Parboiled Rice Hulls as Alternative to Perlite - PBH

[BrooklynMatty]

So i want to put a discussion out here that i don't think has been discussed at all; Rice Hulls.

The subject came up in my need to start purchasing more ingredients for my medium for the spring, i have many plants to up pot into 10-15g. Last year i was using 5-1-1 and my use of perlite was not enjoyable, i got a big 4cu ft bag from agway which we all know was labeled coarse but was super dusty and i probably inhaled ALOT(not good for your lungs=cancer). I get monthly mailings from AM Leonard as you guys know and they finally offered parboiled rice hulls is small amounts compressed 4cu ft (which is 7cu ft) for $8 which is DIRT CHEAP compared to Perlite, its not free shipping though ( i did email to see if they could make an exception). http://www.amleo.com/rice-hull-bale-7-cu-ft/p/RHB7/


In all my research i have found many things for pros/cons in rice hulls and wanted to bring the discussion to the group and my bud who is the "Medium Master" AscPete since he experiments with a lot of items.

Pros:

• Cheap
• Cheap
• Inert and organic
• Controls fungus gnats if topdressed with 1-2"
• aids in aeration
• and did i forget Cheap!

Cons:

• Hard to source
• Will break down over time, most likely every 2 years
• Possibility that it ties up nitrogen, so you need to account for that (EDIT - Does not Tie up nitrogen)

I spoke to a manager at griffens nursery who sell it in skids, and he offered selling me one as a tester. So i might try it out, might as well order some other stuff since its about 3hr round trip.

[Fygmalion]

I am with you on the perlite.... Breathing that dust is no good. I always wear a particle mask but it really doesn't do the trick as well as I would like. Also, during up potting, even the perlite at the bottom of the rooted cutting can be undesirable to work with. A good alternative to Perlite as far as breathing and cost is concerned would be great!

[BrooklynMatty]

Agreed. I have a great particle mask, but only got it later in the season after i got a miticide.

[Rewton]

I try to always work with perlite using a mask and outdoors if at all possible. I try to stay downwind.

[BrooklynMatty]

Wetting down the perlite in the bag helps too, but then the bag weighs a metric ton - even with holes on the bottom.

[Bluemalibu]

This study, replacing Perlite/peat moss in up to a 50/50 mix, with Rice hull/peat moss produced identical results. When the peat moss was replaced by ground rice hulls, (Perlite/rice hull mix) they showed a 12% reduction in productivity. So, it looks promising for a Perlite substitution. (And, rice milling is conducted just seven miles from me, supporting the thousands of acres of Rice produced in our valley. I hate it when that happens! ;-)

http://www.riceland.com/uploads/pages/purdue_article_2.pdf

[Fygmalion]

Sounds to me like another positive affirmation on your choice of living locales... :-)

[BrooklynMatty]

lucky schmuck. Cali is one of the main rice producing states, you should definitely test it out.

[Fygmalion]

And I oh so love rice pudding....

[CliffH]

If you are in areas that commercially grow chickens, you might check supply sources for this industry. When I was younger, we used rice hulls to cover the floor of all our commercial growing house (we raised 20,000 chickens at a time back then). Made great fertilizer when we sold off the chickens too. Our hay fields were some of the greenest around.

You might have to clean hulls sources like this some to used in a potting mixture. But it would possibly be a source many people might not think about.

[BrooklynMatty]

I personally dont have any near me, i checked agway's site and they dont have it. But parboiled is what people want since its weed free

[dkirtexas]

I recently started a thread on the "Other" Forum and did not get a lot of response. There are several Rice Mills in the Texas/Louisiana/Arkansas area and I have a list that I will pursue as soon as possible. The soil/media industry appears to buy most of the available market. I am sure that at the distributor level the price may be higher than desired.

I did not find any negatives that would dissuade me from trying it. I am currently trying styrofoam.

[BrooklynMatty]

Awesome dude, i stopped visiting the other forum recently due to too much drama.

Hopefully we get more traction here, for everyone's sake. Your in the heart of rice country, you should find it easy.

the main distributor for nurseries is http://www.riceland.com/pages/contact/ and its in Arkansas. Thats the product i found online, PBH.

[Kelby]

A nursery I buy from for work sells most of their plant material with an inch or so of rice hulls on top of the potting mix. Makes a mess!

[BrooklynMatty]

I bet its a pain in the ass, especially if its at the top. But it makes it look pretty right

Next time sweep up all the rice hulls and bring it home

[don_sanders]

Not much rice growing around here or hulls available that I know of. Lots of corn though. Crushed corn cob bedding could make an interesting potting mix additive if it isn't to small.

[Bluemalibu]

The only cautionary note that I've seen about cob substitution for Perlite, is in reference to its N tie-up. It decomposes much faster than rice hulls, so, with adequate nitrogen supplementation, it would be a cheap alternative for you.

Rice being a water plant, decomposes at a glacier pace. They flood the stubble fields here, and have to dump manure from the dairy farms into the standing water to help promote some brake down. Another whitepaper presented a two-month study of the rice hulls as growing medium, which showed no measurable decomposition.

[don_sanders]

Interesting. That kind of surprises me about the cobs. I threw some in my compost pile and that was the only thing distinguishable when the pile was done. Their still sitting on top of my flower bed because I never picked them out. They were whole though. Maybe a good experiment one day.

[Charlie]

Rice hulls are also good for growing mushrooms,meaning fungi will readily colonize it. Not necessarily a bad thing if the right fungi.

[BrooklynMatty]

Fungi is great stuff. When shrooms grow from my soil that means it's thriving.

[AscPete]

I haven't tried Rice Hulls but have already eliminated Perlite in my potting mixes. For trees older than 1 year in 5 gallon containers my preferred mix is now 2-4-1 (sifted PBF - Peat Moss - Calcined Clay), the PBF is sifted through 1/2 and 1/4 hardware cloth, the smaller fines (up to 1 part) smaller than 1/4" is added to the Peat portion of the mix.

The PBF (Pine Bark Fines) and Calcined Clay (Tractor supply Oil absorbent) have provided sufficient "large" particles for long term aeration of the potting mixes. As a note Turface which was the original Calcine Clay product used in Al Tapla's 5-1-1 and Gritty mixes is rated for 20 years with only a 4% reduction in size!

http://www.turface.com/sites/default/files/_media/resource/turface_mvp_sheet_6-12-13_0.pdf

[AscPete]

@ross
Have no idea about compost since they are all made with different ingredients but,

http://hortsci.ashspublications.org/content/25/10/1228.full.pdf

lists nutrients in Pine Bark and Peat...

[Rewton]

Pete, do I understand correctly that you discard any pine bark that does not go through the 1/2 inch mesh and you then take the the material that goes through 1/2 inch mesh and re-sift through 1/4 mesh, keeping what doesn't go through for the PBF fraction, and what goes through as contributing to the peat fraction? (Sorry for the run on sentence!)

[AscPete]

@Rewton
Yes, The chunks larger than 1/2 inch are "grated" through the 1/2 inch hardware cloth. The particles smaller than 1/4" are added to the "Peat Portion" to help create the "fines" in the 2-4-1 mix which is actually 3 parts Coarse (PB and CC) to 4 part fines (Peat Moss and PBF)...

[ThaiFigs]

I use rice husk as perlite too expensive here and rice husk dirt cheap. Mine isn't even parboiled but it doesnt create a huge weed problem. In fact its a great mulch since it dries out so quick that weed seeds usually cant germinate.

But be careful it can bring in pesticide residues.

[BrooklynMatty]

Dieter - Where you live i know perlite isn't as common and rice husks are, so that makes sense.

PBH(riceland) - is OMRI listed and wont have pesticide residues (most likely during parboiling process), so as long as you use that you're fine. You're getting the stuff locally I'm assuming where there aren't as strict limitations on what is done. Dirt cheap is great

Can you share some pics of your mix or as its used for top dressing?

[ThaiFigs]

[BrooklynMatty]

Nice! That pot aint moving

[ThaiFigs]

You'd be surprised. It has no bottom. So the tree roots will eventually expand out from under the "pot" in all directions and anchor it in place. But right now I can still move it by myself. Barely.

[CoolClimateFigger]

I've seen the rice hulls in the hydro shops here, but nowhere near $8.

[BrooklynMatty]

Yea - they get it in bulk for dirt cheap and can upcharge ALOT for this "Organic" product. I now see how these hydro shops can upcharge so much, been on mainly distributor sites recently. Certain items are SOOOO cheap.

[BrooklynMatty]

Update guys:

My really bad week has just turned up and wound up getting 2 bales of the rice hulls for $16 shipped, i think because they did a poor job packing my pots last time and i have spent so much in past year they gave me benefit of the doubt. I will be posting updates throughout the year on results, but away goes perlite in my grow medium (minus the remaining fafard mix i have left) $16 is probably $100+ worth of perlite without the dangers and issues with sizes.

Per Pete's comments, i will probably do adjustments to my ratio as i thought i would. But it will be Pine Bark Mulch/Peat/Rice Hulls. Most likely 5/2/1 or maybe 4/2/1. Not 100% yet

[BrooklynMatty]

Blue - Happy Endings are great

Tony - i just ordered it, hasnt come. But there should minimal dust (no where NEAR perlite) and its not dangerous at all. Its OMRI listed and i cant find an SDS on it, so i dont think there is a safer product.

[Fygmalion]

Matt... Low to no dust would be a great ending for sure... perlite is a good product but the dust dangers have really been concerning me... Thanks...

[BrooklynMatty]

Tony - one of the main reasons i dont want to deal with it. Especially since i have a 2 year old who runs around alot when im doing my gardening, i dont want her exposed to that danger.

[ThaiFigs]

Fresh rice hulls have practically no dust. Cocopeat is dustier.

[Fygmalion]

Good to hear...Thanks!

[Harborseal]

I've gone even simpler. I use 90+% pine bark. All I add is whatever's cheap for fertility (tomato tone, compost, worm castings, whatever) and mycorrhizae (Dr Earth, usually) and sometimes some pro-mix HP bio-myco for the pathogen eating bacteria and a little extra Glomus intraradicies. Pine bark holds water pretty well so I don't think the calcined clay is all that necessary plus it adds weight that I don't need. I add some Osmocote plus or Dyna Grow Grow for trace elements as needed.

[Charlie]

Been considering that myself. Pine sawmill in town has piles of it. Have you tried it for starting cuttings?

[BrooklynMatty]

Pine bark near me is the most expensive part of my formula; I wish I could get in bulk.

Charlie - I used the 5-1-1 formula for all my newly rooted cuttings. So once they had a little bit of roots from coir bin,bag or cloner. They went right in my 5-1-1 and they loved the pine bark. All the air pockets let them grow like crazy and they could never be over watered. I would not change a thing, it sucks watering them daily though.

[Harborseal]

Good point. I do get mine in bulk and I go through 4 Cu yrds/year or more. It's still $2/cu'. Luckily for me they deliver it free to my driveway.

[BrooklynMatty]

Delivery time!!!!

UPS dropped off my two first bags of Rice Hulls today, can't beat this deal= $16 shipped. The quality is great and i'm glad it only came with one small hole in the bag (its double bagged). After checking out the raw material, there is almost no dust from pulling a handful of this stuff out and the size is smaller than what i expected, but i think once hydrated it will get larger.

Will probably use this if i ever get around to rooting cuttings this season as a top dress for gnats, then will start making large batches of medium for up potting in march.

[AscPete]

Thanks for the update....

Now is probably a good time to mix up and water a few test batches and see how well the Rice Hulls "age" in the mix.

[lilfiggy]

ok no rice hulls to be found yet but in reading up about them I discovered that they are also used in beer brewing and for liter in horse stalls and poultry coops Will keep investigating for a source here in Florida

[BrooklynMatty]

keep looking around, it is hard to find. amleo.com is only place i found it online. As far other locations, try greenhouse supply shops that order in bulk, near me thats Griffins.

[lilfiggy]

Alert: All Fig Friends I found them at a local beer and wine home brew store they sell them bulk for 1.25 a pound I can buy as much or as little as I want and best of all no shipping will be picking some up today. Best of all I passed by the store all the time and never knew it was there. Hope this helps everyone

[BrooklynMatty]

Most brew shops are 1-2 dollars a pound, which is not a real bargain. Be very careful, as most places are 7-15 bucks for 50# bags.Perlite is cheaper at that point.

[don_sanders]

I decided to pick up a couple of these bags of rice husks to give them a try. What ratios are you using in your mixes? What do you guys think of a 1:1:1 of compost : peat : rice husks? I currently use 2:2:1 compost : peat : perlite mix which is about $61/yd while the rice husk mix would be about $42/yd. Most of the savings would actually from using less peat moss which is a majority of my cost. I was thinking about using about 33% rice husks because I think I recall reading somewhere that it works best at around 30% of a mix.

How long have the rice hulls been lasting for those that use them?

Would you use rice hulls in a 30 sip that you wouldn't up pot for 3 years?

Any other tips?

Thanks!

[Fygmalion]

A question came to me and I apologize if it was already asked and answered but... do the rice hulls attract vermin? Do mice, chipmunks and other pests eat rice hulls? I know they don't touch Perlite since it is a non salt based mineral which might otherwise attract salt loving creatures but what about the rice hulls.... Aren't rice paddies havens for rats, mice and other vermin that feed on the rice and thus consume the hulls and well as the germ?

Thanks...

[Bluemalibu]

The hulls have been a rodent magnet here, Tony. They chewed into the double-layered thick plastic bags and I found an 8" high sea of hulls, over 2 yards wide, in the potting barn, as they dug through them looking for the rice that they had once held. Likewise, about three dozen rooting cuttings were dug into, and the cuttings chewed... that has never happened before.

[don_sanders]

I read that they will attract birds if used on top of pots as well.

[Fygmalion]

Thank you for the feedback Doug and Don! I will have to keep an eye on it once I mix up a test batch or three and see what the collateral implications resolve to be.... last year I had a terrible problem with chipmunks digging into my potted plants on a daily basis and I ended up cutting 1/4" chicken wire screening to lay on top of each pot to deter them. That worked very well .... This year may end up being a repeat in those cases where a large SIP isn't being deployed which has the soil top covered with 3 mil plastic. I am really hoping that vermin prove to be disinterested in the rice hulls since as Matt suggested, they shouldn't incentivize vermine with actual rice germ to consume; I would rather not use Perlite due to inhalation concerns on the one hand but I don't want to introduce a different problem altogether considering my property is completely surrounded by watershed lands and reservoirs with what I imagine to be an endless supply of vermin if they should think the rice hulls to be attractive... Time will tell the tale....

[lilfiggy]

no on my end. Only see lizzards on the screened pool area , no mice or rodents. I like the lizzards as they hang around potted figs and do bug patrol yorkie does lizzard patrol and keeps them alert. No lazing about. Of course occasionally they will lose a tail as they are flung to the winds.

[BrooklynMatty]

I decided to pick up a couple of these bags of rice husks to give them a try. What ratios are you using in your mixes? What do you guys think of a 1:1:1 of compost : peat : rice husks? I currently use 2:2:1 compost : peat : perlite mix which is about $61/yd while the rice husk mix would be about $42/yd. Most of the savings would actually from using less peat moss which is a majority of my cost. I was thinking about using about 33% rice husks because I think I recall reading somewhere that it works best at around 30% of a mix.

How long have the rice hulls been lasting for those that use them?

Would you use rice hulls in a 30 sip that you wouldn't up pot for 3 years?

Any other tips?

Thanks!

Don - I have decided that i am going to be doing a 2-1-1 (bark/peat/rice hull) ratio which is close to the 30% optimal percentage that was done in some previous research mentioned. I did this to keep costs down and have some water retention from the peat and bark.

The people who have used it mentioned it lasts about 2-3 years before it really breaks down and composts back into soil, which breaks down into silica (good stuff). I think using this in a sip would be fine for 2-3 years as iit should break down and you would up-pot. But most of the people trying it like myself are starting this year, dont think many people have been using that long to get into details. I will be reporting this years analysis and into next year as well.


Just whipped up 60 gallons yesterday, I am finishing an old bag of fafard mix with perliite, once im done with it tomorrow - no more PERLITE!~


Fygmalion I dont think you should have worries as there should be almost no rice itself in the riceland stuff for vermin to want. If you got the stuff Blue got, then theres an issue - since he got it straight from the source and iit still had some rice left in the mix.

[Fygmalion]

Thank you, Matt...

[AscPete]

BrooklynMatty ,

Any updates on the rice hulls potting mix?
Curious if you've observed any differences.
Thanks.

[BrooklynMatty]

BrooklynMatty ,

Any updates on the rice hulls potting mix?
Curious if you've observed any differences.
Thanks.

Pete - so far i have mixed up 200+ gallons of medium with rice hulls and i like it. It doesn't settle to the top like perlite does, i think it helps with drainage just as much as perlite. I have changed my ratios up so i don't have a 1:1 comparison. Since like you, i changed to a more retentive mix than the initial 5-1-1 or 5-1-1. I am now doing 2-1-1 approximately.

I also top dressed most of my plants with espoma products, so i cant tell until i start watering more frequently. since the espoma cakes on top till i mix it in and water alot.

But for the price and health benefits, i highly recommend it so far. Time will tell throughout the season on growth habits. Will keep everyone posted.

[Fygmalion]

I purchase the hulls but haven't mixed any with the Pro-mix HP yet... Next week likely will do so... You think 2-1-1 is the way to go then?

[BrooklynMatty]

Tony - last year i had 80+ plants in 5-1-1 and 5-1-1-1 mix and they grew like monsters, but boy did they dry out really quick. I went to excel and figured out ratios to best accommodate the 20-30% ratio of rice hulls that studies proved best. And with the rice hulls being 25% of my mixture, it helps costs since the pine bark is my most expensive part. I think this ratio should retain more water while still being aerated enough, i dont believe in compost mixtures as those need more attention and are not suited for younger plants, this mixture can be used from cuttings to 4 year old plants of mine.

I will see if it makes a difference this year

[AscPete]

Matt,
Thanks for the reply...
Good luck with the mix, looking forward to future updates.

I also top dress during the season, and find that premixing the Espoma-tone with a cup or two of wet "fresh mix" or Peat Moss keeps it from "caking" on top.

[BrooklynMatty]

Thanks Pete. I will keep people apprised.

Yea, i think moving forward i'm going to mix it in better, this was all in haste and i knew it would happen. Did it last year with rabbit manure and it became a shell on my 1 gallons.