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How to Make a Soil Plug Tool

One of the best things about running this blog and podcast, is the cool creations I am shown by listeners and gardening friends. ( Click on the Photo to see a larger version of the photo)

Soil Block Maker

Homemade Soil Block Tool

After talking about peat pots and making pots from newspaper, my friend and listener Tony M. showed me his homemade soil block maker.

Now many of you may not think its such a big deal.  After all, you can just buy one online for not too much cash.  But reusing and recycling is also a big thing to me, and when Tony shared this with me I knew I would have to share it with you.

The major components of this tool are:

  1. PVC Pipe section the diameter you want your Blocks ( 2 or 3 inch )
  2. a Bolt longer than the length of the PVC and the Soil block length
  3. A Nut for the Bolt
  4. Section of wood cut with a Hole saw crating a plug ( Optional)

The wood plug is optional but does make the tool work more smoothly.

Soil Block Medium

Push Device into Prepared Medium

Once you have created the tool, take a plastic tub of whatever size happens to be convenient for you, and mix some of the Seed Starting Soil with some water.  Don’t make it muddy, just enough to make things stick together.

I use commercial seed starting mix so I can be certain it’s sterile.  Newly emerging plants are very susceptible to bacteria and diseases, so this is one area I do buy commercial mixes.

Once the medium has been mixed up, use the tool as a Cookie Cutter in the soil.  Moving over to the seed tray or tub where you will be keeping your soil blocks, use the bolt in the PVC as a plunger pushing the soil out into the tub in a neat little block.  notice the Bolt and nut on the end have even created a little dimple for you to plant the seeds into.

Soil Blocks in Tub

Push Soil Block into Tub

Repeat for as many blocks as you want to make.

Soil block are such a great way to start seed as there is no plastic, cardboard, or other waste as would be typical from most commercial seed pots.   I have even had mixed results with peat pots in the past.  I was so uneasy with them I would dampen them before planting and tear them open just before planting.

Don’t forget that without seed pots you have less expense and waste each year too.

Try some soil blocks.  I think you may like the results.


Soil Block Tud

Soil Blocks in the Grow Tub

{ 13 comments… add one }

  • ROBERT HILL February 8, 2015, 5:46 pm


  • Suzi February 12, 2014, 9:46 pm


    For seed blocks to put transplants into, could you use several nuts on the end of the bolt (about the same size as the “micro cylinder”) to make the space for the transplants?


    • Steve February 18, 2014, 4:26 pm

      Sorry I took so long to reply, Suzi. Yes, of course you can use additional nuts. And if they don’t provide a large enough diameter, just add a washer or two of the diameter you want.

  • Mike January 18, 2014, 9:29 am

    Hi Steve – Thanks for the no-nonsense guide for a DIY soil blocker! I’ve also been balking at the price for a “real” one, but most of the DIY plans I’ve seen seemed unnecessarily high-tech.

    One question I’ve had with every DIY blocker I’ve looked at – how do you determine the degree to which the soil gets compressed? I imagine that if you under-do it, it falls apart, but if you over-do it, the roots have trouble penetrating and don’t get any oxygen. If you have any insights on pre- versus post-soil volume I would really appreciate it! Have a good one.


    • Steve January 22, 2014, 3:47 pm

      Hi Mike –
      Gosh, don’t really know how to answer this one. There isn’t any formula or measurement as to how packed to make the blocks. They should be moist enough to hold together when pushed out.

      If not, add more soil to the batch and try again.

      I have never had problems with packing to tight. By the time of the first set of real leaves shows up, I either transplant or upsize by planting into a larger soil block. It has always worked fine and no plants starved for oxygen as far as I know from the process.

      That’s about it. Good Luck

  • Asha October 3, 2013, 5:47 pm

    Hi Steve,

    Thanks for this DIY page! I am interested in using these on a market garden scale, but wondered if you could share any experience with watering these blocks? It seems like when you first water it, the soil will run off or the seed will be displaced. And later when it is rootbound, the roots will dry out much more quickly than if they are in a plastic tray.
    Any thoughts?

    Thanks again!

    • Steve October 3, 2013, 5:56 pm

      Hi Asha –
      I always water the container the completed soil blocks are in or use a mister. I never water from the top. The way these work, the water is pulled upward into the soil block, and capillary action.

      They work wonderfully and these (soil blocks) are the way most commercial growers start their seeds for the upcoming season.

      Are you prepping for a Fall/Winter Growing season? I am and I am surprised at how many people “shut” down until next Spring.

  • Mark Nofsinger February 17, 2013, 2:05 pm

    Love it. Every time I look at the commercial ones I balk at the price–I’m a total cheapskate. One question, though. How do you get an even amount of mix in each block?

    • Steve February 17, 2013, 7:33 pm

      The soil block size depends on the size of the cutter. As for the homemade version, the larger the PVC pipe, the larger the cube will be. Just mix a little water with your soil mix, not enough to be muddy, just enough to hold it together ( same as a commercial block tool). Size is up to you.

      If you start with a small soil block, you can always “plant up” when they get larger which is nothing more than putting the smaller soil cube into the center of a larger soil cube. Works quite nicely.

  • stenerson April 30, 2012, 6:26 pm


  • Mil February 13, 2012, 9:59 pm

    Hi Steve,
    Cool tool. I’ve been using these non-peat moss pellets made by Planters Pride. We just decided to try them after some neighbors across the street told us about them. I was worried about how biodegradable the pellets’ outside would be, and decided when I transplanted outdoors that I would carefully cut the cloth outside so the roots wouldn’t be bound.

    But this sounds cheaper!

  • Mark February 7, 2012, 6:10 pm

    Steve, can you add the keywords “soil blocker”, “soil blocker maker” and “soil cube tool” so that this informative page comes up when Googling for these common terms. Thanks

    • Steve February 7, 2012, 6:30 pm

      Thanks for the reminder, Mark.

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