Honeycomb PVC Planters




Introduction: Honeycomb PVC Planters

About: If a tree falls in the woods...make things!

This project started...about 4 years ago. Five years ago I was buying those little expandable peat moss pucks and muttering that there had to be a cheaper way. Since I try to go 'large and in charge' with my 3 large gardens, and I'm not blessed to live in a coastal state where throwing a tomato seed into the ground will yield fruitful results, starting my seeds before the frost date is a must.

But buying disposable plastic trays year after year and pucks that leave behind a mesh in my garden (to be fair, they do biodegrade) is such a waste of money. Instead, I used my hardware academy knowledge and skipped the pucks in aisle 4, opting to go to the plumbing section in aisle 15. I came up with something so incredibly simple, so incredibly useful that now each year I purposely go back to aisle 4 just to get a good laugh at the price increases I'm avoiding!

What's really nice about this honeycomb planter is that I can get 111 plants out of each one. Since I usually do about 80 tomato plants a year, it gives me a good start and extra's if some of them get bitten off by bunnies (oh those rascals!!). I do about the same in peppers and have even had fun with a large sunflower garden. These things are fantastic for large gardens!

Step 1: Gather Materials / Tools Needed and Used

Material List

  • (2) 1"x10' PVC Plain End Pressure Pipe SDR 21 (Make sure the outside diameter of the pipe is 1 5/16")
  • (2) 1 1/2" x 14 1/4" x 1/2" pieces of scrap wood (more detail in step 3, read that step before you buy!)
  • (2) 1 1/2" x 13 11/16" x 1/2" pieces of scrap wood (more detail in step 3, read that step before you buy!)
  • 14 3/4" x 14 1/4" piece of scrap plywood (or cardboard)
  • PVC Purple Primer (clear works just as good): https://amzn.to/2JY4dlW
  • PVC Cement (Large because you'll use a lot of this stuff!): https://amzn.to/2SMm1na
  • #8 x 1" screws: https://amzn.to/2SJBxQD
  • Nails: https://amzn.to/2MsJM26
  • Potting Soil

Tools Used

  • Miter saw (a hand saw will work just as well)
  • Table saw (a hand saw will work)
  • Pneumatic stapler (a hammer will work just fine)
  • Hand drill
  • Rubber gloves...and you'll use a lot of them
  • Clamps (optional)
  • Block of square wood (optional)

As an amazon associate I earn from qualifying purchases.

Step 2: Cutting the Pipes

This has to be the most difficult part of the entire build, if only because it is a long, tiring process. If you have a miter saw, you're much better off in the long rung. Otherwise you'll have to measure out each 2" section of pipe and cut that section with a hand saw. That's 120 cuts. But before anyone complains about making 120 cuts, I will add that I made 5 of these trays at one time...600 cuts!

Before you start cutting these, MAKE SURE you have the right size pvc pipes. I DID say to use 1" x 10' of pvc pipes (2 of them), but due to schedule thicknesses...and whatever crazy things they do down at the PVC plant, make sure the outside diameter is 1 5/16". I might just be over cautious here, but I really don't want you to have a problem with this project (I love you all, I really do!).

Instead of measuring each section before putting it on the miter saw, I instead made a 'stop block'* at the exact place where my miter saw would cut the 2" I needed. I added a clamp with only a slight amount of pressure and used a piece of scrap wood to hold the cut off down until the saw was completely off. And this is key! Make sure the blade stops spinning before bringing the miter saw back up as the carbide teeth on the blade will catch on the pipe, causing it to go airborne.

Now, as I mentioned in the beginning, each planter will make 111 cells. Why not just stop at 111 cuts? If all goes well, you may stop at the 111 cuts. Due to any error along the way I chose 120 cuts as a general guide.

Cutting the PVC pipes to shape.

* A stop block is a piece of wood that has been clamped to the fence of your miter saw. As you cut material, you'll basically butt the material up against the block making repeatability easy.

Step 3: Making a Box

It is absolutely CRITICAL that you have these 2 things in order:

  1. The PVC pipe must have an outside diameter of 1 5/16"
  2. The inside of the box must have an inside parameter of 13 1/4" x 13 11/16" (13 3/4" will work but it's not quite as snug)

The 2 dimension I gave you for the walls of the box you are about to make are:

  1. (2) 1 1/2" x 13 11/16" x 1/2" pieces of scrap wood
  2. (2) 1 1/2" x 14 1/4" x 1/2" pieces of scrap wood

These dimensions will give you exactly what we are looking for. BUT, they don't have to be these exact dimensions if you don't own a table saw. You could very easily make this out of 2x4's. Heck, you could make it out of plastic (I have 5 boxes made out of plastic), Styrofoam (as long as you don't get the primer on it), branches, sticks, concrete...okay, I'm going overboard here. You can make the walls on this box literally ANYTHING so long as the inside parameter of the box is exactly 13 1/4" x 13 11/16".

For example, if I don't have 1/2" thick boards and chose to go with 2x4's instead (which are generally 1 1/2" thick), my box would look like example A, included in this step. But no matter what (he's going to say it, isn't he), the inside of the box must be 13 1/4" x 13 11/16".

I've also made the wall width 1 1/2" tall, but only so that it's easy to pull the honeycomb PVC pipe collection out after it has been glued together. So again, there's a little flexibility there.

I screwed the walls together and used a square block of wood with clamps to get my 90 degree angle. If you have 90 degree angle clamps or are good about butting wood up next to another piece of wood and getting a good 90 degrees, then you don't need the block of wood or clamps.

Next I added a piece of scrap plywood on the back of my box. Again, thickness doesn't matter. This backing is only to keep our pieces flat. In fact, you could probably get away with cardboard. In the video you'll see that I used a pneumatic stapler to hold the backing on, but if you have time and don't want to use nails, use a little wood glue!

Building the box.

Step 4: Making a Honeycomb (Part 1: Priming)

This part is very easy...and kind of fun (if...you're the kind of person that loves the honeycomb pattern and things fitting togeth...oh nevermind).

You're going to place a row of PVC pipes down along one edge of the box. You'll know which side of the box that row is supposed to go as it will fit perfectly only on one of the inside walls. In the video you'll see that I screwed it up the first time and had to reposition them. I could have deleted that part out of the clip...but honestly I figured it was a good example to show how it fits only one way. No really.

First and foremost, make sure that you are in a well ventilated area, or outside. You do not want to expose yourself to these fumes because they can make you sick. Masks and ventilators, in my opinion, are a waste. Taking these things outside is your safest bet. You'll also want rubber gloves...and a bunch of them as the acetone will eat through the gloves as you are working with it. I'm not sensitive to the actual primer but the purple primers will also stain your hands pretty badly. And trust me, I don't look good in purple.

Each of those PVC pipes will now need to be primed. I used a purple primer because that's all I had in my garage. They make a clear one that will work just as well (and you can see that the last one I made I used a clear primer). So why do they make purple primer? Excellent question! It's actually the next detail I was going to share with you. Just as in plumbing you want each connecting piece to be cleaned of grime, oils, dirt...you will want your new PVC planter to be just as clean. The purple is just an indicator to show our human eyes that that area has been cleaned and, well, primed. And don't try to cheap this one, it's very important to use a primer as it also helps the glue to adhere to it!

Okay, so we'll need to clean each piece with primer. Make sure that after you have primed the piece that you try not to touch those PVC pipes with your bare hands as much as possible as you will be returning glue to the pipes (doy). Set them off to the side, standing up.

Priming the pipe.

Step 5: Making a Honeycomb (Part 2: Cementing)

Now that we know which position the box should be for us to add our rows (back in part one of this two part process...or the previous step), we are going to line the PVC pipes in a row. After these primed pipes are in a row, we'll slather a good amount of cement on the top of them. After they have a good full coating, we'll quickly add the next layer, which will sit on the diagonals of the previous row...you know, honeycomb shaped. From here, we'll add another layer of cement and repeat the process. It's very important to note here that the row below is actually getting the better part of the glue treatment.

Once you have filled up your box from top to bottom, you're going to let it sit there for about 30 minutes. This is not the full cure time for these little pipes, just a good time to remove them. We are not done!

Carefully remove your PVC pipe assimilated conglomeration from its square box by removing the walls or just sliding it out carefully. If you went with the 1 1/2" wide walls it should very easily pull out. If your walls are larger, they'll probably have to be disassembled. Now there might be glued that has adhered to the pipes and whatever materials you used to make the box. Do not despair! It should still come off with a little bit of pulling. Use a butter knife put pull it off...it really doesn't stick well to anything other than PVC pipes, and PVC pipes that have been primed.

Cementing the buggars together.

After it has been pulled out, you're still not done. Each side of your new honeycombed area needs a nice layer of cement. Give it a nice thick coating of glue before setting it aside again, and allowing the entire thing to cure for a few hours.

Before you go and pull out a bag of potting soil...WAIT! These planters are NOT ready yet!!

Step 6: Preparing Your Planters

Before you go and pull out a bag of potting soil...WAIT! These planters are NOT ready yet!! There is still the huge step of cleaning and making sure that it is safe for your soil and seeds. Using a sink full of water, submerge the honeycomb PVC pipes in it and add some soap. Scrub the top and bottoms of each side (there's 6 sides in all). You may run a cloth through each and every hole, but tossing it into the dishwasher and giving it a good cleaning should do the trick pretty well.

Once it has been cleaned well, let it dry. After it has dried, place the honeycomb on a flat surface, preferably outside on a table or concrete. Cover the entire thing with potting soil. Using your fingers, press the soil into each and every hole, packing down the soil as much as you can. Dump more soil on top of that, and repeat. When you've filled them all up to the top...DON'T lift it up! Now it's time to glue the soil together by adding water, which will have to be done in cycles as the water will not permeate the soil right away.

So turn on the TV, mow the grass...whatever you have to do, and come back with a watering can every 10 minutes or so and add water. When it starts to seep out the bottom, you know you're ready. Time to add the seeds.

Preparing the soil.

You'll put seeds on the top of each hole and then compress them downwards. When you've finished with a row or the entire thing, cover the top again with soil and add more water to the top. It is preferable that you don't move the honeycomb around a whole lot...so finding a plastic sheet you can put on the bottom (like a larger, thick cutting board) would be preferable if you plan on moving them around a lot.


When it's time to plant these guys, all that's needed is to push them up through the bottom. Because the roots have grown through the soil, they're a nice compact little bulb just waiting to be planted.

And...you're done!

Please, though, read the next step as it will save you heartache in the years to come.

Step 7: Precautions and Care

These planters are insanely resilient. In the video, you can see that I was able to lift the entire thing up with 1 cell. Okay, well maybe I had already planted half of them, but it is strong enough to withstand the abuse. Cemented PVC pipe is incredibly strong. So when I talk about precautions, I'm not exactly talking about precautions for the actual honeycomb PVC planter itself...in other words, I'm not afraid it'll break.

What I am cautioning you is to be VERY careful about using them year after year. Oh, you can definitely use them every year, but you MUST clean them very carefully. Before I get into cleaning it, I'd like to give you a little history of these honeycomb planters.

  • First year was absolutely brilliant. No problems at all. I had 111 cells and every single one of them--5 of them!--came out great. We did sunflower seeds, tomatoes, peppers...I had hundreds of plants that came out healthy.
  • Second year was hit or miss. I had some plants die, a lot that lived. Very discouraging.
  • Third year was a complete failure. I think I lost every single plant. I replanted but had the same disastrous problem the second planting. That added to the problem with rabbits destroying every plant on the ground almost made me want to quit gardening.
  • Fourth year, this year, I didn't have any problems. No casualties.

So what did happened between year 1 and year 4? Why were years 2 and 3 so bad? Two painful words: Damping disease. It is an incredibly devastating disease that will kill every single one of your plants. Once you find it with one plant, there's a good chance that every plant after that will die or have problems.

So what do you do? After every year you are done with the honeycomb, you have to disinfect the crap out of it. I'm not talking dish soap, I'm talking bleach. And I mean a cup of bleach with a sinkful of water. Pathogens will form after each year of use and those pathogens need to be destroyed.

But it's more than that. Using a good bleach solution in your watering can is also a good idea at the end of the year.

Damping disease is bad, but you can control it. Damping disease is present in the soil but your new plants will be strong enough after you've raised them to have strong stems.

That PVC honeycomb is more than strong enough when it comes to the bleach, so don't be afraid to use it. Allow it to soak in a good solution and then run it through the dishwasher. If you're paranoid like me you'll do it at the end of the year and the beginning of the next...just in case you forgot to do it the year before.

I also don't recommend leaving it outside in the rain. Instead, when it's time to water your plants, find a large enough tupperware container and water from the bottom up by submerging it about half way up the bottom of the pipes (something that this potting system does very well). Allow the top of the soil to stay dry.

If you must water from the top down, use a solution of 1 teaspoon hydrogen peroxide to 2 cups of water. Some websites will talk about using a mix of spices to add to the top of the soil...but what really worked for me was making sure to sanitize and care for my seeds in the way that I have written. These are your babies...you must take care of them!

The damping disease fungus is the number 1 failure for seedlings. Watering on the top of the surface will feed the fungus, which is why water from the bottom up is the preferred method. Of course, when you first start out, as long as you've sanitized it, you shouldn't need to worry about the initial water that I spoke of in the last step.

Step 8: And...You're Done!

Thank you for looking at this instructable! This has been one of my top secret ideas for growing a large garden and putting this in the public domain is a bit of a nail biter for me, but this is my favorite way to grow a large garden.

If you have any questions, please ask them in the comments. Follow me here if you like my witty (ha!) writing. I also love feedback...so don't afraid to yell something at me!

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3 years ago

This is such a clever idea for starting loads of seeds!


Reply 3 years ago

Thank you Jessy, it's been kind of my secret to growing large gardens now for a while. I hope others can find it as useful as I have!