles, just as they would similarly-sized rocks. You can water more often. I’d love to know if you try it and are pleased with the results.
Can I use Oil Dri from the auto store? To replace pumice? can’t find pumice in my area
Hi Vicki — I checked, and Oil Dri is the pretty much the same thing as kitty litter, a clay that absorbs moisture. So, the answer is no. I do wish pumice were more widely sold. For online sources, see the soil page of my site: https://debraleebaldwin.com/pumice/