Making Soil Blocks


Propagating vegetable plants is possibly the
stage of the growing process that has the greatest diversity of different options of
methods and equipment to that can be use. I’ve tried a lot of different methods for
starting my vegetable plants, including using big trays of modules, growing in individual
pots, transplanting bare rooted plants from a flat of soil or from a dedicated seedbed
in the garden, direct sowing , and I’ve even tried using toilet paper rolls. A few years ago I decided to buy a soil blocker,
which I had been intrigued about for a while, as it seems such an odd and interesting idea,
to simply compress blocks of soil. It turns out that I quite like using this
method, and it seems to fit the scale of the growing that I’m doing, and I’ve adapted
to using soil blocks for quite a bit of the plant propagation for my gardens. The reasons that I like to use soil blocks,
are essentially the same reasons for why this tool was developed how it’s being promoted. I like the fact that it has allowed me to
significantly reduce the diversity and number of plastic trays and pots that I would otherwise
need to use in my gardens, but it hasn’t eliminated plastic altogether, not yet at
least. If done properly, the plants are definitely
less root bound when growing in soil blocks, then they typically get where they are grown
in pots, or modules, or other containers. In a lot of ways there’re easier to manage
and to transplant, if done properly. And they’re quite adaptable, as I can produce
and use as many blocks as I need, rather than having to fill in entire tray with a lot of
seedlings that I wouldn’t use or to have a half empty tray take up a lot of space. Soil blocks are a fairly simple concept and
process, where you use a tool to press a growing medium or compost into blocks, and then the
seeds are planted directly into the to of that block. A lot depends on the nature and characterises
of the growing medium or potting compost that is being used. It apparently needs to be quite fibrous in
order to hold the block together, firm enough so that it doesn’t fall apart when moved around,
but still open enough internally for the roots to be able to penetrate and easily grow to
fill the entire block. I was initially worried that these blocks
would be too firm and that they would restrict the growth of roots but it doesn’t seem
to be a problem, at least not with the prepared mix that I’m currently using. The blocks are made by pressing the blocker
down into the growing medium to pack each of the four moulds of this tool, and then
the lever is squeezed to push the blocks out. The sets of 4 blocks can be placed on a tray,
board or any other kind of surface, and quite a few of them can be made in a relatively
short period of time, even with the small version of this tool. Little plastic dimples in the top of the mould
create an indentation in the soil block that seeds can be planted directly into, and then
they can be managed and cared for in ways similar to most other forms of propagation. It is fascinating and a bit unnerving to see
the roots grow to the surface of the side of the block and then to either stop or start
to grow down the outside of the soil block. A lot of types of plants don’t seem to mind
their roots expose like this, so long as they are reasonably sheltered, and kept moist of
course. When it’s time to transplant them into the
garden, or to pot them up into larger containers, I simply pick up the block and drop it in
the soil. I think the thing that impressed me most was
how well these soil blocks stayed together, most of the time. I find that making soil blocks is a fairly
straight forward and simple thing to do, but as with anything there are a few techniques
and conditions and make things a lot easier. Getting the right amount of water into the
mix before making the blocks really helps, and it seems to work best when the growing
medium is much wetter than I would have expected. I needs to be wet enough to allow the material
to press or flow easily into the mould of the tool, like a soft clay, but without being
so wet that the material falls out again. Once made, I found it easiest to simply drop
the seed, or numerous seeds, into the little indentation into the top of the block, and then
to press them lightly in the block with the top of a pencil, so that they are in direct
contact with the growing material. It seems that most of the time the seeds don’t
need to be covered with anything else, but some types of seedlings seem to benefit from
having a bit of weight of soil on top of them, so that they can root properly. But this may be due to how much the growing
medium was compressed when the blocks were originally made. Watering these blocks is possibly the most
critical issue, and can be a bit tricky as the water can so easily flow through the spaces
between the blocks. Like all methods of propagation, frequent
watering really helps, but once these blocks dry out they can be really difficult to wet
again. This is something I’ve struggled with at
times, and I found that floating the flats in a big tank of water was the best way to
ensure that they were fully watered, right through to the centre of the block
The first season I started making these soil blocks, I used a range of different types
of plastic trays that I had hanging around, in order to place the block into. But then I built a number of different sized
flats or trays out of scrap wood, and I designed them so that the blocks were fairly close
together, that the space between the blocks was quite small. I did this mainly out of a concern to reduce
the amount of water evaporation off of the sides of the soil blocks, but it ended up
increasing the likelihood of the roots of the plants in one block jumping the gap and
into the adjacent block. This undermined the whole benefit of the roots
being air pruned and it did mean that there was occasionally some significant root damage
when I had to pull blocks apart in order to transplant them. I also found that having a closed or flat
bottom meant that the plants sometimes formed a continuous mat of roots at the base of the
blocks. This may have helped the seedlings to grow
quickly but caused problems and substantial root damage when it was time for translating. I’ve recently shifted to using opened bottomed
plastic trays for a lot of the soil blocks, and intentionally spacing them farther apart. This meant that the regular watering became
much more critical, but generally ensures that the roots are pruned at the surface of
each individual block, which is what I want. With these plastic trays I found that the
best way to water the blocks was to simply place the whole tray into another tray lined
with plastic and filled with water, which insures that the whole block becomes wet. This does take time to allow the water to
soak into the blocks, compared to a quick watering with a watering can, but it is much
more effective. Another interesting aspect of this soil block
method is that I can get another tool to create micro blocks, for sowing many plants in a
very small space. These smaller blocks can then be transplant
into the normal size blocks once the seedlings have established. These micro blocks are great for starting
seeds that are really slow to germinate, or when sowing older seeds that have a very low
germination rate. They really do allow a seedlings to be started
in a very small space, but with such a small amount of soil they dry out very quickly and
need to be soaked a least once a day, if not more. The little plastic dimple in top of the standard
soil block can be replaced by an insert that is sized specifically to receive the micro
block, which is really handy. But while they do save space, they also add
another step in the process of propagation, which increases the amount of time and effort
that I need to put in, compared to just sowing into the larger blocks in the first place. And I need to be careful about timing, to
make sure that I transplant these micro blocks into the regular sized blocks before the seedling
roots grow too much. I’ve also found that the larger inserts make
it more difficult to get the soil blocks out of the tool without damaging them. I suspect it has something to do with the
amount of water in the growing medium, the amount of surface tension or suction within
the tool when using these larger inserts. But these are a few issues that I hope to
figure out, as I become more experienced with this variation on the soil block method. Up until now I have been using a pre-prepared
mix or growing medium which I buy in, in order to make these blocks. And now that I’m more comfortable using
this technique, I’d like to start to make my own mix, which would involve experimenting
with different proportions of various types of materials that I can get my hands on, in
order to figure out which works. I’d like to try out a larger version of
the soil blocker which produces many more blocks at one time, in order to increase the
efficiency of this stage of the propagation process, and it would be really interesting
to experiment with making much larger blocks, so that I can continue to transplant larger
plants like tomatoes, rather than having to pot them up into plastic pots. For the diversity of gardens that I have,
this tool makes it much easier to propagate just the number of plants that I need, and
it seems to be really appropriate technology for the scales that I’m operating at. While I still use some other methods of propagation
for different contexts or situations, for now I’m quite content to use the soil blocks
as my main form of for propagating most of the plants in my gardens, and to adapt to
the constraints and benefits of this tool. Well, spring is finally here, and there’s
lots of seeds to sow, and garden beds to prepare, and I’m already working on more videos for
the near future. If you’re new to my channel, and like the
quality of my videos, and are interested in seeing more, I’d really appreciate it if
you would subscribe. And if you’d like to support my RED Gardens
Project, and this YouTube channel even more, I have links to Patreon and PayPal in the
description below. But most importantly, thank you for watching.

100 thoughts on “Making Soil Blocks

  1. Thanks! Interesting video again, on a different subject I was wondering if you have an opinion on companion planting ?

  2. i have been considering getting a soil blocker for a while,i would be interested in your opinion of whether using one promotes better growth of plants before and after transplanting,would the plants be stronger when transplanted for instance so as to be more able to withstand pest and plague.i appreciate your time is precious and hope you have time to answer.thanks in advance

  3. Our local commercial nursery (delfland.co.uk/) uses soil blocks for their tomatoes – and others. I find the system fascinating, but our plot does not really warrant one.
    Perhaps I should take a leaf out of the Swedish Homestead book and make my own.
    Thanks again for a very interesting and timely video.
    Wishing you all success for the coming season.

  4. Way to go Bruce. See if you can get hold of some compressed coir bricks. When you rehydrate that stuff it goes great into a block mix, and makes your premium potting mix go further. Plus I reckon the seedlings don't even know they've been transplanted, and don't skip a beat. I think the tiny ones are best for tricky and really tiny seed – and I just put them straight out – don't bother putting them up a size. Good luck for a gentle, successful season! Great video.

  5. Funny you did this video, I've been looking at this for ages, so I bought a soil blocker set a couple of days ago.
    When I was a student gardener I use soil blocks most the time both for sowing seeds and potting on. A machine made the blocks. Cheers.

  6. Unrelated question, Bruce… how did you stretch so well the plastic film used to cover your polytunnel? It looks as if it was shrink wrapped around the structure!

  7. I might invest. I've been using Nutley 40mm compost pellets which are just brilliant for a couple of hundred plants but a soil blocker might work out cheaper in the long run. I tried coir pellets too but they were so bad it was hard to credit they are sold at all. Dreadful germination rates and yellow leaves on those that did.

  8. how many seedlings do you plant? depending on the amount you might want to look at the "paperpot transplanter". I guess that for the plots of your size the transplanting appliance may be too expensive but there are farmers who use the paperpots to start seedlings and manually transplant (i.e. 8-16 seedlings in one go which is much faster than transplanting individual seedlings, for example: https://www.youtube.com/watch?v=RAwir1-g7mY).

  9. please keep us updated as you come up with better ways to use soil blocks. I've always wanted to use them, but I do all my seed starting indoors and they're hard to keep air pruned properly

  10. Thanks lots. Few thoughts …
    1. you don't have to spend on plastic flats with the soil blocks… but they're relatively cheap anyways. 2. you dont have to figure out proportions of water to soil to make the blocks (unless you really want to)…this is in favour of the ready-made plastic flats. 3. You can't water from above or you risk breaking up the soil block…thats a little more work than just sing the flats..besides you making blocks by using the flats anyways. Just a few thoughts of mine. 4. I've done come to realise that the tinier the seedling spouts are more easily transplanted…so the bigger the seedling the gradually more difficult the adaptation…so a bigger block its necessarily better. They still have to adaptto the new transplanted environment anyways even if they have a good root ball zone. 5. Is using plastic a point high on your list of consideration?.. even if you get rid of plastic flats…you still have a plastic covering on your tunnel house. Plastic is convenient, yes! Many things are. We need to Just be good stewards and not abuse resources

  11. Where you can buy this soil block press in Europe? I tried to Google them in past but withou succes. They Will be nice gadget for next season.

  12. I use a sieved multipurpose compost with perlite about 30% by volume with about 3% fish blood bonemeal and put them in a long tray I got from Dutch manufacturer which has channels, I fill these with water, I can't remember what the manufacturer is called but they are very light and flimsy trays made to hold 84 cell trays which I would not recommend. Anyway, these blocks can last about 6 weeks, which is plenty of growth before transplanting.

  13. I’m an experienced gardener and had never heard of the ‘blocker’ tool that you’ve highlighted so well. Yet another Awesome video mate. I’m constantly being educated watching your videos. Keep em coming. Thank you SO much.

  14. Bruce, when it's more difficult (7:06) to release the bigger blocks with the little block indent inside because of increased surface tension – I'm wondering if it wouldn't help to dip and / or shake the whole tool in a pail of water on a regular basis, and maybe let it drip a second or 2, as a simple way to keep it lubricated and rinse out the soil?

  15. There must be a machinist here who would make him a delrin block with a slight taper to allow easier release of the block ??

  16. This is great for those of us with limited cover space, much better than trying to juggle untold pots and half-empty trays. Too bad they are quite expensive for small scale gardeners – I will try to make a simple wood mould instead.

  17. Regarding watering at 4:10 I wonder if you could use "Flood and Drain"? Might not be viable if your bench is temporary, during plant raising only. Some years ago I considered Flood and Drain vs. Capillary matting, for the whole bench area in my greenhouse, and went with Capillary Matting, tucked into a reservoir along the bench. Whilst it worked well, and better than manual watering, it watered everything the same amount, and was too wet for many things, particularly in the colder months. So I am now going to switch to Flood and Drain. I bought some commercial benches – basically upside down U-tubes for legs, scaffolding poles along the length onto which a lightweight bench-frame sits (and can slide back/forth on the scaffolding poles to "borrow" space from the path). I will arrange it in sections, stepped, so that Flood of top bench can then flow into the next lower section, all the way down to the lowest. I will put the plants requiring least frequent watering at the top, and most-frequent at the bottom, and then I can choose to skip the watering at the top on some days, or flood for "shorter duration". I resent the time it takes to manually stand pots into a tray for bottom watering 🙂

  18. Great video, Bruce! You reminded me I should go press some soil blocks 🙂 I would be very interested in a follow up on making your own potting mix for soil blocks.

  19. very informative. how would coir based medium go and have you used the blocks on heatmat? maybe water crystals (mixed unexpanded) could help the blocks stay moist longer. wind is the ultimate dehumidifier of soil.
    a more elaborate setup with raised flood trays (with plug) connected together, could save you time dunking seedling trays.

  20. Hardly ever have to worry about being too packed. Seriously I grow plants in no tilled clay. The roots will find a way as they start off their growth at the cellular level. The biggest problem is the lack of oxygen which isn’t a worry with these becuz they have no sides made of plastic.

  21. What you need is a wooden tray with dividers for the blocks, 8 × 4 blocks per pray would be plenty, while you're at it make the trays stackable so you can get more of them into less space

  22. Hello sir, I know we had a few differences last summer re water… I just wanted to update you on my own efforts to collect water for my humble garden… I have been collecting water from bottles, jars, pots and other containers .. I have it on good authority that Britain where I live lost 20% of its fruit/veg produce last summer. I am doing my bit. Embracing for impact although Dr Guy mc pherson says it's irriversible and climate change is going to be abrupt in a few years…anyway ……… did you make that pond ? Do you have any thoughts on water? Anyway regards to you and your good efforts..👍

  23. I used soil blocks for 2 seasons and went back to trays because blocks take a lot more time and I saw no benefit whatsoever over just using plastic cell trays.

  24. This is, by far, the best video I have seen on soil blocking! I have the 4" Maxi blocker, too. It uses a little less soil than the 0.7 gallon pots, and the plants seem so much healthier in the blocks. You explain everything so well!

  25. Im gettig ready for fall and now this video appears?
    Im going to save a lot of money and time. Soaking my trays is always good, but it seems that the blocks like it better.

    Thank you. Saludos desde México.

  26. Maybe adding a little bit of coconut fibres to soil mix would reinforce the blocks? I mean few cm long fibres and not that horrible sawdust like stuff.

  27. I have absolutely zero interest in soil blocks, but I knew your video would provide very useful information still yet. Just awesome. Thanks.

  28. When I was an apprentice on a farm, we covered the seeds with vermiculite. Also in Elliot Coleman's book "The New Organic Grower", there is a recipe for soil block mix.

    “30 units brown peat
    ⅛ unit lime
    20 units coarse sand or perlite
    ¾ unit base fertilizer
    10 units soil
    20 units compost”

    and for Mini blocks

    “16 units or 4 gallons (15 l) brown peat
    ⅛ unit or ½ cup (120 ml) colloidal phosphate
    ⅛ unit or ½ cup (120 ml) greensand
    4 units or 1 gallon (3.8 l) well-decomposed compost”

  29. Coco choir, perlite, and vermiculite the mix I used for seedlings. The problem is the mix has no nutrients

  30. One channel I watch, Lumnah Acres, uses soil blocks, and he made his own large block maker as well: https://www.youtube.com/watch?v=W2gs5CxYVrI

  31. Which size of this tool do you recommend I get?
    I see there's 4 sizes available for me.. These are 10.5×10.5cm, 5x5cm, 3,7×3,7cm, 1,8×1,8cm

    I'm thinking the biggest one is not gonna happen, but I'm a bit stuck on either 5×5 + 1,8×1,8 + square insert versus getting just the 3.7×3.7 one.

    My application is small home indoor "gardening", possibly balcony planting.

    Thank you in advance from Norway 🙂

  32. this was a helpful perspective on the soil block. I've had good luck using plastic paint trays with microfiber towels as a capillary mat. While this adds plastic back into the system, the trays are small enough to allow you to selectively control the moisture of different seedlings and the microfiber does not encourage mold like a cotton or some other capillary mats (and they are re-usable and cheap). I set the blocks directly on the microfiber but you could set a mesh bottom tray (like the one you have) on top of a this microfiber capillary mat and simply lift the tray a few times each week to prevent roots from growing into the mat. I use a mix of compost, peat moss, and perlite (or vermiculite) with cotton seed or alfalfa meal fertilizer. I try to time the planting so the seedlings get out into the garden before they outgrow the blocks. (when you start making you own mix you may like the cube inserts, the mini cubes save a lot of germination space on the heat mat and under lights).

  33. This seems like a good one? https://soilblockers.co.uk/dottimabel/soil-blocking-hand-tools/mini-4/

    They even have a recipe;
    Take a two gallon bucket of good fine multi purpose compost and add:-
    6 Handfuls of sharp gritty sand
    4 Handfuls of well rotted homemade compost (fine)
    Mix ingredients together. Add water and stir until the mixture, when squeezed in your hand, holds together like a snowball

  34. This tool seems just the thing to help start plants that don't handle transplanting well.  Do you suppose that it would be possible to drill a small hole through those inserts to relieve the partial vacuum that is likely causing them to stick inside the molds?

  35. The logical and optimizational traits you express while discussing your continual processes of trying to improve the garden is absolutely amazing.

  36. I use two of the blockers and they are a blast to use LOL. I saw a video where someone used a cloth diaper to line the crates and kept in continuously moist by hanging it over the edge into a container of water and I am trying that this year but it's too early to tell. Love this channel. Your newest subscriber, from Ottawa, Canada.

  37. That soil blocker is ingenious. Boggles my mind that they don’t fall apart slowly with each watering. Maybe the roots help with that. In Australia we have ‘Jiffy Pellets’ a 100% peat medium in a biodegradable stocking thing. These are dried and compressed really flat, then at home you expand them in water and plant your seed. They are about 4cm round and tall to make a cylinder. Unfortunately they are $0.50 and I plant 100 tomatoes a season plus capsicum, eggplant and chillies. The soil blocker seems to be a great solution, trade some layout for a cost saving.

    I subscribed and find your videos very interesting.

  38. Park seed co. has an interesting "sponge' material that holds just the correct amount of water without the block becoming utterly sodden. What mix of materials would you suggest to make the blocks used in the video?

  39. I invested recently in soil blockers and I am very impressed with how the process works. The biggest issue I have had is getting a mix that clings together and is viscous enough to avoid blocks that fall apart.

  40. I found that the idea of using a soil blocker was a lot better than the reality. I don't doubt that one can learn to make it work — once you've built the frames to hold them; developed a watering technique; mastered the soil consistency; and developed the right soil mix. But after a while, I just didn't think it was worth it. I'm glad I got to see someone else struggle with it. It will be interesting to see whether RED gardens continues to use one down the line.

  41. It is possible to use earth for the blocks…. what I mean mix somesoil with water and maybe something what can help to fix it ?

  42. I bought a soil blocker this Spring. I had a lot of trouble getting the seed starting mix to form no matter how much or little water. It was very frustrating. Also they didn’t want to release from the blocker very well. Then some fell apart while putting them in place. I hope you or someone can come up with a seed starting mix formula that works good.
    Thanks for your video.

  43. A press for turning shredded paper into fuel logs looks exactly like the kind of thing you could use to make larger planting bricks. A normal brick press would probably make them too tough for the seeds to root properly.

  44. I absolutely love your videos and your presentation of them. You seem very honest, and honesty to me is Paramount.
    I wish you the very best in your gardening Adventures as well as your personal life.
    SUBSCRIBED

  45. I've got the same two blockers, and agree with everything you say here. I'm also curious about the large single block maker (4" maxi) as well as the 35 count 2" blocker. Both are pricey. I'm waiting for a reliable review before shelling out for one or the other. Hint hint.

    I'm not a big fan of the micro blocker due to what you mentioned (additional steps/work), and the soil that I'm using (I've tried 4 different ones) has too many long wood fibers and small twigs. This makes it difficult to form good cubes, and they have a tendency to remain joined at the bottom. I still consider the size useful for seeds with low germination rates, though.

    In my dry Colorado climate, I have issues with dry blocks. I'm looking forward to trying your watering method.

    Thanks for consistently thoughtful and useful content.

  46. This channel is basically gardening made more difficult. Just take something easy and experiment until you find the most difficult method

  47. those tiny blocks are so cute! and them slotting into the bigger block must be super saitsfying to do

  48. Adding a draft angle to the micro block inserts can likely reduce the suction preventing the soil blocks from leaving the tool.

  49. I use misters in a green house with plastic trays on tables, (drainable trays) You can get different heads that determine the spray distance. These are on timers. We hit them with water that's treated with A/B liquid fertilizer and is Ph regulated. It's all automated. From the nutrient injection to the multiphase temperature regulation. It's a bit Overkill. But what I do recommend is misters on timers. What you are doing could be better for a smaller farm though. 🙂

  50. Thank you for sharing this technique. Experimenting different ways to use soil blocks. Very helpful for us to use this tools in an effective way. Hope i can use this tool for my project on my channel. Again thank you very much

  51. Hey Red hope you're well. Soil blocks are awesome but I have stopped using them in favor of fabric pots for seed starts. You still get the air pruning action but it retains water much better. I cannot attest to which method is faster and as with anything it's got its ups and down. The biggest downside for me has probably been with transplanting; if you transplant when a bunch of roots have already grown through the fabric then you end up having to rip them. So for this has not damaged the plant or stunted it's growth, but it does take a bit more time to free the plant from the pot. The smallest sturdy reusable ones I have found are 1/4 gallon but prefer to use the half gallon ones. I wanted to stop using blocks just because it seemed to be taking too long but I'm not even sure fabric pots are faster. Since the fabric pots are bigger than the 2 inch blocks, the plants get much bigger so procrastination is offset considerably. Yes there are bigger blocks but it seems easier to just be able to drop soil into the pot.
    Thanks for the content and Happy Gardening!

  52. I appreciate you sharing your knowledge & experience but IMO biodegradable peat pots are a much simpler & easier managed option than soil blocks for the small scale or occasional gardener. I would be interested in the design of a mold for DIY peat pots that utilizes a combination of cardboard/paper mache & peat.

    As regards keeping the soil blocks separated perhaps putting them on top of a sheet of thickish waste cardboard and inserting cut strips of such cardboard separators between the blocks would minimize the root disturbance & prevent drying out between blocks?

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