Botom heat and plant physiology

I have a indoor heated propagation case and a hot frame, but I have to admit I don't understand the principal behind them other then it is bottom heat. Well, I do know that seeds love botom heat to germanate, but my interest in is cuttings (would love to try vegitave but equipment cost/space is a bit prohibited in my "lab").

So from what I've read, and hear, roots grow best at cooler temps of 60F, which is a bit cooler then my indoor propagation case when ventilated and unplugged. So I'm questioning why the heat? Is the concept warmer soil say 70-80-90 and cooler air say 60? I know when I crank up the heat seeds will pop in a day but my interest is what is ultimate for cutings. The propagation case is strictly inside, so the air temp is 70 (I can live cooler but sorry to say the wife can't). I grew up with a basement full of hot frames, conveniant yes, but more for the cool temps.

The hot frame can go outside for winter (current thought) where I can acheive cool air temps and warm soil if that is the ideal ... or indoor under lights as a cold frame if that is ideal. I rather uncertain as I lack the technical knowledge.

So I guess I need a primer on plant physiology too fill in the knowledge gaps. It seems to me that IBA is a growth inhibitor that then forces concentration on root growth, while other hormones promote vegitative growth (undesired?) or in combination as some ballance. But I need to understand plant physiology in nature for understanding and then I can apply it. So then, do roots grow at same time as vegitation or alternate (growth then roots) ... or root more in winter (or truely dormant), growth in summer? It is easy to understand vegitation, we observe it, but roots are rather abstract. Anyone point me in the right direction?

 

My (admittedly limited) understanding is that the differential of top and bottom temps is one of the key factors. The idea is that the roots will develop and the tops will not (at first) until the roots have reached the point where they will support the top growth. This is the same reason why we cut back the top growth when rooting cuttings. With grapes, the higher temp promotes the formation of "callus" which is un-differentiated tissue, from which roots can be generated. I assume there is a parallel process in other plants.
Ralph

 

I think your right ... and callus formation is required as a purcurser to roots. I understand that in micropropagation they generate callus that is broken into particulates which whole plants are grown in mass. kinda like growing hair on a cue ball = amasing. I'm not sure lower plant forms like mosses form callus, but I suspect most all plants must develop callus do to be vegitatively propagated.

And I suspect my question is a bad one in that all plants are different such that nothing is universal, hence, different ideal surface and ground temps for propagation of types. But I was hopping there was some magic formula of ideal soil and air temp ... or that someone could point me to a study on the temprature and root formation. Or is root formation is continious or stages. Lots of info out there, just can't find exactly what I'm looking for yet.

 

Is there a specific plant or plants that you want to grow
from cuttings? Bottom heat comes in real handy for
certain hardwood cuttings to aid in the formation of
roots. I am not so sure you are looking for a primer
in Plant Physiology as knowledge of that subject
alone will not help you that much in attaining roots
to grow from selected hardwood cuttings from Japanese
Maples, Magnolias, Michelias, certain Camellias and
other plants.

Let me really mess you up. Years ago we used IAA
to aid in producing a callus but we used IBA to help
us produce a thallus. There really is no right or wrong
when we may want to utilize plant hormones as they
can be interchangeable at times for us. As an example,
the old rooting powders had IAA as their main active
ingredient. Now we see rooting powders that have
IBA in them instead. One of the reasons why is that
IBA is less sensitive to light than IAA is meaning with
the latter with too much light we may lose some of the
effectiveness of the IAA. One thing for sure that if we
want to work on a root system it may be advisable to
have some EDTA also in the mix. NAA has been a
standard partner for root production also.

The problem you may face is that some of the older,
research was taken down off the internet years ago
and some of the more important studies were not
ever posted on the internet. If you are serious about
experimenting with plant propagation then I suggest
you get a copy of either book below.

This book does assume some prior knowledge in
plant science, regardless of the edition. My copy
of it is the 4th edition.

Plant Propagation: Principles and Practices
by Hudson T. Hartmann, Dale Kester and in
some editions others.

As a companion book you may want to consider this
one.

The Reference Manual of Woody Plant Propagation: From
Seed to Tissue Culture : A Practical Working Guide to the
Propagation of over 1100 Species by Michael A. Dirr

For an overview of plant functions and an intense read
sometime look up this book.

Plant Biochemistry by James Bonner and Joseph E.
Varner.

Not all of the links are functional now but through
the links that are working you can get around well
enough to browse a host of plant propagation related
sites from here.

http://www.ipps.org/index.asp

Just to add food for thought. A nurseryman I knew,
now deceased, used an IAA paste for all of his air
layering. He would make a lengthwise slit in the
bottom of the branch or stem depending on which
plant he wanted to reproduce and then would cover
over the cut with his handmade paste. A leading
Citrus grower I know uses bottom heat for all of
his Citrus grafts in a temperature controlled room,
about the size of a standard lab at most Universities.

Good luck,

Jim

 

Thanks ... the biochem book sound what I'm really looking for but I really should have the others anyway so am heading off to book store as I speak (good deal on them at Amazon though!)....

 

The recommended books are great. You'll learn a lot.

But, there is a wide latatude in porpagating proceedures I've found. So don't be afraid to try stem cuttings. Bottom heat isn't really needed for most plants.

I kind of get the impression that you have this "toy", a bottom heater, and you've almost forgot that the idea is to propagate plants. not play with bottom heat.

I say that with sympathy because I react exactly the same way to a new gadget. I played with my bottom heater for a long while before I concluded that it's more trouble than it's worth.