do peat pots inhibit root growth?

Hi everyone! I've been raising seedlings in peat pots this year and then dropping them right into the ground when ready. I've noticed they don't seem to be growing as fast once in the ground as past years. I'm curious how long these pots take to break down once they're in the ground and if they actually inhibit growth of the plant. I figured you guys would probably know for sure whether or not they were worth using.

Welcome to permies Leo
I've never used them, but I've come across loads of stories about them not breaking down in the soil and inhibiting root growth.
I scrounge old plastic seedling pots.

I've only used them a few times and usually they are already really soft and half composted by the time I plant them out, so I haven't notcied a particular problem. Maybe try soaking them very thoroughly in water before planting out and then sort of break them up a bit with your hands to give roots a head start?

You have to rip off any part of the peat pot that sticks out above the soil line or it will dry the pot out and keep it from breaking down. I don't like them much.

I highly recommend The PotMaker Turns old newspapers into lil 2.5" pots!


For larger transplants, I use 24/32 ounce yogurt containers: just punch several holes in the bottom and wah-la! We eat a lot of store-bought yogurt, so we have a LOT. If you're careful, they can be reused multiple times

yes, they are really bad at inhibiting root growth, even here in my climate where they will be gone in a year. the best thing to do is rip the peat pot off the seedlings when you plant. then you can use the peat pot remains as mulch.

I have had better luck with regular pots than peat pots- the concept is good but my seedlings dry out too fast and once I put them in the hugelkultur they just don't do well.

Peat pots- issues that come up are roots still circling, they take quite awhile to break down in arid climates, any of the pot sticking up above ground seems to wick moisture out of the soil, explosion of mold that spreads like wild fire if you are using them in trays, needing to babysit them because they dry out- also so they also aren't too wet. I've had some plants that never could get roots through the pot. Compared to others- we had less root development.

Newspaper pots take awhile to make. If you don't make them right, they fall apart before you even get to move them. Using anything to secure them- then has to be removed (as in tape, staples, paper clips, etc.) Some plants take awhile to break through the pots.. some like tomatillos- send roots not just through their pot, but into the ones next to it (in particular if the pots are started in trays.) You can get a gizmo to make the pots.. but it is not necessary as there are methods and means to make them with things you already probably have around the house. There is even an origami way of folding them into square pots (size varies by size of the paper).. it takes awhile to do, but they can be folded flat for storage. Most of the newspaper will decompose.. but you may still have bits at the end of the season. Also edges of the pot will wick moisture up and out of the soil, but not nearly as bad as the peat pots- easier to tear the tops away or just push them down.

There are (cow) manure pots.. I haven't tried them.

Standard plant cell packs & pots... my neighbors & friends unload these on to us every spring.

Then there is also the SIP pots (self-irrigating planter) you can make from plastic bottles. This I have found works really well for me- and frankly these dang bottles are everywhere even though we never really buy them. They don't really inhibit the root growth, easy to pop the plants out (so it can be used repeatedly- just use another cotton ball), I don't have to worry about the soil moisture for days (no need to babysit them daily.) I'm not a fan of growing anything in plastic- but I haven't found anything yet that is better. I get more vertical root growth- which is something we like because then we seem to have to irrigate a lot less. (Our tomato plants are miserable to pull out at the end of the season.. but it paid off during last year's drought. Same style thing.. add fruit juice or something yeasty to the bottom reservoir and it works well as a fruit fly trap.

5 years later, but looks to be the better place to set this.

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I have used a few peat pots  last year and the year before.  By and large, I  recovered most of them.  So I used some of those pots this year, to try and get corn a head start here.  And in some circumstances sunflower, which never does well here, as bambi thinks it is lunch (breakfast, dinner, snack).

This year, I started a new garden area (not enough planning), it was supposed to be a three sisters plot, but one a slightly larger scale (15x20 feet?).  I had too many days of too much wind, and most of the corn plants didn't survive.  I think out of 76 plants, I had 5 or 6 survive.  And this was mostly a wind problem.  It was slightly protected from bambi, and bambi only came int here 2 or 3 times from what I can tell.

I had a killing frost a few days ago, and so after harvesting some things (potatoes, squash, peas), I could do some other examining.  The corn had died too.  It just didn't show it as easily as the squash.  I dug up a corn plant (in a peat pot). Not any corn plant, the biggest corn plant I had.  The corn plant had "broken through" the bottom, I seen no evidence of a bottom existing.  But the sides were still all well and good.

(I'm at 56N, things like killing frost happen early here.  My forecast for Tuesday night is -3C with snow.  (This is Saturday.))

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There are alternatives to peat pots.  But for me, the question is are they biodegradable?

I had heard of Cow Pots, and looked into them.  Sure, they started from cow manure.  But what they seem to have done is to wash out, or clean, anything that isn't "fibre" from the manure.  And then they go to make a pot.  So it really isn't a Cow Pot, it is a fibre pot.  And I would suspect if one goes looking into peat pots, you might find something similar.

Lots of people don't like things to smell.  So, a manufacturer will do things to make it smell less (or not at all).  I think a side effect they see, is that the pot has a longer shelf life.  For just about any business, a long shelf life is good.  For a supposedly biodegradable product, a long shelf life is probably not what you want.\

Looking further into things, I ran across a web article about making paper from manure.  And basically the manure was processed to the point where there was no more smelly organic matter left, it was just 100% fibre.  And of course, they were able to make paper from it.  There are scientific papers on making paper from manure, but they all follow the same path, get everything smelly out, and what you are left with is basically pure fibre.

I ran across one web report of someone making pots from cow manure, who did not go to all the steps to remove everything that might smell.  And she got pots which worked.

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If you are looking for biodegradable pots, look into the shelf life of the pots.  If the shelf life is more than 1 year, they are not biodegradable enough to be used for potting plants.

I think the biodegradability of pots from material like manure (cows or other farm animals) is a function of processing.  If it still smells, it may degrade before the end of the season.

You do need to plant these pots about even with the surrounding soil., so that moisture isn't wicked up and lost before it can participate in degradation of the pot.


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Dietary fibre is more or less a polymer of sugar (some kind of sugar, not necessary dextrose), that is some moderate length long.

Starch is a polymer of sugar, that also has some range of lengths.  It could overlap with dietary fibre.

Cellulose is a polymer of sugar, that is much longer than starch.

I believe the longest cellulose fibres are from the flax plant (not trees, which are actually quite short compared to flax).

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The food industry has had a product called "partially hydrolyzed starch" (PHS) for a long time.  I used to be involved in athletic first aid, and where I ran into this is that PHS may not need to be "digested".  It can just pass across the wall of the GIT as is.  Where I first seen PHS when I went looking for it, was in the baby food section.

PHS is long enough that an insulin response may not be seen.

Two things.  Sometimes seeds are too small.  So you want to "make a seed bigger" by coating it with something.  Quite often, the something is "dextran", a PHS (based on dextrose) usually from corn.  Dextran is often used in making pyrotechnics.

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I think to make biodegradable pots, you can start from many starting materials.  You DO NOT want to reduce the product to fibre!  To be biodegradable, the material needs to be food for bacteria/fungi.  Which means shelf life will not be long.  Preferably less than 1 year.

Sorry, I don't have the URL for the person (lady?) who made pots from cow manure without removing anything.

Try making pots from whatever manure you have available.  If they don't seem to work out, the thing to look at to make things better, is probably make dextran.  The pyrotechnics industry has recipes for it, it is just roasted corn starch.  Add as little dextran as you need to, to get a pot which works.

I just rip off the bottom as I plant, better safe than sorry Throw the removed part in the garden to decompose or be a mulch, whatever it chooses

I have had a problem where I thought it was preventing the plant from rooting in the soil. I just read where you should tear about an inch from the top of the peat pot and about the same from the bottom.
I’m going to try that next. Hope it works and hope this helps

Leo asked, "I'm curious how long these pots take to break down once they're in the ground

Years!  I run across remnants of the pots even after 5 years.  This may have something to do with soil conditions, annual rainfall, etc.

By removing the bottoms of the pots, as recommended, this will allow the roots to grow into the soil and not stay bound in the pot.

I am less than happy with them.  I have learned to remove the entire pot.  I am moving away from using the things.

Everyone in this thread is worried about the biodegradability of the pots -

Here is my main priority- will cow manure composted pots not let the root zone dry back? And will this ultimately stunt root development? I’ve used solo cup method for years with no problem but am thinking about starting some very expensive canabis seeds with them.

I've used them for years. They decompose real fast in The Roots will grow right through them. This year I've got Roots growing through them before I even get them in the ground. I think they work great.

I absolutely despise peat pots. I always end up having to peel them off the plant/soil. I've tried using them in my grow shelves, and they just get slimy and disgusting. It's been my experience that the plant roots just won't grow through the darned things. My husband bought a bunch, and I had to ask him never to buy them again. The ones I have used, I peel them off the plant, bust them up into little pieces, and put them in my potting soil. I have better luck with crappy potting soil with too much wood products in them than I have trying to start plants in peat pots.

Short answer, no.

Longer answer, yes, only if  you let them get dry.

Maya Rapp wrote:I absolutely despise peat pots. I always end up having to peel them off the plant/soil. I've tried using them in my grow shelves, and they just get slimy and disgusting. It's been my experience that the plant roots just won't grow through the darned things. My husband bought a bunch, and I had to ask him never to buy them again. The ones I have used, I peel them off the plant, bust them up into little pieces, and put them in my potting soil. I have better luck with crappy potting soil with too much wood products in them than I have trying to start plants in peat pots.

I kind of agree and disagree.  They do have a tendency to fall apart if they are too wet, especially when it comes time to handle them.  If they are slimy, there is something else going on.  Now a days, many peat pots are paper pots sold as peat pots, so you have to watch out for that.  I'm 60 and have never encountered a slimy peat pot, wet and cool, yes, slimy, never.  Letting the pots dry a little before you water again is helpful because the dried pot "air prunes" the roots and the roots will not penetrate most of the time due to the lack of water.  Planting in peat pots a little bigger than you think is necessary is also a good idea because it allows for more root growth.  I think the plastic potting trays are a lot easier to handle but they are not as plant friendly, especially if the plants are left in them too long before transplanting which results in root binding.  Its all give and take, so don't despair.