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.
Can I use washed granite small stone over plastic bottles in pot
Do you mean a gritty decomposed granite? You can use anything you like (it won’t harm the bottles) but that’s not the best soil medium for plants. See my soils page.
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 you use any recyclable plastic bottles or does it have to be water bottles?
Any will do. But if they’ve contained anything edible or sugary, I’d rinse them first.
I tried this method in a plastic whiskey barrel. I used empty water bottles and then just put soil on top. I planted amyrillas . After a few hard rains I noticed the water bottles hat floated to the top. Do I just need to drill more drainage holes in my barrel!?
Hi MM, plastic whiskey barrels don’t come with drain holes? Amazing your amaryllis didn’t rot in soil soup. Yes, all pots that contain living plants need drain holes, unless of course it’s a water garden. I’m glad you mentioned that the plastic bottles are showing. That may happen over time even if the pot isn’t full of water, because soil settles…in which case, simply add more.
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/
I was gifted two VERY large resin outdoor pots. I am thinking of using your idea with the plastic bottles and planting baby’s Breath in them.. What do you think? thanks
Hi Carolyn — I don’t see why not. On the other hand, you don’t say how large VERY large is or what city or region you live in. Moreover I’ve never grown baby’s breath, nor do I know where you plan to put those Volkswagen-sized pots (sun, shade, edge of an embankment?)
Hi – I see you are talking about succulents and am wondering about other plants.
I am making a vegetable garden in containers this year, and have LARGE pots. My tomato plants call for 11″s for the roots. My pots are 22″ deep, can I use the same principal as with the succulents with the water bottles?
Thank you
Hi Beverly — I’m no tomato expert, but I do know they need deep soil. You could partly fill the containers with tightly capped plastic bottles to save on soil and reduce weight, and the roots would find their way around the bottles just as they would around underground rocks. But I’m thinking, soil isn’t THAT expensive, and you want vibrantly strong tomato vines, so why not go ahead and give them rich, deep soil? Treat them to a little composted manure or fish emulsion while you’re at it.
Potting mix is expensive in long run compared to cheap cost of SOIL /and I myself being over65 and doing only container gardening only use the potting MIX for my tomatoes and peppers containers etc. (Soil was always usually added into your holes in the ground growing and yes it’s soooo very heavy etc). I’m going to try some water bottles for a little space in my 5g tomatoes buckets and see how roots do, no pumice either. Hopefully won’t stunt my tomatoe 🍅 plant.
Sounds like a plan. Consider adding dilute fish emulsion when watering to boost fruit production.
You can also cut the bottles in half (capped or not) and use any old plastic container…. Empty yogurt container etc…
Hi Trudy — I’m with you on using other types of plastic containers, but I don’t know about yogurt containers. The lids might come off too easily. That’s why water bottles are ideal, because their caps screw on tight. I also don’t get how cutting the bottles in half, capped or not, would work. The point is to add lightweight objects that act like rocks but don’t weigh anything—think sturdy bubbles. Bottles cut in half not only wouldn’t do that, they might trap dirt and water that could cause roots to rot.
Quick question, should you dry out the plastic water bottles before recapping and using in bottom of planter?
Hi Bonnie — Just shake out any water that’s left. A few remaining drops aren’t going to add weight. Are you concerned the inside of the bottles might get funky over time? No worries if they’re tightly capped.
Thank you, yes “funky” was my concern, I will make sure tightly capped and proceed. Appreciate the information!
You’re most welcome, Bonnie!
Is this something that I can do with my annuals? My planters are 3ft tall. The depth is completely to the bottom of the planter. There is no divider. I’ve tried using a plywood divider with holes drilled in it & it hasn’t worked. I’ve saved enough empty water bottles to fill the planters. However I’m thinking that when I put the soil in that it will just fall through in-between the water bottles to the bottom of the them. The planters are too tall to fill them just with topsoil. The topsoil becomes a sponge & kills my plants every year yet I see people who have tall planters & their annuals are so full & vibrant. I don’t know what the solution is. Thank you.
Hi Chandra-Lynne — You have 3’tall planters you don’t want to fill with soil, but you don’t want to use tightly capped plastic bottles because soil will just fall through the gaps. I don’t see that as a problem—it’s not enough soil to become a sponge. But if you’re concerned about it, cover the bottles with porous lava rock. Then add potting soil to the top fourth of the pot and plant in it. Another idea would be to use a cache-pot, a plastic pot that you wedge down into the larger pot and then plant. So basically you’re using the big pot as a kind of pedestal (but the smaller pot doesn’t show). No bottles needed. One more thought…by definition, annuals die after blooming and need to be replanted, well, annually.
Thank you very much.
Hi Debra, I have a 205 cm length, 60 cm width and 70cm height planter turning up to put two clumping bamboo plants in. I had it made to 70cm height for screening. The planter will be too heavy if filled with soil so I want to add plastic bottles at the bottom. The bamboo roots should only go as deep as 40 or 50 cm. Is there any specific way I should arrange the bottles? And will pumice stone be ok for the bamboo? Any guidance would be much appreciated! Thanks Jenny
Hi Jenny — This isn’t rocket science, dear one. It’s more like rock science: You’re basically filling the bottom of the pot with “rocks” as far as the plant is concerned. Their roots will go ’round them as they would in nature. How you arrange them…well, I like to lay them horizontally, because when vertical, the tops tend to show over time. Of course, that’s fixed by simply adding more soil. One concern might be that your pot would become top-heavy over time, without enough weight to anchor tall plants. As for pumice, well, don’t bamboo plants come from regions with volcanoes? In any case, I can’t see why it would be an issue. (But then I’m not a palm expert.)