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How To Save Money By Reusing Old Soil

Reusing old soil can save you money and improve overall soil quality. Rehabilitating old soil for reuse when potting or potting-on can have a number of advantages. Learn more about them here.

Contents:

REUSING OLD SOIL TO GROW CANNABIS

Unless there has been a disease or invasion of some kind, there is no need to buy new soil every time you want to pot a cannabis plant or repot existing plants. Simply reuse the old stuff. Revitalising and reusing old soil is easy and a great money saver.

Marijuana is a notorious glutton for nutrients of all kinds; nitrogen-hungry during vegetation and calcium and magnesium-demanding during flowering, cannabis will always leave soil depleted. With that said, there are numerous benefits cannabis provides as well; the roots fluff out and the overall soil structure is improved upon. Such is one of the many upsides to growing cannabis.

ONE STEP AHEAD

By keeping soil healthy to begin with, you can prevent the need for its radical rehabilitation prior to reusing. Regular fertilising, composting, and mulching of potted plants with ensure healthy soil at every stage of its life. When well-cared-for soil maintains its health, friability, water penetration and retention, it needs little modification when reused.

Companion planting also helps keep soil healthy, vital, and disease-free. When doing this, however, it’s advisable to plant in a bigger pot than necessary to allow room for companion plants to grow. A simple alfalfa, clover, and marigold mix will provide manifold benefits to plant and soil health.

OLD SOIL CAN BE REUSED

Uncared for and stressed soils will require amending prior to reuse. The soil may become hydrophobic, completely exhausted of nutrients and minerals, or with a collapsed structure. Soil that has been left to bake in the sun will certainly be leached of nutrients and will need to be modified.

MAKE SURE TO BE CLEAN

If your soil was invaded by a pathogen or is quite unhealthy for whatever reason, the best thing to do is simply put the soil in a bag and discard. Mixing it into garden beds or working it into compost could spread the pathogen to your whole garden. Sometimes, diseases can linger in soil even after you think they’ve left. This is true for several species of mite, fungus, gnat, and rot. Reusing the soil will certainly infect the new occupant. Be sure to wash your hands before touching healthy soil and plants. Wash the pots as well in warm, soapy water to ensure the vector has been scrubbed away.

WEED NOT WEEDS

Pasteurising old soil is a way to get rid of a number of unfriendlies. Grass and weed seeds, insect eggs, and fungal spores can all be killed by putting the old soil in a black garbage bag, then leaving it to bake in the sun for an afternoon. The heat will pasteurise the soil to be ready for use. It will also kill most of the friendly biota, so you are committed to soil-amending once you decide to pasteurise. Bake in the sun before amending so you don’t kill all the friendlies you add.

REDUCE, RECYCLE, REHABILITATE

Before reusing soil, it must have its texture and fertility improved.

The quickest route to healthier soil is to add 50:50 new potting mix to the old soil. Commercial potting mixes have the disadvantage of drying out quickly and they tend to be compact and have poor structure. They can be expensive, especially if you have a few pots to fill. They do, however, have the advantage of being an instantaneous solve to poor-quality soil and take little effort.

Depending on your outlook towards organic soil structure, you might not like the idea of wetting agents and crystals, slow-release industrially-sourced fertilisers, or hormone enhancements. Perhaps a more hands-on approach to the mystic potion for bigger buds is what you prefer. These ingredient guidelines will ensure you make a rich and well-draining, life-enhancing soil.

Adding compost is the most natural solution to improving soil. A 30:70 mix of compost will provide much needed nutrients and structure to depleted soil. If you are not a composter, there are commercial composts available.

  1. If you would rather make your own organic soil, try this recipe: Volume for volume, add presoaked coco coir, coarse sphagnum moss, or peat moss to the depleted soil.
  2. Add vermiculite, perlite, or course sand until friable. Perlite increases the surface area for friendly bacteria particularly well.
  3. Add compost, bat guano, worm castings, blood and bone, or old mushroom compost to provide essential nutrients.
  4. Add crushed rock dust, dolomite, epsom salts, and molasses to provide a range of vitamins and minerals.
  5. Adding a splash of microorganisms to any soil mix is beneficial. Burgeoning colonies of beneficial root bacteria make plants hardy in the face of weather and disease, pests, and poor pH. They also help decompose old roots into beneficial compounds for new plant growth.
  6. Alternatively, old soil can be reused in other ways:
  • Add it to compost
  • Dig it into garden beds
  • Fill holes and divots in your yard
  • Add to the bottom of planting holes

Building higher-quality soil with organic matter reduces plant stress, improves disease resistance, and saves you money. Well-structured soil retains water, yet drains well and promotes a healthy root zone. This optimises healthy growth for the life of the plant. Add slow-release fertiliser pellets or water monthly with a liquid fertiliser like fish or seaweed emulsion. Regular maintenance means the soil will need less attention next time it is reused.

Improving old soil and then reusing it to plant or pot-up can save money and provide myriad benefits for the cannabis grower.

Honest Answers About Reusing Soil.

itsaplant
Active Member
shizz
Well-Known Member
asdewqasdfgh
Active Member
angryblackman
Well-Known Member

Don’t reuse soil! You can trust what comes out of the bag or you can mix the soil yourself.

Subcool, DoubleJJ, Dirttyd, and TMB have all posted their soil recipes in the past and you can add or subtract whatever you want to it. I personally will be giving DJJ’s soil a shot this season.

LT1RX7 Drifter
Active Member
LT1RX7 Drifter
Active Member

Don’t reuse soil! You can trust what comes out of the bag or you can mix the soil yourself.

Subcool, DoubleJJ, Dirttyd, and TMB have all posted their soil recipes in the past and you can add or subtract whatever you want to it. I personally will be giving DJJ’s soil a shot this season.

angryblackman
Well-Known Member
Sunbiz1
Well-Known Member

This a long re-paste, but worth the read:

Endless Soil Remixing with the 3LBS

We are about to go totally against the advice that Cervantes and Rosenthal and many others give concerning soil . . . the three_little_birds want to 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 . . .

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?”
Some “experts” will tell folks to throw out their soil after every grow . . . and we’ve known plenty of commercial growers that happily comply 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 spending something like $20 for a bag of FoxFarm soil rubbed us wrong . . . our indoor herb grows have evolved to use 2’x3′ containers . . . so with our container system it might take 2+ full bags of that soil for 3 plants in one of those containers . . . The three_little_birds wanted to save our money to purchase top quality genetics . . . not to buy simple dirt . . . so we decided there had to be a better way!
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 . . . we 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 often have “top-dressed” with fresh mushroom compost as well . . . after a couple years of experience with mushroom compost . . . we’ve found it to be a great source for an indoor soil base . . . and it’s proven to work well with remixes . . .
Now we’ll walk you through a description of the soil building process . . . lets imagine we started with an already amended soil mix like FoxFarm Ocean Forest as the base . . . perhaps mixed � and � with mushroom compost and added perlite . . .
Once through it’s first grow (the plants fed only 100% organic with earth juice, guano and alfalfa 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 is our standard) . . . These container’s are longer than our 2×3 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, alfalfa (or 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 pearlite 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 . . .it’s not too hard to throw in an extra cup or two of the appropriate organic supplement . . .for example we’d add extra Blood meal or alfalfa for N – Bone meal for P – kelp meal for K and other micro nutrients . . .
A nice full 16 oz plastic “dixie” cup of each of the prior mentioned ingredients would be our “baseline” for supplementing this round of soil re-mix. . . that actually equals a measurement of 2 cups (1 pint) . . . 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 the soil. . .
Now we will wet this whole mix down lightly and let it “cook” for a spell. . . We have a couple of 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 or shut-downs 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. . .

Now for the second grow . . . 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 some of 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 . . .

As an example of this technique . . . 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 alfalfa / blood meal would be added. . . If yellowing has occurred then a nitrogen supplement is added again. . . as we’ve gotten more adept at remixing our soils . . .

Just as a note about nitrogen sources . . . we’ve found that over time we can now judge better how much of the amendments to mix in from the beginning . . . and as we’ve increasingly switch from blood meal to alfalfa . . . we’ve found that we can add alfalfa meal with every soil remix . . .

Kelp meal is always 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 usually be necessary again too . . .and it’s possible your soil will need even more lime 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 result was that 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 was designed to be 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 from here we simply continue adding amendments by feel as needed. . . as we’ve already described . . .

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 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 . . . folk who have checked out our picture gallery at CW 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 now has been remixed double digit times . . . has NEVER been flushed!
one more 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 . . . 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 . . .

As a final note . . . we are proud to report that earthworms live in our soil remixes now. . . not the big fat nightcrawlers 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 . . .

So after talking with 8 different hydro shops that all sell soil I think I got the best answer.For obvious reasons hydro shops want you do buy their soil…