Some of you know that I love to chase down the sources of horticultural beliefs. If you have ever spent time on any plant forum you know the common advice is to keep your plants root bound, or at least when you repot give the roots only an "extra fingers width" on each side the pot. My question is where did that advice originate? Why do we believe it? Is this really good growing advice or just an old wives tale? Are plants in the rain forest root bound?
I understand that nursery men prefer to start their plants in small pots and allow the roots to fill it before stepping the seedling up to a larger pot. My understanding is they do this in order to encourage a hearty root system first. But it appears some growers may have taken this advice to excess and always keep their plant's root bound. Should we always keep our aroids in pots so small their roots are for ever crowded, or give them space to grow?
We always have new growers looking for good growing advice. If you have adopted a small pot policy please tell us why. If you are an experienced grower and prefer a tight pot method I would enjoy knowing the reasoning. Many of you don't know that I have written for years for a variety of magazines and I have another train of thought in this area. I am now working on a new article to explain about aroid growth, a plant's need for oxygen around its roots as well as how to keep their root systems healthy. This discussion will help me to formulate my article.
If you are new to growing, please chime in.
By the way, I'm mostly here to listen. I just want to know what others believe and why.
Thanks!
Steve
www,ExoticRainforest.com
This message was edited Sep 2, 2010 7:56 PM
Root bound. Your input please.
Hi Steve. I have heard that advise too over the years. I personally have never followed it. I don't like mine to be pot bound. I know they say that about epis too but even mine have room to grow and still have flowered for me. Now... the extra fingers width on each side could logically be a good rule of thumb for those who are new to pot culture. That would be one way to ensure they would not over pot something. Just my 2 cents.
I have to agree these are safe rules for the home grower to use. This does not work with some plants some plants love free roots to run and many trees will bind up if kept in to small a pot for long. For the most part plants grown in containers these rules would be very useful.
I have always looked at this situation in two ways; pot-bound and root-bound. Pot-bound being where the roots have filled the soil and root-bound when the roots reach the point to where they become so thick they begin to choke themselves. There's a fine line between the two. I've never been a fan of pot-bounding. My thoughts are, the more the roots can spread the more nutrients can be taken in without depleting the soil. If the pot size has reached a maximum that can easily be handled then root pruning takes the place of repotting to a larger size but this can put a halt on plant growth while and until it strengthens its root system.
There are two different types of pots available that will keep roots in check by chemically root pruning with copper as the roots reach the inside of the pot surface. Plants will not produce the heavy roots that circle the pot but a more fibrous root system within the soil. It's the fibrous roots that uptake the nutrients. One type, Spin Out, has the inside coated with copper hydroxide. The other, Root Right, is impregnated with copper chloride. There are pluses & minuses with either of these. The coated pots produce plants that are less root bound than the impregnated ones. However, some coated pot grown plants can continue to show root suppression even after being removed from the pots. The impregnated pots are less efficient than the coated but more than non-coated. Neither is a permanent fix to pot bounding, though. They will extend the time before having to repot by a few months.
My thought has always been in line with Steve's question - unless it grows within the cracks of rocks, when is a plant root-bound in the wild?
Steve S
Of course, on a humorous note, if "homeward bound" means on the way home, then pot-bound means on the way to being planted in a pot, Or it could mean you are looking for something else . . .
:)
LariAnn, you know you are "nuts" but you also know I love you dearly!
Let me start with this is not particularly light reading so many will find all this technical and boring. I post it because a few are interested as am I. This is not directly related to my question but is a part of the larger interesting I have in how plants grow in the rain forest versus our homes.
Steve, I thought you might enjoy reading this note from my friend Ted Held. Ted is a chemist as well as a serious plant nut. It, along with some reading I have been doing in the past week from the works of Dr. Nalini M. Nadkarni who is known as the "Queen of the Canopy" and have learned quite a bit from her papers. It does appear epiphytic plants find a way to absorb nutrients in the canopy without necessarily drawing them directly from the host tree which explains some of my original queries. She also has some excellent complete lectures that can be seen on the net. You can find them by typing in her full name with the ending "PDF".
"Most plants with leaves have the ability to redistribute nutrients to
other tissues as those older leaves become senile. The redistribution
is not complete, however. I have figures for this, but I think it runs
about 50% or so being reabsorbed, the balance remaining locked in the
old leaf tissue.
Of course, then the old stuff falls off and the decomposers come into
play. Eventually these will get all the rest of the goodies out and
make them into tissues of the decomposers.
What this means is that there is a small amount of material available
to epiphytes that does not involve parasitism of the host plant. Since
80% or so of terrestrial plants form micorrhizal associations with
microorganisms (mainly fungi) around their roots, one is probably safe
to assume that the decomposing mats of vegetable matter lodged in tree
crotches yield part of their nitrogen and other nutrients through the
microrrhizal organisms to the epiphytes in return for certain sugars
and other compounds exuded by the roots of the epiphytes and absorbed
in turn by the microorganisms. This is true symbiosis.
Mycorhizzal associations are triggered in nutrient-poor environments.
If epiphytes are adequately nourished they tend to treat micorhizzal
organisms as enemies.
The bark material probably contains very little nitrogen by itself,
mainly consisting of structural polysaccharides like cellulose and
lignin. Not very nutritious, I expect. Of course there will be goodies
in the conductive tree tissues deeper within. But then the feeding
plants would be parasites and not epiphytes.
There is also a possible dimension, especially in wet forests, where
some microorganisms, such as blue-green algae, also act as nitrogen
fixers. This means that they manufacture "fixed" nitrogen (as ammonia,
nitrates, and nitrites) from the air. This mechanism is a huge source
of nitrogen fertilizer in bodies or water (like the ocean). But maybe
this can happen also on a wet tree limb. There are other nitrogen
fixers throughout the biosphere. Maybe those contribute to the ecology
of rain forests. All these guys release their fixed nitrogen when they
die. It takes a few cycles for it to return to atmospheric nitrogen
again.
Ted Held."
The more we understand the rain forest the more we learn about growing our own plants. I guess that's why I keep my nose buried in some "over my head" paper so often.
Good growing!
Steve
PS: I'm anxious to visit with you next weekend LariAnn!
This message was edited Sep 10, 2010 5:32 PM