is there a way to replenish / reuse old soil?

Discussion in 'Organics' started by nickbbad, Apr 25, 2009.


    nickbbad New Member

    So I have an indoor soil garden that I do and I am constantly tossing old soil and buying new soil... Is there a recipe to replenish old potting soil so I dont have to constantly be buying new soil all the time? I wouldnt mind so much but to get good soil I have to drive 1 1/2 hours each way and it ends up costing me over a 100$ just for soil. Any help would be great.
    arizona jim

    arizona jim Well-Known Member

    iv always heard NO on reusing soil.

    GoldenGanja13 Well-Known Member

    I had to help a guy tune up in his garden, it was dieing, so I watched what he was doing and one of many mistakes was he was reusing his soil. He thought becasue he flushed the soil with boiling water it was safe and good to use. The answer is no it is not good nor safe to reuse.
    If you have to make long trips, buy more soil and make less trips.

    Ohsogreen Well-Known Member

    I've been reusing some of the same soil I started with over 11 years ago. The people who push the " Just Say No to Reusing Soil " are the guys wanting to sell you new soil every grow. IMO that's a complete waste of money.
    Let's be honest, do farmers or even home gardeners, avoid using the same soil to grow new crops, of course not.
    Take the soil from your finished grow and put it in a compost barrel, add browns & greens (leaves & grass clippings), left over kitchen waste (no dairy, meat or spicy foods), moisten & turn weekly. Throw in a cup of High Nitrogen Bat Guano or three cups of Rabbit Manure to keep the tribe of micro-beasties alive & kicking. With a source of N, they will reproduce & bio-convert all the insoluble NPK in the left over soil into soluble NPK, plus make the soil more friable.
    In 14 to 28 days, if turned weekly, you have a good base to mix your own soil for the next run. Use this compost as follows: New soil mix : 50 percent compost you just finished, 30 percent peat moss or well rinsed coco coir, 10 percent perlite, and 10 percent worm castings.
    This mix will be mellow enought to start seedlings in with no risk of burning.
    Then feed your plants later using wholesum organic fertilizer teas : Read - Making Tea is E-Z & cheap thread......
    There is not reason to ever scrap used soil, it can & should be recycled indefinately - just like in nature.
    Hope this helps....
    Keep it Real....Organic......

    RandomKindness Well-Known Member

    Here's a reprint of a serious classic. Thanks to 3 Little Birds, PassionForMaryJane of Planet Ganja, Dan Kay at IC Mag, and Mendel & The Flinstoners at TCC
    ************************************************** ************

    We are about to commit heresy and tell people that we ALWAYS re-use our soil. No soil has left the garden's of the three_little_birds since before the turn of the millennium!

    Some growers will tell folks to throw out their soil after every grow, and we've known plenty of commercial growers that happily do that to make sure they do not have pest or nutrient problems. Maybe that even is the best solution for your grow, we can't say for sure, as always your mileage may vary.

    We are poor simple medical users (and aging hippies, etc.), and spending something like $20 for a bag of FoxFarm soil rubbed us wrong! With our container system it might take 2 full bags of that soil for 3 plants!

    Now again . . . Someone who is involved in commercial (rather than personal medical) production might not be so inclined to bother with making sure their soils stay healthy and all the work we go through to ensure our soil's health, but for us it is a labor of love and we feel our results speak for themselves.

    Anyway, like we said, our soil never leaves our grow, it has all been recycled to the point that we could not even begin to tell you how many times it's been through our system!

    A good commercial potting mix has always been the base for our soil. We look for a product which is 100% organic, and recommend that you avoid ALL chemical salt ferts like the plague if you value your soil health. This especially includes timed-released chem ferts like osmocote!

    Depending on what we have found for soil, we go from there. Some cheap organic soil mixes contain little more than peat, pearlite, and dolomite lime. These absolutely need amending to start off. Some organic soil mixes are much more complete and need little or no amending for starters.

    Organic mushroom compost is certainly one of the hot soil mediums these days, and we've certainly had great success mixing it in with our soil remixes to add fresh organic matter. We can't however comment on it's longer terms effects in soil remixes. Since we found a cheap source of mushroom compost, we have also been top-dressing our plants with it almost exclusively, so we imagine that we will soon discover if remixing the ‘shroom compost will have any detrimental effects.

    Once through it's first grow (the plants fed 100% organic with earth juice, teas, fish ferts, and liquid kelp) our container of soil has it's root balls pulled and it is dumped into a very large rubbermaid container w/ a lid (50 gallon container) These container's are longer than our 2x3 growing containers, so with 2 people lifting and dumping, it's not too hard to keep this step neat. Each bin can actually hold more than the contents from a single grow-container (2 grow-containers of soil will actually fit, but this makes mixing in amendments very difficult and messy.)

    Now we proceed to give back to our soil mix what our plants have taken (and then some.) We get out our kelp meal, bone meal, blood meal, greensand, rock phosphate, diatomaceous earth, and dolomite lime and get mixing. Depending on the soil's condition this is also where we might add a little more perlite if soil compaction looks to be a potential problem.

    Folks are going to ask us how much of these different supplements we add, and the only honest answer we can give is - it depends! If the plants we'd raised previously in that particular container had shown any signs of being short on a major nutrient N–P-K - it's not too hard to throw in an extra cup or two of the appropriate organic supplement (Blood meal / Alfalfa meal for N - Bone meal / rock phosphate for P - kelp meal / greensand for K and other micro nutrients.)

    A nice full 16 oz plastic cup of each of the prior mentioned ingredients would be our baseline for supplementing this round of soil re-mix. We will generally double this amount if any nutrient shortage has shown. . .

    The greensand and rock phosphate are very slow to dissolve and be absorbed by plants, and are not normally used by many indoor container gardeners. Their slow release is what helps to make our system work! They will still be in our soil for the next couple of grows, doing their part for our soil health.

    This is the point where we would also add some of our own compost (assuming there is some finished and ready - if not some mushroom compost has proven to work.) Our compost is made from the usual standards, household veggie food scraps and such, with the addition of all our used grow scraps. Fan leaf, chopped stems, and the "leftover's" from processing by bubble bag or tumbling are all composted and returned to our soil.

    Now we will wet this whole mix down lightly and let it "cook" for a spell. We have three large bins like this for soil remixing and composting. Folks always want us to be specific on amounts and times, and we do a lot of this by feel, so when we say we let the soil cook for a "spell" - how long depends on feel and need!

    The minimum time our soil sits is two weeks, and it's sat waiting for use for a couple months like this during slower times in our grow. This time gives soil bacteria a chance to work and make the various organic amendments more quickly and easily available for our plants.

    We use this soil again for another grow, watering with our usual array of teas, Earth Juice, etc. If needed, containers are top-dressed with compost (our own or mushroom compost depending on availability) as any soil settling occurs.

    Upon yet another successful harvest, the soil is reconditioned again. Once we reached our third mix of soil, we cut back on the soil amendments. The greensand and rock phosphate are still working from the last re-mix so we don't need to add any more of them for sure. What remains in your soil at this point in terms of nitrogen and such may depend on your strain, some strains are much more greedy for some nutrients.

    So if our plants haven't shown any signs of yellowing as they mature, we figure there is nitrogen enough in the soil for the next round (at least to get started - we can add more N on the fly with fish ferts and teas if needed) and no blood meal is added. If yellowing has occurred then blood meal is added again.

    Kelp meal is usually added again since many of the major liquid organic ferts seem a little short on potassium, and also because we like the micro nutrients kelp meal provides to our plants.

    Dolomite lime will probably be necessary again too, and it's possible your soil will need even more this time than last. Any peat in the soil adds acidity as it decomposes, and the lime balances this as well as providing magnesium.

    After the standard 15 - 30 days of standing moistened waiting for use this soil is used still another time. Now our soil has grown 4 crops of herbs and is still going and growing strong. At this point, we have started plants in our soil remixes directly alongside plants in fresh potting soil, just to make sure our mix wasn't subtly stunting our plants.

    The plants grown in our 4th and 5th generation soil remix did far better than those directly alongside grown in fresh from the bag FoxFarm OceanForest potting soil!

    Because our garden is a continuous harvest setup, once we are to our 4th or 5th remix, it's starting to get hard to keep track of exactly what soil has been remixed where, since half used bins of remixes are often dumped together to make room for another round of used soil coming from the garden. So we simply continue adding amendments by feel as needed.

    This is how the three little birds use soil. We know we break the rule we have all been told to follow - to never reuse soil. Even those "radicals" we have seen reusing soil, have always described letting their soil go out to their veggie gardens or flower beds after 3 or 4 grows. We decided to push the envelope and see how far we could take it . . .

    We still haven't found a limit for the number of times we remix our soil, and our harvests and plant vigor keep improving.

    Oh, just to add another bit of heresy, you may have noticed our container grows suspended above the floor on wheeled furniture movers. It's a very convenient way to keep the plants in larger containers mobile. . . But you also must realize then (if you think about it) that out grow containers have NO drainage.

    Our soil mix, which is now has been remixed double digit times, has NEVER been flushed!

    We warned you all at the start of this post that some might consider it heresy . . . And we can’t even begin to tell you how we can break these rules and get better results than average - but it works for us and we wanted to let folks judge for themselves.
    one thing we might add - we certainly would not remix soil from any containers where we'd had a bug or disease problem - even getting bud mold would be enough for us to say - no thanks to a soil remix

    we were discussing this among "the birds" the other nite - and one line that a little bird said comes to mind . . .

    "Farmer's don't strip their topsoil after a harvest - or even a few - in fact their soil is their most precious commodity - why should it be different for indoor gardening as long as proper care is taken to build healthy soil?"
    Ohsogreen likes this.

    RandomKindness Well-Known Member

    3LB " old roots compost like anything else. And a few moving along with
    the soil have never caused any harm in our grow. The most important
    thing to remember is to keep your plants healthy and pest free from
    the beginning. If disease or pests strike your soil it will need to
    be discarded. Otherwise we're still reusing the same soils in 2004
    we used in 2003. And those were used in 2002 and 2001 and 2000 etc.
    our methods may not be for everyone. And we strongly encourage folk
    to use a keen eye to watch and "listen" closely to their plants.
    when we open a container of our remixed soil after it's
    "composted". It smells like fresh earth. And as long as that's the
    case we plan to keep using ours. We are proud to report that
    earthworms live in our soil re-mixes now. Not the big fat
    night crawlers that many folks associate with the word "worm". These
    are smaller red wigglers. Our container gardens aren't ideal habitat
    for worms. They are really too shallow. So in many ways we are
    amazed that worms manage to live in our indoor garden. And we use
    fish ferts and earth juice ferts in fairly high concentrations.
    again we are a little amazed that worms tolerate this. But we've
    had plenty of worms (red wigglers) showing up in containers that had
    been through their entire bloom cycle as they were being remixed for
    recycling. We figure that's a good sign that our indoor soil is
    healthy . .


    green sand is a slow release K supplement. Rock phosphate is a slow
    release K supplement. Both increase soil health and also contain a
    large number of micro nutrients - though not so commonly used by
    indoor gardeners, they are very common for soil building in outdoor
    gardens . . .


    since organic ferts are available more slowly than salt
    manufactured ferts. The "lead time" with composting your soil gives
    the beneficial bacteria time to start their work. This composting
    time also allows soil pH to normalize and nute levels to settle
    down/even out. We've done it ourselves when time and circumstance
    dictated. And the only thing we noticed different when using the
    soil immediately was that our plants seemed to suffer a little more
    transplant stress. This always disappears within a couple of days
    so is not a big concern. We'd guess that the "raw" nutes are a
    little harsher on the roots than they would be after composting a
    few weeks. As for ratios it's really something we rely on intuition
    and the eyeball for (ok there's a bit of science too - shhhhhhh).
    since we continue to feed with ferts throughout our grows. A good
    place to start would be at about 1/2 the rate of something like
    Vic's "super soil" for additional nutrients. That's a good
    "baseline" anyway. These days we're probably using something in the
    range of:

    6-8 cups alfalfa meal
    2-4 cups bone meal
    2-4 cups kelp meal
    4-8 cups dolomite lime

    those are the basic ingredients. Then we get into things like
    humates and green sand and rock phosphate that we don't add every
    time . . .


    dolomite lime should be available at Home Depot or Lowes kind of
    stores. Alfalfa meal can usually be found at feed stores. Even
    suburban areas have these near areas with stables. Just about
    anything can be found through but shipping
    costs can get prohibitive . . . Three_little_birds
    (3 birds are better than 1)"
    Sincerely420 likes this.

    GoldenGanja13 Well-Known Member

    Or just spend the $16.00 for a bag of fresh soil that has fresh and the proper amount of nutes in it. Go Out and Buy Some FOX FARM Ocean Forest Or Roots Organic. I have stock in both, but none in grass and kitchen waste.

    Ohsogreen Well-Known Member

    GoldenGanja13...... I've been growing since 78. I've done soil chem, hydro chem, variations of both, then switched over to True Living Organics about 11 years ago. The only ways to toxify soil to the point you mentioned, are over application of harsh chemical ferts or by mass overfeeding with organics.
    Soil should be recycled as a base. It's easily tuned back up, without the need for high dollar soil tests. It's simple, turn the old soil into compost, use the compost as a base and add to it over time in the form of fertilizer teas made from manures (rabbit manure, bat guanos...etc..) and let the micro-beasties (good bacteria & fungi) do for your soil, what they do to soil in nature. Improve & balance it, to a state that is most benefical for Mary.
    Reuse, Recycle, Reduce - all of those equal saving Money.......
    Keep it Real.....Organic.....

    nickbbad New Member

    :hug:thanks guys this will really help:hump: I will let you know how it goes... Thanks again

    GoldenGanja13 Well-Known Member

    You have been growing for some time my friend, Kudos. But we for the most part have no way/knowledge/time to reuse soil properly enough to even have half the benifits of new soil. Read some post and see how many people even wait for a plant to mature before inducing flower, or even how many people think that triming off healthy leaves is good. Most of these people are not hard core like yourself, they are new school and lack patience. What I try and teach them is 2 things, one is patience, two is, try and get everything to as close to optimal as possible. Reusing soil would not be optimal.
    ~ Namaste

    RandomKindness Well-Known Member

    yes it can be reused - if done right & organically
    South Texas

    South Texas Well-Known Member

    Very well done.


    nickbbad New Member

    Yeah I have used Ocean Forest for years and though Im not knocking it in the least I think replenishing my soil will get me more in tune with my plants needs and give me a better understanding organics in general... And I am in no way saying this is for everybody but I do have the time and patience to learn how to do it correctly.

    And South Texas I agree this should be a sticky or at least something similar so people know its an option.

    Again thanks for the help people!
    Let your life keep growing :leaf:

    GoldenGanja13 Well-Known Member

    Sounds like you will be one of the few that actually do it right and mix a good medium. High Times 2 months ago had a really good article on mixing your own. Look it up online and maybe get the back issue.:joint:

    MrBaker Well-Known Member

    I was given 40 gallons of used promix. It was given a quick wash to get rid of any salts left behind from the previous chemical fert grow (ruh roh raggy). We'll see if the wash was enough, or if the salts can overpower the microherd.

    3 little birds said to add...
    4 cups dolomite
    4 cups bone meal
    4 cups blood meal
    4 cups greensand
    4 cups kelp meal
    4 cups rock phosphate (couldn't find a small bag, and it's slow acting so I cut it)
    4 cups diatomaceous earth (also cut, see below note)
    30 lbs worm castings
    perlite to taste

    Although diatom powder was on-hand, it holds a lot of water and the promix does a great job of that by itself. There is high quality dolomite that can be added to deal with chemical or additive issues.

    All of this is in a 45 gal. sterlite tub, in the middle of a 2 week cook with espoma bio-tone being added as often as possible without making soup in the tub.

    If everything goes right then this mix can be reused and just need refresh on the additives. I read a lot that says the peat will degrade and something else will have to be added and that tree fiber stuff like cocoa coir is the "bee's knees" if you want to resuse soil more than 2-3 times.

    roo Active Member

    Agree with what is being said about reuse. Anytime we can prevent waste and keep the same quality of grows we should all capitalize. I have one question. It seems that buying each product separately can be confusing. Would this product work. It is happy frog soil conditioner.
    Any thoughts would be appreciated.

    Ohsogreen Well-Known Member

    Roo.... In a word, " Yes ". That's good stuff. Add 50 percent compost, 40 percent of The Happy Frog Soil Conditioner & 10 percent perlite and you are there.....
    Nice Avatar by the way.... I keep hearing Run DMC in my head everytime I look at it........" Baby's got Back " :)
    Keep it Real......Organic....

    roo Active Member

    Thanks for the quick reply. I will take your advice, it will be easier for me to mix it like you suggested.

    If I want that booty I better start a commercial grow cause she looks expensive. LOL.

    GoonSquad420 Active Member

    Good thread. Ive always wondered if it was possible to re-use soil. Ill keep watching this thread for tips. I have a bunch of old soil that I used for a bunch of indoor stuff and I dont think I have any pests or my plant would be chewed all to hell and be unhealthy. But oh well Ill see what I can do.

    canefan Guest

    I have to agree with Ohso and the others, complete waste of money to start fresh all the time. I have used this current mix of soil or the remnants of it since 2006 grow. Always goes back into the new compost and mixed in. The plants are happy which is the most important part, basically zero cost and the worms love it. I always figured if your worms are happy and thriving then your soil is good for Mary. Patience and a little hard work for the girls is the key to success every year.

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