re-amending "used" soil

Discussion in 'Growing Organic Marijuana' started by Smokey B McBongwater, Aug 20, 2019.

  1. Back in the fall I mixed up about 80 gals of soil. so far each grow every plant has gotten new soil. my current grow I finished up the last of the 80gal of original soil. After harvest of each plant I've either dumped the used soil into a storage tote or left it in the grow bag and just placed it in the attic storage room to sit. Will have a few plants of the current grow harvested in the next 10 days giving me about 60 gal of used soil I want to amend for the next grows. each batch of soil only got one grow of an auto so really shouldn't have too much taken away from the original amendments but just wanted to play it safe and make sure the soil has everything it needs for the plant, perhaps i'm wrong?
    The only notable item i think was missing from the original mix was alfalfa meal because I thought I was going to need it almost immediately and didn't think i'd have enough time for the alfalfa to cook enough avoid being too hot for new plants. Based on that I was going to go heavier on the alfalfa meal because I'm making up for not having it originally.

    I was think of putting in PER CF of soil:
    1/4 cup neem meal
    1 cup alfalfa meal (none in the original mix)
    1/4 cup kelp meal
    1/4 cup crustacean meal (split 50/50 crab meal / shrimp meal)
    1 cup azomite (went light on rock dust/minerals originally so adding would be good???)
    1/2 cup Gypsum
    3 cups EWC
    3 cups perlite to offset EWC's and meals

    I also have MBP but only used it for topdressing and teas. should I add in as an amendment?

    half the soil is in 2x 15-gal smart pots. they still have the timothy hay mulch sitting on top. Do I remove the mulch and compost it or leave it and mix it in with the soil for aeration and to breakdown? I wan't planning on leaving the soil in the 15-gal pots, idea was to mix in the amendments in a big bin and let it sit a few weeks until I need it than re-pot in new 10-gal pots.
    hmmm, my typing this now brought up an other question in my mind... if the above mentioned timothy hay is best to retain and mix into the soil, could that count as part of my needed additional aeration to offset the density of the EWC's and meals? that would be a nice double usage bonus.

    Since this organic soil growing is still pretty new to me I welcome any and all advice. Don''t want my soil lacking but don't want to overdue things just because I think it may need something but maybe it doesn't....

    thanks guys
    sorry to sound like a real newbie on this but when it comes to organic soil... well, i am! :)
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  2. You've got the right idea...If you wanted to,though, You could just leave the soil in 15 gal fabric pots after each grow, leave the old 'stump' in there,remove the mulch temporarily, scratch -in a cup or two of mixed amendments in the top of the soil, add the new plant in there, and replace the mulch lastly...and go for another round...over and over...
    That's how I've been doing my 'mini no - til ' beds, for several grows now...and let some worms live in it all the time...
    That keeps the soil web going strong.

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  3. thanks, but for my set-up the 15-gal pots are just too bag, take up too much space regardless how much i like the larger size. that's a main reason it'a getting changed out to 10-gal pots and not staying in the 15-gal pots. Otherwise I'd just amend in the pots, water it in and let it sit and cook until i was ready for it.
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  4. #4 Possuum, Aug 20, 2019
    Last edited: Aug 20, 2019
    smokey you've asked the million dollar question for what might be the millionth time by ALL organic grow-bros. iow, it's a guess and without proper soil testing it's anyone's guess. as i've made clear publicly in the past i am not a real huge fan of using recycled soil because of this very reason of not knowing how much of what to amend with. that said, i do use recycled soil and I've got ~4cf in use right now but it is certainly not my personal preference. here are my thoughts and my practice. does it work well? proof is in the pictures i think. in my current situation, "yes" it appears to work fine.

    plants use minerals in the ppm range - parts per million - and that's fairly miniscule in the overall scope of measurements. we know that plants use the macronutrients in amounts greater than micronutrients and of the macronutrients NPK specifically is used in greater amounts than Ca and Mg. all of these minerals/elements macronutrients are cations (+ charge). so we have to keep that in mind because if the "+'s" are not in balance with the "-'s" we're going to have ph issues. too many +'s will result in acidity and too many -'s will result in alkalinity. and yes, the way to 'not worry about ph' in organics is to ensure we have copious amounts of soil organic matter (SOM) due to the primarily negative charge of SOM attracting and holding on to the +'s. that's how it works. ok, so what?

    depending on how much "stuff" existed in the first round of soil use amending 1cf of soil with whatever you choose to amend with should be measured in tbsps or tsps and not in cups. the NPK amendments should be limited to 2-4 tbsp per cf. the minor macros should be in the range of 1-2 tbsp per cf, and the micronutrients should be in the range of 1-2 tsp per cf. four tbsp equals 1/4 cup and 3 tsp equals 1 tbsp.

    i think you are way too heavy on neem and ewc specifically. i wouldn't add more than one cup of ewc per cf for a reamend and i'd use no more than 2 tbsp of neem. as for the alfalfa one cup is good if you didnt have it before but be advised you will need to allow 7-10 days to let that cycle when it's mixed up because it will indeed get "cooking".

    dont forget opportunities to top dress and foliar throughout the grow so one can always add more of something but short of leaching the soil there's no easy way to get rid of excess of any one thing so go easy on reamend. make your list of the 16 essential elements keeping in mind how much (ppm's) a healthy growing plant actually needs.

    as for the timothy hay, the easily useable parts of the original mulch layer is gone. the straw you're left looking at is very tough to decompose. i dont want to get too far off into the weeds talking about decomposition but i will say this, the straw is tough and during its breakdown alcohols are created as a a byproduct of the decomposing lignin and you gotta know that alcohol in any form is deadly to a plant. try to remove as much of the straw that you can ime. one of the reasons we test our compost with veggie seeds is to ensure the compost is "finished". iow, it's all been broken down and processed and toxins of any kind that are harmful to a plant have been properly dispatched.

    That's all the so-called "help" i can offer. think ppm's, think 16 essential elements for healthy plant growth, and think in terms of tbsps and tsps when reamending. "less is best" my friend.


    edit: i dont see you using a dry, complete, fertilzer such as espoma or dte. i would 1-3 tbsps of a good 'bloom' or 'palm' blend of dry fert. look for one that carries secondary nacronutrients and/or micronutrients. i use espoma flower-tone fwiw. they're all about the same.
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  5. awesome, thank you.
    in many ways I agree with you on reusing old soil for the exact reason(s). When you first mix it you know what you put in, but re-amending you are guessing unless as you mention you get a soil test done. I'm not doing that. on the other hand I hate to throw out soil that is basically barely used. I'm most likely NOT doing another outdoor garden next year based on this years results so no avenue to re-use it outside. use seems wasteful. and last, being currently unemployed, until I find a new job I'd rather re-use what I have than spend money on new if i can make this work
    so hence the reasons for re-amending :)

    good info on the hay. I'm surprised, honestly figured I'd hear it was great to leave in and I should keep it but no problem, I'll pull it all out and throw it into the compost pile.

    I can reduce the 1/2 cup measurements down to 1/8 cup if that's better. that's only 2 tbsp per cf rather than 4. Actually surprised to hear you recommend reducing the EWC's, I kinda figured if anything that might have been the most overall beneficial add-in of any of the list. I can go down to 1 or 1.5 cups per cf if that is better.

    I keep hearing about chicken manure pellets. if it's worthwhile I could pick up a small bag and add some in. I had both cow and chicken manure compost in the original mix, but not the pellets.
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  6. Jeez, I just mixed my old soil half and half with compost from the store, threw garden leaves in and it is working fine. However, I am not an organic grower and use chemical nutriates, and am only on my second grow ever

    Sent from my ANE-LX2 using Grasscity Forum mobile app
  7. thanks but i use zero bottled nutrients so depend on my soil to provide my plants everything they need. if you are bottle feeding and your soil is lacking anything it doesn't matter because the plants are getting everything from the bottled nutrients.
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  8. @Possuum

    EDIT: just saw YOUR edit. In the original mix there was Espoma starter mix, and the pots were also top dressed once with some Dr. Earth tomato, veggie, and herb dry ferts. I still have some of both left if it would be good to add some. sounds like it would be good to add another 1/8 tbsp the Dr. Earth at least.
    Opinions on 1-2 tbsp of epsom salt for "p" later on for flowering time??
  9. #9 Possuum, Aug 21, 2019
    Last edited: Aug 21, 2019

    actually i suggest you add 1-2 tbsp of espoma and cut in half or one quarter whatever is recommended for epsom salts for Mg. you know how i feel about foliar feeding and epsom salts is an excellent choice for foliar feeding if supplemental Mg is required. excess Mg is not something you want in your soil. it will cause problems with Ca absorption with the root system. so if you add the granular version personally i would use 1/2-1/4 of whatever is recommended. there's probably trace Mg in your dry complete fertilizer and definitely trace amounts of Mg in kelp. adding 1-2 tbsp of espoma per cf for an amend or top dress is acceptable in the world i operate in. if it comes to the point you need extra Mg apply it foliar style or use kelp.

    re the ewc, the reason i suggest only one cup is because you should have the same amount of ewc in your used soil you started with minus any decomposition or leaching. plants dont eat dirt or soil organic matter, they "eat" (absorb) ions. the concern is making your soil too heavy and lacking good drainage, and poor porosity if the texture gets too dense. my think on my recent reamended soil was to add 3-4 tbsp in the bottom of the new planting hole, set the plant and use a mixture of old soil and fresh ewc to fill it directly around the new root system. i also emptied each container completely, left the majority of root system in the mix, added my reamend, mixed well and started all over again. no no-till for me in the 7.5-10 gal size. dump it, clean it, chop it up, ready to add to and replant. i also use composted pine bark in my mix and reamend. ~4 cups on a fresh mix and ~1.5-2 cups on the reamend. i love composted pine bark as much as ewc albeit for different reasons. it's not a "must have" but it sure does work great.

    just curious how you went from 80gal to 60gal of old soil? did you repurpose 20gal for another use? perhaps you're just not going to use it. that just seems like a lot of 'missing' material.

    listen, i'm constantly experimenting on the processes that i use that meets my needs, budget, and output. for me i've got it dialed in very good for all those parameters. i've got plenty of pictures to back up my final work so the things i talk about i actually do BUT what i do may not meet the needs, budget, or output of someone else's project. that said, ive put a lot of work into thinking about and employing these processes and they darn sure work pretty well for me. i take absolutely nothing away from all of the tried and true recommendations herein the O section or popular printed material that lay the baseline for media mixes, but what i seemingly have accomplished is finding the right amounts of 1/2 cups, tbsps, and tsps of ingredients to hit that perfect mix of elements with good balance of ph that lasts throughou a 4-5 month grow. i top dress at 30 day intervals with what might amount to 1/2-3/4 cup total of my amendment mix and the rest of the time the media gets tap water, and any bumps of 'special needs' i will address with a foliar spray program. all this has been working out pretty good for me for quite awhile now.

    so, for reamending used soil i am guessing just like everybody. the reamended soil i'm currently using based on the above standard seems to be working fab at my current 30d mark for these autos. i'm confident i'll make it another ~40d using what i started with, a minimalized reamend, and just just sticking to my top dress and foliar routine. i know for me personally comparing what i used to do with adding quantities of amendments to start out, like seemingly everyone else was doing, to what i do now for my media mix is seemingly now the antithesis of what everyone else is doing! i mean man. ive taken what i perceive to be required amounts of nutrients successfully down to the 3-4 tbsp or less of each per cf level. the reamend was in the 1-2 tbsp or less of each.

    i really hope this helps you and others and gets you to thinking about what is really required to grow a plant effortlessly and successfully - it really is minimal. try to get you thinking small, a ppm type view at the ionic level for organic growing, and to give consideration to how much is really enough - the balanced amounts - such that resources are not wasted and perhaps most importantly that excess materials dont cause real problems based on the actions of cations and anions which is always in constant motion.

    cheers. happy to offer my thoughts. they either stick or not. cheers! :smoke:
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  10. so, my take-away from this is that you recommend something like 3-4 cups, whatever, of everything I have on hand just to make sure i have all the basics covered. no worries about overdoing thing - just dump a LOT of everything in the soil... LOL LOL LOL :) :)

    I'm seeing a common theme here from ya... small!! :) can deal with small amounts! that just means less of it therefore less expense. I'm all on board with that. :)

    i'm like you on the no-till currently. I'm not doing a proper no-till growing. and the idea was to dump the soil out of the bags, remix, than rebag in the new 10-gal bags. only doing that because I can fit 3x 10-gal in my tent but only 2x 15-gal. Otherwise for now I'd leave the soil in the 15gal bags and just topdress some alfalfa, kelp, etc, water it in and let it sit for a few weeks and re-use it. simple. hmmm, too simple... is sounding tempting. make life a lot easier and less work at the moment. one less plant in the tent with the larger bags but I'm planning on moving tent operations to the basement in a few months so maybe a smaller grow at the moment would be better.... hmm. going to re-think this. may change directions on this now that I'm thinking about it more.

    Oh re: the 80gal to 60gal. The "missing" 20 gals aren't missing, lol I was calculating the 42 gallons I have currently sitting plus the anticipated the soil from the plants I'm going to be harvesting within the next week or two. that's the 60 gal. the other 20 gals of soil is in pots of plants still growing and won't get harvested for another month or so. figure I'd re-amend THAT soil during the NEXT re-amendment process :)
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  11. @Possuum
    now you got my brain going nuts thinking of the best way of dealing with this, without going overboard, without getting overly complicated (which tends to be my specialty...). Think I'm going to go with plan B which you got my brain started thinking on earlier.

    I really want to move my med and veggie tent grows down to the basement and planning to expand the veggie tent HUGELY - like a 10x10 size or so, and increase the med tent to maybe a 4x8.
    can't do it for a few months at least for a few different reasons but point being I have ion my mind already that my current grow op is now going to be phasing out hopefully after the next grow so instead of the planned 4 plants I'm thinking I'll go back to what I did LAST grow. The 2x 15-gal bags I already have, and I can squeeze in a single 5-gal between them as i did. I'll do a fast finishing strain in the front center 5-gal bag and it will finish up just as the 2 larger plants are just bulking up and need the extra room.
    once those two finish hopefully I'll be ready to move into the basement.
    with that plan I'll leave the 2x 15-gal pots I was going to dump and remix and repot, but I'll leave them as is, topdressing a small -re-amendment mix (mostly the original missing alfalfa, some kelp, a little fresh ewc), water it in, let it cook a few weeks and use use as is and i bet it will be just fine, after all, how much nutrients could a single 3 month auto take out of 15-gal of decent soil as you make the point of :)
    same as ai did here
    (btw, that's a blue dream auto on the left, Dark Devil auto in the middle 5-gal, and LSD25 auto on the right) That LSD25 in particular is NICE. very potent! :)

    the larger 15-gal bags give a lot of room for LST also which is another benefit :)

    yeah, this is sounding like a simpler plan, easier, and probably better overall anyway rather than trying to squeeze in that extra 4th plant. with the larger sized bags i can try a few seeds i have that I hesitated on before because of the advertised size of the plants but now I'd have more room to train and LST them under control.
    yep, this is sounding like the better plan. :)

    thanks dude, I realize this change of plans wasn't your intention per se but your post/thoughts got me thinking more and overall I feel this will work better for the moment. and again, EASIER which I like!!! :) :)
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  12. For smaller pots and smaller amounts of soil I think re-amending and mixing it is the way to go. @Possuum is spot on when he says you asked the million dollar question.

    At the height of my soil mixing career, I had enough soil for 3 runs around all the time. One batch was for plants currently flowering, another batch was amended and mixed after the previous run (a plant or two is tested in this soil w the plants now in flower) and finally a third batch that has been amended and is cooking, just waiting for it's turn to be tested on a plant or two.

    The tester plants are observed carefully. If they fade fast I know I can topdress (or even mix in) more amendments. If they are dark green and clawing, I know I can "cut" the mix with peat, aeration and lime.

    It was a lot of work but I was doing this with around 1,000g of soil. It does take some of the guesswork out of the game. It greatly reduces the chance of total crop failure.

    Long story short, do a bioassay on any soil you 'recycle'. Those faster flowering autos would be a good candidate for this sort of thing. As the soil goes through a few cycles the less it should need each time you amend/mix it.
    Edit: Saw the part about the veggie tent. A tomato plant would also be a great candidate for a bioassay.
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  13. LOL a tomato plant cutting was the "test" plant for my current soil, the 80gal batch.
    first version was actually only 50 gal but i messed it up and the first tomato cutting died in the first 24 hours. poor thing had a horrible death... suffered badly, the poor girl LOL
    i remixed and fixed the problem in found in my recipe (well, others on here found it lol) and i diluted and remixed to come up with my 80gal batch./ than another tomato cutting as a test and that plant not only loved it but became a hugely productive cheery tomato plant that also mothered a bunch of cuttings for about another 1/2 dozen tomato plants so far. based one the tomato plant results I used the soil and my med plants have been liking it so far. :)
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  14. As far as amounts go I'm no help, it's been too long for me. I would be very careful about adding liming agents - crab shell and oyster shell. Too much of these can get you in trouble quickly especially if you're using alkaline/hardwater already. This shouldn't be confused with water that simply has a high pH.
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  15. Sounds like you already have a good system in place. Simple but smart. Avoids throwing all the eggs in one basket.
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  16. I like simple. simple is easy. i like easy because i'm basically lazy and the older i get the lazier i get. the less work i have to do the better. :)
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  17. #17 Smokey B McBongwater, Aug 21, 2019
    Last edited: Aug 21, 2019
    I was figuring on the crustacean originally thinking about the advantages of the chitinese ??? sorry, don't know correct spelling. isn't that suppose to help make the nutrients more available to the plant? that is what I was basing it on. I'm probably wrong which is why i list the item i was thinking g of using so I would get feeback on them.

    I really have no idea of the breakdown of my water, never had a test done. all i know is from my hydro days my ph and ppm pens told me my ppm was 400 out of the tap and ph 8.2. not exactly great water but so far I'm not seeing any issues, but i've also only run soil through single grows of autos so not a lot of time to have the tap water really mess up the soil, IF it's going to. I also put a lot of various types of compost in the original mix so i had a big "buffer".
  18. I will throw in my $.02. I am just getting ready to make up pots for my winter grow, which will 10 gals, that I expect to get 3 crops of autos from.
    About 18 months ago, I finished a grow, and re-amended 40 or so gallons of soil at about 1/4 rate in the notill recipe. I only added crab, kelp, and neem. This was put in a tote and was crawling with worms at the time. I use this stash as part of all of my mixes. I strategy is that this portion of soil has amendments completely broken down, and nutrients are available immediately if needed.
    I kind of break things down into a couple steps, but I normally make everything in small 8-10 gallon batches to assure the best consistency.

    I use
    2 gal leaf mold, homemade
    2 gal compost, homemade
    2 gal perlite
    I add 1/2 cup each neem, kelp, and crab
    1/4 cup lime
    2 TBS gypsum.
    (rockdust and biochar are in the compost and leaf mold already)
    The above is well mixed.

    I then add 2 gallons of Sinse's mix vmc (with amendments and rice hulls and bark used in its creation)
    I then mix well.

    I then add 2 gallons of the recycled soil mentioned at the beginning of this post.

    IMO the fresh compost and leaf mold is what makes a difference.

    I do end up with lots of extra soil over time, but I use it in beds outdoors and for veggies etc. BTW it works kick ass! I grow some kick ass flowers and veggies.

    Part of the reason I do this method, is because I am convinced that every batch of compost and leaf mold, is the best I have ever made.
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  19. If you're on city tapwater you can probably Google search a water report or call your local water department. It's already a suspect w the info you've given. You may even find that it's not suitable for long term use. Perhaps it's on the upper limits on Ca and Mg and adding more via liming agents may cause issues. Hard telling not knowing.
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  20. hopefully I'll have homemade compost by spring...... :) :) doesn't do me a lot of good now though.... lol

    sounds like my BEST method is just have you make me a few batches. do you deliver?? LOL

    btw, i was looking at the beginning of this thread the other week looking up something, i have a question, maybe I saw it wrong?
    on your pots, you use a 10-gal fabric bag, in a hard plastic pot, lave rocks on the bottom as a sip area for the bag to wick from, and wrap the top of the bag over the edges of the hard pot.
    did i see the size of the hard pot was only 7 gal? or did i misread something? and if only 7 gal pots, once to put some lava rocks on the bottom, you are ending up with approx what/ 6 gals or so of actual soil? or am i missing something.
    if the hard pots are also 10 gal it makes more sense....
    rockdust is something i definitely need more of. the only real minerals i had was azomite. can't seem to find anything else locally. maybe have to breakdown and order online but hate paying shipping charges for frickin' broken up rocks.

    i also see what i suspected and was afraid of from the beginning - there is no real answer to my foolish question. As mentioned, it's the "million dollar question". should have realized it before i posted.

    i'm just going to go with the overall general advice which seems to be SMALL amounts, mix up well, most likely less is best overall. I'll add a few items like alfalfa i know was missing and go very small on anything else.


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