Some plants have extensive root systems and require large pots filled with quality potting soil. Think tomatoes or a Meyer lemon tree on the patio. Other plant roots are not as expansive and just use the top third of the soil. Summer annuals like marigolds and petunias fall into this category, as do vegetables like carrots, radishes, and even beets.
Given the cost of good potting soil, you might think that filling larger containers with potting soil is a waste of soil and money. Since you are not the first to think of this, it will come as no surprise that gardeners have found hacks to fill planters and grow a container garden on a budget Yes, you can fill the bottom half of plant pots with different materials – and here are some options for you that won’t sacrifice the health and beauty of your plants.
How deep is too deep?
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Plant containers they are far from typical. I have tiny plastic plant pots, larger, regular, large, and jumbo. There are half barrel sizes as well as many decorative pots for use with indoor plants. One of my most elegant indoor pots sits on the floor and is as tall as the dining room table. (Large pots might be cool!)
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Many plant containers are intended for plants with roots that fill them. But some clearly aren’t – like my oversized, decorative pot. A pot is the perfect size if the mature roots are just a few inches less than the soil depth. Any deeper, and you’re wasting expensive soil.
Filling the Void
The plant will not be affected (or damaged) if you fill the bottom of a very deep container with anything other than potting soil. There is no “best” filler, so let’s examine it cheaper filling options.
While it is important that the material you choose is free – or nearly so! – some other factors are at play. You also need a filler that allows drainage and it’s not too heavy. You also want to be sure that nothing toxic is added to the pots.
Plant pot fillers
There are many substances that fit these qualifications to serve as container fillers. Here are a few to get you started.
Go Natural
Many of us prefer to use natural materials for our pots rather than using plastic or manufactured materials. If you’re a natural gardener, try one of these fillers.
1. Larvae
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One of the big advantages of using filler material instead of soil in the bottom of extra large planters is weight. A large pot filled with soil is heavy to lift, and moving an oversized decorative planter filled with soil can require two people.
Filling the bottom half of the container with pine cones significantly reduces the weight of the pot. Pine cones resist mold and cost nothing – if you have, or can access, a pine tree. They are completely natural and allow great drainage.
2. Peanut shells
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Who doesn’t love shelling and nibbling on peanuts? Just save these shells and you’ll have a great, natural filler for your planters. Although perhaps a bit heavier than pine cones, peanut shells they are lighter than soil and will cost you nothing.
Peanut shells actually make your soil bettersince they break up the compacted areas and create air pockets in the soil, creating extra space for the plant’s roots.
3. Coco Coir
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Coconut palm is a material made entirely of fibrous parts of coconuts. Often used for hanging baskets because it can absorb water and then release it to the plant in regular doses, preventing overwatering.
Why not use coconut as a casserole filling as well? It also resists fungi and is neutral pHso it will serve well for most plants. If you have old baskets or can get some from your friends, this filler is free. Even buying new coco material won’t break the bank. Organic coconut from Back to the Roots can be purchased from Amazon. A solid brick becomes more than 2 cubic feet of coir when you add water to it!
A use for plastic
Plastic has become a dirty word in modern times, but these man-made materials can be perfect for pot fillers. See what you should use.
4. Packing peanuts
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These aren’t natural like peanut shells, but they’re free and light – and usually end up in the trash. But they’re great as space fillers in planter pots – as long as they’re the type of styrofoam that doesn’t break down in water. Obviously, if they do, your plants will – sooner or later – sink and fall over. Test it first by dropping some in a bucket of water for a few days.
Assuming they don’t, use it Styrofoam packing peanuts to fill the bottom of the container. This is what I used in mine indoor decorative potsmaking them so much lighter to move around when I sweep.
5. Plastic bottles
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Yes, you can throw empty plastic bottles at the city recycling center, but you have no guarantee that anything good will come out of it. Instead, you can fill your containers with these lightweight products.
These “fillers” are just as free as packing peanuts and you’re going to throw them away anyway. You will need fewer plastic bottles than packing peanuts. Just start throwing them into the space and it will soon fill up.
6. Nursery pots
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Do you store your empty plastic pots by stacking them, the largest one at the bottom, in your garage or garden shed? I do, and many of them will never get used to it again. But these make excellent fillers in oversized plant containers.
Instead of crushing them like you do for plastic bottles, plastic plant pots can be used whole. Place the large ones upside down in the bottom of the container – it raises the “floor” of the container, while not adding much weight.
Shop for container gardening essentials
Pure Garden Lattice Design Outdoor Planter Box
Place your plant in a smaller container and drop it into this soil-saving decorative box.
This is my favorite potting mix for strong growth and big blooms all summer long.
Burpee All Purpose Granular Organic Food
Give potted plants a boost with this all-purpose organic fertilizer from Burpee.
