Hello Folks - I have several large containers used [in an attempt] to grow one tomato plant each this spring. Due to weird temperature fluctuations [not to mention my limited ability as a tomato farmer], they never really produced anything.
So - - - now I have all these large containers of used potting soil that had been amended with guano and worm castings as well as some perlite for air and drainage. A bit of an investment to just toss under the rose bushes now.
Do you folks re-use potting soil in containers or do you only recycle it into the garden?
Second Generation Potting Soil
I know many users recommend dumping each year but I agree this is an investment. These tomatoes are growing in a potting mix that I have use 3 years now. I do put a little new potting in to fluff up the volume of the mix each time I plant, I don't mix fertilizer into the mix I use a strip of 10-10-10. I wonder if your problem with tomatoes may be too rich a mix in your boxes, even though guano and worm casting are organic aren't they very high in nitrogen?
Some basic "troubleshooting" questions:
1. did your large containers have holes to allow proper drainage? Many containers, including half barrels as well as purpose-built planters, are sold without holes so you've got to drill your own or punch out blanks. If water builds up in your container --even if you don't notice it, as has happened with some of mine in the past, with the surface seeming dry, but 2-3 inches below waterlogged-- the root zone will end up being way too shallow.
2. Guano and work castings are great --but must be part of the right overall mix, and the other components are more important. "Some" perlite may not be enough, for example --you'll see recommendations that it be a full one-third of the total mix. I've found that fine pine mulch does more for my mix than anything else --again, can be as much as a full one-third of the total.
Read the stickies in this forum, they may apply to your situation.
I generally wouldn't reuse potting mix, but since it sounds like yours is only a few months old it would be less of a problem than if it was a year or two old. So unless the tomatoes died of some disease I think you'd be OK. I do have some concerns about the amount of guano and worm castings though--things like that can decompose quickly and collapse your soil structure much faster, so as JPlunket suggested I would recommend reading the stickies before you plant anything else and decide if you think your blend is really a good mix for containers or not.
That would be my suggestion as well. When you start adding all the goodies your sure plants are going to need, you can easily overdo the amount of fine material in the media. Fine material clogs air pores and adds to water retention. The worm castings & guano add nothing you can't get in a single soluble fertilizer application, which will do nothing in the way of altering soil structure.
Adding perlite to a soil that is composed of too many fines generally does nothing to help with excess water retention and improve drainage. It does actually sort of reduce the volume of soil available for fine root colonization, but it would have to be a huge % of the soil to make an already water-retentive soil into a well-aerated soil that drains well. For a clearer illustration of what I just said, ask yourself how much perlite would it take to make a bucket of pudding into something that is well-aerated and drains well and you'll see how the perlite may not have helped at all.
Al
That's an incredible tomato Gessie, how tall is it? RE: my tomatoes.....it's Phoenix. The growing season is so short due to high temps. The plants just got started and we hit triple digits in May. Then June cooled back off to unseasonable low's (80's) now we are back to normal triple digits. Projected to 110 today. Those tom's had no chance. The only ones that produced were cherry types.
I'll fluff up the older soil with some new, I'm repotting some coleus, a Rodney's Aster and other ornamental types. I have always added a bit of perlite to the mix, maybe 25% or less. The worm castings and guano were just a recent after-thought.
Thanks for the info. I'll check the stickies. That's a good idea.
Edited due to cross-posting.
This message was edited Jul 5, 2009 8:21 AM
The tomato plants (not incl the earth box) are 9 ft tall. I actually just measured them this morning to settle a "disagreement" with my wife. She was right of course,( I had said 10ft) LOL We're complaining about 97 degrees here. Think I'll just hush in light of your situation. Course, we're always told "Yes, but they have a different kind of heat out there." Seems to me hot is hot.
The state motto: "Yes, but it's a dry heat."
It is a bit easier to take than a humid heat. My DH's family is in Huntsville, Alabama and when I stepped off the plane there one August day I never dried out again till I left. Jeez, it was miserable.
We just get our work done early morning and late evening. Catch up on indoor tasks mid-day in summer. And escape to the high country whenever we can. Here's a pic from last summer, DH relaxing in a nice juniper tree, elevation at this campsite is about 7,000'. We're heading off for a week at of swimming and fishing soon.....9,000' this time.
gessieviolet:
Don't the Earthbox directions say you can reuse the same soil for up to 5 years? By the way, what did you grow in that EB soil the first two years?
I am growing a tomato plant in a large pot that held flowers last year. The plant is huge and seems to be thriving. Also, bush beans grown in (even second year) potting soil seem to flourish for me.
Denise
In my estimation, the only case to be made for reusing container soils is one of economics, and you'll never find me argue against making that decision. If you can't afford fresh soil, you can't afford it. That said and setting economics aside, you might decide to reuse soil for reasons other than economical. Perhaps the effort involved with acquiring (or making your own) soil is something you might not wish to go through or be bothered with.
In any case, it would be difficult to show that soils in a more advanced state of structural collapse can somehow be preferred to a soil that can be counted on to maintain its structure for the entire growth cycle. So, if the economic aspect is set aside, at some point you must decide that "my used soil is good enough" and that you're willing to accept whatever the results of that decision are.
All soils are not created equal. The soils I grow in are usually pine bark based & collapse structurally at a much slower rate that peat based soils, yet I usually choose to turn them into the garden or give them over to a compost pile where they serve a better purpose than as a container soil after a year of service. Some plantings (like woody materials and some perennials) do pretty well the second year in the same bark-based soil, and with careful watering, I'm usually able to get them through a third year w/o root issues.
Watering habits are an extremely important part of container gardening. Well structured soils that drain well are much more forgiving and certainly favor success on the part of the more inexperienced gardeners. As soils age, water retention increases and growing becomes increasingly difficult. If your (anyone's) excellence in watering skills allows you to grow in an aging medium, or if your decision that "good enough" is good enough for you, then it's (your decision) is good enough for me, too.
The phrases "it works for me" or "I've done it this way for years w/o problems" is often offered up as good reason to continue the status quo, but there's not much substance there.
I'm being called away now, but I'll leave with something I offered in reply on a recent thread:
"... First, plants really aren't particular about what soil is made of. As long as you're willing to stand over your plant & water every 10 minutes, you can grow most plants perfectly well in a bucket of marbles. Mix a little of the proper fertilizers in the water & you're good to go. The plant has all it needs - water, nutrients, air in the root zone, and something to hold it in place. So, if we can grow in marbles, how can a soil fail?
Our growing skills fail us more often than our soils fail. We often lack the experience or knowledge to recognize the shortcomings of our soils and to adjust for them. The lower our experience/knowledge levels are, the more nearly perfect should be the soils we grow in, but this is a catch 22 situation because hidden in the inexperience is the inability to even recognize differences between good and bad soil(s).
Container soils fail when their structure fails. When we select soils with components that break down quickly or that are so small they find their way into and clog macro-pores, we begin our growing attempts under a handicap. I see anecdotes about reusing soils, even recommendations to do it all over these forums. I don't argue with the practice, but I (very) rarely do it, even when growing flowery annuals, meant only for a single season.
Soils don't break down at an even rate. If you assign a soil a life of two years and imagine that the soil goes from perfect to unusable in that time, it's likely it would be fine for the first year, lose about 25% of its suitability in the first half of the second year, and lose the other 75% in the last half of the second year. This is an approximation & is only meant to illustrate the exponential rate at which soils collapse. Soils that are suitable for only a growing season show a similar rate of decline, but at an accelerated rate. When a used soil is mixed with fresh soil after a growing season, the old soil particles are in or about to begin a period of accelerated decay. I choose to turn them into the garden or they find their way to a compost pile.
Unless the reasons are economical, I find it difficult to imagine why anyone would add garden soils to container soils. It destroys aeration and usually causes soils to retain too much water for too long. Sand (unless approaching the size of BB's), has the same effect. I don't use compost in soils because of the negative effect on aeration/drainage. The small amount of micro-nutrients provided by compost can be more efficiently added, organically or inorganically, via other vehicles.
To boil this all down, a container soil fails when the inverse relationship between aeration/drainage goes awry. When aeration is reduced, soggy soil is the result, and trouble is in the making."
Al
Al, thanks for a very interesting discussion of reasons for using new mix each season. I am well aware of the facts, but understood the OP to simply be asking. Do you folks re-use potting soil in containers or do you only recycle? Since I do, guess I should have simply said "yes" rather than appear to be an ignorant hick.
("in my estimation, the only case to be made for reusing container soils is one of economics, ........... If you can't afford fresh soil, you can't afford it.") you reply.
Many of us do this as a hobby, experimenting, defying the rules just to see what will happen, does that make us more economically challenged, less educated or lazier than others? I, for one, think not! Who said: "When others ask "why?", I ask, "why not?" You have offered excellent reasons why it is done in a certain way, but surely you must realize, others do it differently (ignoring facts) and get excellent results.
Lane
Al, Thanks for taking the time to provide so much interesting data! I feel like I know a lot more about container growing now.
For the record, it's partly economics......but mostly it's just not wanting to be wasteful....which is [in a way] economics. The tomato containers have only been in use a few months, the plants failed but probably not due to the soil so much as other enviromental factors.
Like Lane said, I do this as a hobby, am fairly successful growing 'houseplants' in containers, even if the houseplants live on my patio. I recently discovered Ocean Forest potting soil and perfer it to Miracle Grow. It would be nice to 'make my own soil' but time is the biggest factor right now. Do you chip pine bark to make your own soil? What else goes in? Is this info in the stickie?
Mary - Yes, Tapla goes into great detail on how he creates his soil on the stickies. Even if you don't want to make your own soil, it's an interesting thread to read and well worth the considerable time you'll spend reading it.
GV seems to assume that I was addressing her; or, she has taken it upon herself to be the forum's voice. There was nothing personal in anything I said, and I wasn't trying to be critical of her, only offer observations some might find value in.
I grow as a hobby as well, but I'm old enough to have learned that simply because someone wishes to expand their horizons, experiment, and defy (whose - certainly not mine) rules is no reason to believe the results are necessarily going to be favorable; nor can the wishes be logically used as sufficient justification that others follow the clarion call. I may wish to drive w/o a seatbelt, but is it wise to risk injury or fines so I can say I did it my way? I suppose it is if I have a point to make about seatbelt laws, but that's an argument with no end, so why debate it? Should I, if I choose to go beltless, suggest others do the same? What if I point out 'It works for me' as a weighty point?
The consideration can be distilled to the question: All else being equal, is it more likely my plants will do well in a fresh and well aerated soil, or in a used soil on its way to collapse?
I never suggested that you can't have excellent results growing in old container soils. 'Excellent' is a subjective term, so if I'm comparing my good results to my mediocre past results, I may feel that things are excellent, while you observe my mediocrity with a raised eyebrow - subjectivity. The same applies if our positions are reversed.
I'm not trying to get anyone to change anything if they are rigid in their ways. I have no stock in anyone else's plants, but I do have an interest in trying to help those who wish to view different perspectives, regardless of minor disagreement. The forum is bright enough to weigh the merit of individual arguments, but I think 'it works for me' leaves tremendous room for the possibility of improvement.
Yes, Mary. I do make all my own soils, and haven't used a bagged or commercially prepared soil for 15-20 years. I'm fortunate enough that I have several near sources for bark in various sizes and ages (fresh to partially composted to well-composted). I never waste the old soil either, and understand the urge to be responsible with resources. It usually goes directly into the gardens or beds, or sometimes I'll turn it into the compost pile. It depends on what the soil is made from.
All my veggies and floral display containers are grown in a mix of approximately
5 parts pine bark fines
1 part sphagnum peat
1 part perlite
+ lime
The picture below is what I grow all my woody plants (mostly material I'm growing as bonsai or growing on for bonsai) and houseplants/succulents/cacti in. It's easy to see that I place a high premium on soil aeration and longevity.
Take care, Mary.
Al
Wow Al - that does not even look like potting soil! ;~) Very impressive. And here I was patting myself on the back for 'upgrading' to Ocean Forest from Miracle Grow.
Thanks again for sharing your knowledge, it's appreciated.
Mary
Tapla,
Thanks for the usual excellent guidance.
Your pictured mix --what's that recipe?
Back on the recycling points. To me the issue of soil life is most important as related to large, "permanent" potted plants. To repot them with any regularity is an enormous effort. Moving to larger an larger pots becomes a major capital investment, past a certain point. More and more soil is held by the root mass, which makes for less actual soil replacement in a re-potting. And as the plants grow larger the anchorage aspect of the soil becomes more important, which seems to me to argue against fresh soil, in favor of a more rigid soil.
In that context --forgive me if I'm asking you to repeat yourself-- is there a particular soil mix for very large plants, in "installation" pots, and perhaps a related special watering/feeding regimen, that would allow a gardener to treat the soil in the pots as permanent, "never" needing new soil ? I get your point about the marbles working if water and nutrients are perfectly controlled --that would be a permanent soil. I am also recalling recommendations I've read to use exploded granite or medium size lava rock --long-lived, just like marbles-- as a major soil component, to extend its life.
For pots that one can't change over often (or ever), without major help or major budget, what do you recommend in terms of mix and water/feeding?
And to what extent should one try to remove root-held soil when changing over a very large potted plant? say, a 9 foot tall oleander in a 25 inch pot.
This message was edited Jul 8, 2009 10:39 PM
I'll be happy to answer if it's ok with Mary? I'm afraid I've already offended one, & don't wish to add another to the list. ;o)
Al
Al, don't worry about it. Go man!
The recipe is:
1 part uncomposted pine bark (1/8 - 1/4" pieces)
1 part screened Turface or NAPA floor-dry (Turface preferred)
1 part crushed granite or cherrystone (chicken grit)
gypsum
I think that particular soil has a little coarse silica sand (1/2 BB-size) and some vermiculite in it, too
First, let's make a distinction between between repotting and potting up. Repotting includes root pruning and a complete or near complete change of soil in the root mass, while potting up is simply increasing the amount of soil surrounding the current root mass when you move it to a larger container. Potting up can be done at any stage of the growth cycle, while repots of tropicals are best undertaken in the month before you expect best growth, and temperate plants just before bud movement in spring.
Reason, logic, and eventually, practical experience will show that plants grown with their roots continually and fully confined within container walls, and only potted up instead of being repotted are living under a death sentence and destined to live with reduced vitality (inability to grow to their potential genetic vigor) until the organism eventually dies. Strong words, yes, but as plants grow, so do their roots. They twist and turn around each other and strangle themselves. Organic soils break down into increasingly smaller particles and hold too much water in the lower parts of the container for good root metabolism, and eventually calcify and become hard as stone, adding to the problem because cambial tissues cannot expand sufficiently to ensure adequate water/nutrient transport. Total soil volume in relationship to plant size is continually reduced until fewer and fewer new roots are available for water/nutrient uptake. Lack of branch/stem extension is a first symptom, followed by a reduction in foliage mass and fruit/bloom production as plants weaken. Slowed metabolism also means lowered production of various anti-feedants, anti-metabolites, and toxins that make insects and bio-pathogens feel pretty unwelcome. In short - the plant struggles, and even if it LOOKS like it is growing with good vitality, plants with roots that are too tight are losing out on varying degrees of potential growth and vitality.
Anchorage is only a temporary issue. Once the plant, even large plants, have established in the container, the worry is usually more about toppling than actual anchorage. Large, anchoring roots are actually pretty useless in containers, serving only as water transport organs while taking up valuable space that would better be occupied by fine roots.
Soils for long term plantings should have a very high % of mineral components (not topsoil or garden soil, though). I limit all my long term soils to no more than a 1/3 organic (bark) component, and some soils I use have absolutely no organic material in them. The lower organic component ensures longevity. The soils I use for long term plantings will always remain perfectly serviceable long after it is prudent to extend the interval between repots.
There can never be a plant that lives in the same soil indefinitely and exhibits growth at even close to its genetic potential. The difference between most of us and our revolving door houseplants that 'need replacing' every few years and the beautifully healthy bonsai trees maintained in tiny containers is attributable to one thing - attention to the root/soil relationship. Bonsai trees have the unnecessary thick roots removed and the soil replaced at regular intervals, and they are passed down through generations of owners, while most of what we consider long term plantings are lucky to see their 3rd birthday.
A 9' oleander in a 25" pot probably shouldn't BE 9'. If the grower was practicing rejuvenation or maintenance pruning, there would be 9 stems on the plant & 3 would be cut back to the trunk each year after blooming. It's likely that I would be able to take the oleander out of the 25" pot, prune it, reduce the roots, and return it to you in an 18" pot where it would be happy for a number of years before repeating the process. You could then use the 25" pot for something big. ;o) (teasing a little here, but good naturedly, so don't take offense, please).
I think I hit most of your points, JP, but if there's something I missed, please don't hesitate ....
Thanks for the floor, Mary.
Al
Al,
Nice mix and Qs well covered, thanks, except for the one about lava rock --is it a suitable substitute for the Turface or the granite in your mix, or none-of-above?
As to a given section of working roots, function is transitory --as roots age, their function changes from absorption of water and nutrients, to a simple transport function. Ultimately, in a given volume of soil, "old pipes" crowd out "new intakes" --steadily reducing the margin of error for watering and feeding.
The fallacy at work in my own mind is "permanence". In point of fact, I've not kept plants for more than 3 to 5 years, though I think of them as permanent. Learning from you here that good bonsai culture requires cutting out large "pipes" every so often, makes the whole thing easier for me to grasp and accept.
Thanks again.
I was just having a similar conversation on another forum. The lava rock is somewhere in between Turface & granite, so it reduces the ease of adjustability. Here's how the other conversation went:
He: "..... you mention that the scoria (lava rock) and haydite (expanded shale) do not contrast nearly as much as Turface and crushed granite. -- is that a bad thing? will less diversity compromise a soil mix?"
Me: Not really. It just makes it so much easier to adjust the water retention of the soil if you have something like Turface or floor-dry with tremendous internal porosity and water retention to contrast with a product like crushed granite which has no internal porosity and very little water retention. E.g., a soil with
3 bark
4 Turface
2 granite
would hold much more water than
3 bark
4 granite
2 Turface
When there is little contrast between the ingredients, it makes for more guesswork, but I suppose that if you get used to what you're using, adding/subtracting ingredients to achieve your desired level of water retention will become second nature.
In almost every case, the (relatively) small plants we keep in containers don't need the big pipes & anchors. The finer roots are adequate to anchor container plants in the soil, and since the feeder roots are bifurcations of larger roots, the larger roots will ALWAYS be adequate for any hydraulic transport furnished by their smaller workhorse counterparts. A tree in the ground that is 20' tall might need several 6-10" thick roots to anchor it, but a plant with 1/1,000 the mass needs only roots large enough that they won't break in a breeze (1/8-1/4" for a sizable tree). Tiny roots rock! ;o)
Take care - good growing. ;o)
Al
Got it, thanks! Now I need to find a source of Turface or a similar product in Puerto RIco.
Love the picture Al and thanks for all the great info you provide. I've started reading through the sticky and must say you have put lots of effort and energy into helping us mere mortals try to garden! Your time and efforts are appreciated.
Thank you for the kind words, Mary. ;o) I get a good deal of personal satisfaction from the thought I might be helping someone. I look at my time here & on a couple of other forum sites as an extension of my growing hobby. I find that plant people are generally very gentle & fun to be around. ;o)
Come say "HI". http://davesgarden.com/community/forums/t/1012895/
Al
I'm so glad I stumbled across this discussion. I now understand why my poor container rose bush died this year, particularly this morning after I dug it out of the barrel.
I really don't have a good place to grow roses outside of a container. Al, do you have any suggestions for what mix might be suitable for a rose bush in a half-barrel? (apologies for the thread hijack) :-(
The one I just described would be VERY suitable for anything woody. Roses would love it.
Al
You mean this one?
"3 bark
4 Turface
2 granite "
No, this one:
By volume
1 part screened (1/8 - 1/4") uncomposted pine or fir bark
1 part screened Turface
1 part crushed granite (grower grit or #2 cherrystone)
Al
Thanks so much, Al. Think I'll try that mix out on some of my miniature roses, too. A friend is getting me a relatively expensive rose this fall and I'd just as soon not kill it off!
I LOVE your frogs!
Even if they're mooning you? Look closely. ;o)
Al
:-)
Talpa...I know your probably weary of discussions on soil. If you wouldn't min one question? Can one substitute clay based kitty litter for the Turface? I bought Turface from a local Bonsai seller but the cost is prohibitive for the amount of pots and sizes that I have for vegetables and ornamentals. I have read on the internet that Aquatic soil, Turface and kitty litter is basically the same product. Thanks in advance for your respected opinion.
Profile Corp packages Turface MVP as aquatic soil for a number of entities, so it's fine to use those products. I'm not sure if they still package 'Soil Conditioner' for Schultz, but it is/was the same product.
All kitty litter is not created equal. Some is fired at much higher temperatures & some is pelletized or prilled bentonite & (re)turns to muck when it's wet. Test your product by freezing some solid in a plastic cup of water (overnight). If it comes through intact, it's ok for soils.
Size is very important in choosing materials for soils. At around a 1/8" particle size, the material stops holding water in interparticulate pores, so you want most soil particles from just under to just over 1/8". Large particled material like Espoma's Soil Perfector or Permatill are less desirable than finer material.
A suitable substitute for Turface is a calcined DE (diatomaceous earth) product by NAPA (auto parts) called floor-dry (not to be confused with powdered DE. It;s fired in an oven and looks much like Turface (size).
That cover it? ;o)
Al