Subject: Starting a new year...

From: "Robert S. French" <[email-masked]>
Date: Sat, 10 Apr 93 18:42:16 -0700

Well, for what it's worth, I've started my hydroponics garden for the
year.  Over the winter I cleaned it out and sterilized it with
chlorine, so hopefully the plants will be happier this year.  So far I
have planted 9 Burpee's Breeder's Choice yellow corn and two Ace
tomatoes.

The local tap water has a pH of 9.2, so I'm using MirAcid as my
nutrient.  This brings it down to around 7.5, which isn't TOO bad.
Maybe I'll try a mild acidifier (like General Hydroponics' "pH Down")
if I have problems.

			Rob

From [email-masked]  Ukn Jul  8 14:55:11 1993
Date: Thu, 8 Jul 93 11:51:54 -0700
From: "Robert S. French" <[email-masked]>
Sender: [email-masked]
To: hydro@hawg
Subject: [[email-masked]: Re: subscribe...ok...]
Status: RO

Please be sure to send messages intended for the entire list to
[email-masked]...thanks.

		Rob

----- Begin Forwarded Message
From: [email-masked]
Subject: Re: subscribe...ok...
To: [email-masked] (Robert S. French)
Date: Wed, 7 Jul 1993 22:21:19 +0000 (GMT)
In-Reply-To: <[email-masked]> from "Robert S. French" at Jul 7, 93 11:00:27 am

First to start a discussion we need to know what species are cultivated by
all others. Myself i dont produce but my job is to give advice to commercial
grower in greenhouse production and ofcourse in hydroponic production. i
think that hydroponic is the most chalenging production technic because
there is no place for mistake. we must control every element because a
slight variation can leed to big trouble very fast. But that production
technic is the one that produce the best result and the bigest yield.

I have to work with many vegetable crop and also ornamental plant. they are
produced in recirculated solution or lost solution. the latest is the one
that give less trouble. My main interest is in the solution control and i
try to find every information i can on how plant absorb fertiliser and how
one element can interfere with another one. Right now am looking to improove
fertiliser ratio for herbs, in order to get better yield without loosing the
taste, witch is very important. 

so what type of plant do you grow...

thanks

Claude 

----- End Forwarded Message

From [email-masked]  Ukn Jul  8 15:01:36 1993
Date: Thu, 8 Jul 93 11:56:55 -0700
From: "Robert S. French" <[email-masked]>
Sender: [email-masked]
To: hydro@hawg
Subject: Current status for this season
Status: RO

Well, so far my hydro gardening attempts for this season haven't been
so great.  For those of you who tuned in late, I have a large
fiberglass garden with an automatic recirc pump and 40 gal solution
capacity.  It recircs twice a day.  The garden is outdoors and not
enclosed.  This came with the place I'm currently renting, so I'm
guessing about how to use it.

So far, I have tried to grow corn and tomatoes.  I use a nutrient
solution consisting of MirAcid at recommended strength (the local
water has a pH of around 9.2, and MirAcid makes it almost neutral).  
The first batch of corn had a big problem -- the local cats kept
eating it.  So it never grew very tall.  It's now about 1' tall and
already producing tassels.  I just planted a new batch and will try to
keep the cats away this time.

The tomatoes usually do better, although their leaves tend to turn
yellow and curl up after awhile.  I imagine it's a nutrient imbalance
of some sort.

An interesting observation is that I drained the system and let it sit
for a few days with no solution running through it (I was too busy to
refill it).  The plants actually grew BETTER during this time.  So,
taking the hint that perhaps I was giving it too much nutrient, I cut
the dose by half with the next batch and so far the plants are growing
well.

			Rob

From [email-masked]  Ukn Jul  8 22:53:50 1993
From: [email-masked]
Subject: Current status for this season (fwd)...
To: [email-masked] (culture hydroponique)
Date: Thu, 8 Jul 1993 22:47:59 +0000 (GMT)
Content-Length: 2108      
Status: RO

 > Well, so far my hydro gardening attempts for this season haven't been
> so great.  For those of you who tuned in late, I have a large
> fiberglass garden with an automatic recirc pump and 40 gal solution
> capacity.  It recircs twice a day.  The garden is outdoors and not
> enclosed.  This came with the place I'm currently renting, so I'm
> guessing about how to use it.
> 
> So far, I have tried to grow corn and tomatoes.  I use a nutrient
> solution consisting of MirAcid at recommended strength (the local
> water has a pH of around 9.2, and MirAcid makes it almost neutral).  
> The first batch of corn had a big problem -- the local cats kept
> eating it.  So it never grew very tall.  It's now about 1' tall and
> already producing tassels.  I just planted a new batch and will try to
> keep the cats away this time.
>
To get more from your nutrient solution you should lower the pH to about 6.0
or most micro-nutrient wont be available to plant.

Water with a pH of 9.2 is probably full of sodium so you need to be carefull
when you feed the plant because too much fertiliser will raise the salinity
of the solution and even burns the root.
 
> The tomatoes usually do better, although their leaves tend to turn
> yellow and curl up after awhile.  I imagine it's a nutrient imbalance
> of some sort.
> 
> An interesting observation is that I drained the system and let it sit
> for a few days with no solution running through it (I was too busy to
> refill it).  The plants actually grew BETTER during this time.  So,
> taking the hint that perhaps I was giving it too much nutrient, I cut
> the dose by half with the next batch and so far the plants are growing
> well.
> 
> 			Rob
> 

For the tomatoes, it's probably because of a too high pH and the plant dont
get all micro nutrient it's need. Also at a ph of around 7.0, nitrogen is
less available and that's why you get yellow leaves after a period of time.

Normally if lower leaves turn yellow you need more nitrogen, if it's the top
leaves it's a micro nutrients deficiency. Could you tel more about your
yellow leaves. 

thanks,  Claude

From [email-masked]  Ukn Jul  9 18:03:03 1993
Date: Fri, 9 Jul 93 15:00:41 -0700
From: "Robert S. French" <[email-masked]>
Sender: [email-masked]
To: [email-masked]
Cc: [email-masked]
Subject: Re: Current status for this season (fwd)...
Status: RO

   From: [email-masked]
   Date: Thu, 8 Jul 1993 22:47:59 +0000 (GMT)

   To get more from your nutrient solution you should lower the pH to about 6.0
   or most micro-nutrient wont be available to plant.

Do you have a suggestion about how to do this?  My experience in the
past, with what little chemistry I know, is that the water is pretty
well buffered, and whenever I add an acid it simply precipitates out.
There is a product called "pH down" by General Hydroponics that I
could pick up and try.

How often would you suggest changing the solution?  There are 40 gal
of solution, and only 9 corn and 1 tomato plant growing in it.  Much
is lost to transpiration every day.  Is it sufficient to just
re-dilute it with tap water (and adjust the pH) or are nutrients being
lost at the same time?

   For the tomatoes, it's probably because of a too high pH and the plant dont
   get all micro nutrient it's need. Also at a ph of around 7.0, nitrogen is
   less available and that's why you get yellow leaves after a period of time.

   Normally if lower leaves turn yellow you need more nitrogen, if it's the top
   leaves it's a micro nutrients deficiency. Could you tel more about your
   yellow leaves. 

So far this year my leaves aren't yellow.  They were yellow last year.
It was, I believe, the lower leaves that turned yellow.  They would
also become dry and "crunchy" after a while.

			Rob

From [email-masked]  Ukn Jul 13 09:44:36 1993
From: [email-masked] (Claude Gelinas Agr.)
Subject: Re: Current status for this season (fwd)... (fwd)
To: [email-masked] (culture hydroponique)
Date: Mon, 12 Jul 1993 23:44:58 +0000 (GMT)
Content-Length: 3694      
Status: RO

>    From: [email-masked]
>    Date: Thu, 8 Jul 1993 22:47:59 +0000 (GMT)
> 
>    To get more from your nutrient solution you should lower the pH to about 6.0
>    or most micro-nutrient wont be available to plant.
> 
> Do you have a suggestion about how to do this?  My experience in the
> past, with what little chemistry I know, is that the water is pretty
> well buffered, and whenever I add an acid it simply precipitates out.
> There is a product called "pH down" by General Hydroponics that I
> could pick up and try.

to change the pH you have to find first how your water is buffered like you
say. The buffering capacity of the water is in fact the alkalinity or the
amount of bicarbonate and hydroxyde already dissolved in water. these
product will interfere with the action of any acid one will add to the
solution. To find the alkalinity level of the water, just use a tester kit
provided for swiming pool they are quite acurate and cost very few.
when you know the alkalinity of the water you just have to use a chart that
will tell you how much acid you need to add in order to break the alkalinity
and start to lower the pH. I'll send a chart for acid next day or as soon as
i have enough time.

Could you send me the technical information about the "pH down" product.
What type of acid is it. some are good for hydroponic and some dont.

> 
> How often would you suggest changing the solution?  There are 40 gal
> of solution, and only 9 corn and 1 tomato plant growing in it.  Much
> is lost to transpiration every day.  Is it sufficient to just
> re-dilute it with tap water (and adjust the pH) or are nutrients being
> lost at the same time?

normally you dont have to change the solution, but just add fresh solution
to refill the container. The only time you need to change the solution is
when there are some accumulation of ions such as sulphates SO4-- or sodium
that will raise the salt index and disturbe the plant nutrition. First to
know if you will need to change the solution very often you need to have
your water analysed for mineral and that can be done in any good water lab.

Each time you add new water you must add nutrient but during summer month
when transpiration is very high, the solution must be more diluted then
during winter. Normally during summer we use half strainght solution. That
prevent salt build-up. The pH must be adjusted each time and some time also
when you dont add a lot of water. that is because when plant absorb some
nutrient she exchange it with an H+ ions that will lower the pH of the
solution. if your pH tend to drop after few days, this is because you use to
much of ammonium nitrogen in your solution. Replace it with nitrate nitrogen
witch are exchanged with OH- ions when absorbed and these will raise the pH.
A good ratio will tend to keep pH almost stable.
> 
>    For the tomatoes, it's probably because of a too high pH and the plant dont
>    get all micro nutrient it's need. Also at a ph of around 7.0, nitrogen is
>    less available and that's why you get yellow leaves after a period of time.
> 
>    Normally if lower leaves turn yellow you need more nitrogen, if it's the top
>    leaves it's a micro nutrients deficiency. Could you tel more about your
>    yellow leaves. 
> 
> So far this year my leaves aren't yellow.  They were yellow last year.
> It was, I believe, the lower leaves that turned yellow.  They would
> also become dry and "crunchy" after a while.
> 
> 			Rob
> 

For your leaves it is mainly the nitrogen but also when you are almost ready
to harvest your first tomatoes you must increase the amount of potassium to
get 1.5 time the amount of nitrogen in your solution.

claude

From [email-masked]  Ukn Jul 19 16:18:05 1993
Date: Mon, 19 Jul 93 13:13:18 -0700
From: "Robert S. French" <[email-masked]>
Sender: [email-masked]
To: hydro@hawg
Subject: Yellowing of tomato leaves
Status: RO

Ok, my otherwise healthy tomato plant has started to yellow like it
did last year.  It's a slight yellowing starting at the tips of the
leaves and proceeding inward.  The yellowing is between the veins,
which remain green.  There is also a slight curling of the leaves.My
solution pH is currently 5.4 (I have no idea how it go so acid).

Suggestions?

		Rob

From [email-masked]  Ukn Jul 19 23:11:36 1993
From: [email-masked] (Claude Gelinas Agr.)
Subject: more on yellow tomatoes
To: [email-masked] (culture hydroponique)
Date: Mon, 19 Jul 1993 22:41:13 +0000 (GMT)
Content-Length: 2175      
Status: RO

>From claude Mon Jul 19 22:38:04 1993
Subject: Re: Yellowing of tomato leaves...
To: [email-masked] (Robert S. French)
Date: Mon, 19 Jul 1993 22:38:04 +0000 (GMT)
In-Reply-To: <[email-masked]> from "Robert S. French" at Jul 19, 93 01:13:18 pm
X-Mailer: ELM [version 2.4 PL21]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Length: 1748      

Hi, your ph is too low probably because you use the wrong type of nitrogen.
Your fertiliser solution contains too much of ammonium type nitrogen (NH4+)
and when your tomatoes absorb that type of nitrogen it in fact exchange it
with an H+ that drop your pH solution. Check the label on the fertilizer you
use. it must tell the type of nitrogen and how much of it is in the bag.

ex. the well known 20-20-20 soluble fertiliser have 12 units out of 20 from
urea, 6 units in NO3- and 2 in the NH4+ form and that information is supposed
to be written on the bag or available from your fertilizer dealer.

in hydroponic you must have 80% or more of the nitrogen in the nitrate form
(NO3-) and the remainder in NH4+  and absolutely no urea because it wont be
absorbed by the plant in hydroponic. Urea need to be broken by an enzyme
that is every where in the soil but absent in hydroponic.

So when your pH go down, raise the amount of NO3- in your fertiliser
solution.

The yellowing may be the result of that low ph because at that ph some
micronutrients are not well absorbed by your plant. tel me more about your
yellow leaf. If it's the new one, it's a micronutrient deficiency, probably
iron. By the way, what is the weather since few days at your place, because
real high temperature could induce iron or manganese deficiency that will
last for about two weeks and will turn the head of your plant yellow in just
few hours. If it's the problem spray leaves with iron or manganese sulphate
or chelate to overcome that problem at about 100 ppm solution.

If it's the old leaves the nitrogen is the problem and the low pH is
the thing to check.

I'll check in my note and send you a description of symptoms for each
deficiency in few days.

Claude 

From [email-masked]  Ukn Aug  2 13:06:27 1993
From: [email-masked] (John Schuch)
Subject: hydroponic questions
To: [email-masked]
Date: Mon, 2 Aug 93 9:55:11 MST
Status: RO

Hello? Hello? Does this thing work?

I've been looking through a hydroponic catalog I received last week
and had a couple of questions possibly you could answer.

There are two products in question: The first is a ventilation system
made of thin polyethylene tubing which directs air right to the base
of the plant. The second is a nitrogen system which releases nitrogen
right on the plant. 

Now the question is, given that a greenhouse in Phoenix in the summer
would seem to need the coolers running full-tilt all day to keep the
thing from melting down :-), what good would either of those products
do?

With the tubing ventilation system, what does it do that a ceiling fan
could not?

John

-- 
+--------------------------------------------------------------------------+
| John R. Schuch  -  Motorola Computer Group  -  Manufacturing Engineering |
| N7XVS - [email-masked] - (602)438-3008 - CompuServe: 70733.3330  |
+--------------------------------------------------------------------------+

From [email-masked]  Ukn Aug  2 16:05:19 1993
Date: Mon, 2 Aug 93 13:00:59 -0700
From: "Robert S. French" <[email-masked]>
Sender: [email-masked]
To: [email-masked] (John Schuch)
Cc: [email-masked]
Subject: Re: hydroponic questions
Status: RO

   From: [email-masked] (John Schuch)
   Date: Mon, 2 Aug 93 9:55:11 MST

   Hello? Hello? Does this thing work?

I sure hope so :-)

   With the tubing ventilation system, what does it do that a ceiling fan
   could not?

Well, I'm going to take a random guess at this, which may or may not
be right.  Not all plants like to be submerged in water 24 hours a
day.  That's why many hydro systems fill up the aggregate and then let
it drain back out.  Likewise, that's why it's good to soak your soil
and then let it drain completely.  When you soak a medium, all the
spaces fill with water.  As the water drains, air is drawn down into
the soil.  You then have water clinging to soil/agg particles, with
air in between the particles.  This is the environment many plants
like to grow in.  My guess if this ventilation system is for supplying
roots with air under water.  It has nothing to do with cooling.

I didn't see a question about the nitrogen sprayer you mentioned.

			Rob

From [email-masked]  Ukn Aug  2 16:05:19 1993
Date: Mon, 2 Aug 93 13:00:59 -0700
From: "Robert S. French" <[email-masked]>
Sender: [email-masked]
To: [email-masked] (John Schuch)
Cc: [email-masked]
Subject: Re: hydroponic questions
Status: RO

   From: [email-masked] (John Schuch)
   Date: Mon, 2 Aug 93 9:55:11 MST

   Hello? Hello? Does this thing work?

I sure hope so :-)

   With the tubing ventilation system, what does it do that a ceiling fan
   could not?

Well, I'm going to take a random guess at this, which may or may not
be right.  Not all plants like to be submerged in water 24 hours a
day.  That's why many hydro systems fill up the aggregate and then let
it drain back out.  Likewise, that's why it's good to soak your soil
and then let it drain completely.  When you soak a medium, all the
spaces fill with water.  As the water drains, air is drawn down into
the soil.  You then have water clinging to soil/agg particles, with
air in between the particles.  This is the environment many plants
like to grow in.  My guess if this ventilation system is for supplying
roots with air under water.  It has nothing to do with cooling.

I didn't see a question about the nitrogen sprayer you mentioned.

			Rob

From [email-masked]  Ukn Aug  6 00:07:22 1993
From: [email-masked] (Tim Endres)
To: [email-masked]
Subject: Re: hydroponic questions
Date: Thu, 5 Aug 93 19:55:52 EST
Cc: [email-masked]
Organization: ICE Engineering, Inc.
Reply-To: [email-masked] (Tim Endres)
Status: RO

In Regards to your letter <[email-masked]>:
> There are two products in question: The first is a ventilation system
> made of thin polyethylene tubing which directs air right to the base
> of the plant. The second is a nitrogen system which releases nitrogen
> right on the plant. 

We have used many "atmosphere enhancement" mechanisms. The reality
of it, though, is that the atmosphere is the absolute last thing
that you really wish to worry about optimizing.

> Now the question is, given that a greenhouse in Phoenix in the summer
> would seem to need the coolers running full-tilt all day to keep the
> thing from melting down :-), what good would either of those products
> do?
> 
> With the tubing ventilation system, what does it do that a ceiling fan
> could not?

Nothing can do more for your plants than *strong* (I mean high capacity)
ventilation. Ventilation is more critical than many other things.
Thus, invest in an exhaust system that can exhaust a *lot* of air
in a short time. Combined with a reasonable source of cool air to
replace that which is exhausted, you will get about the best air
temperature control that you can want. One way to get good cool air
is to pull it from underground. Some people have run a heat duct
down through a deep ditch that they dug and buried. Others have run
it through cool water. In Pheonix, you may not have many options.

Also, under hot conditions, you need to be very concerned about the
temperature of the nutrient solution. Too hot, and the plants will
not be able to exchange nutrients well at the roots. Thus, I would
set up some system that allows you to have some control over the
nutrient solution's temperature. Even ice cubes added occasionally
can give you pretty good control.

tim endres - [email-masked]  (UUCP: heifetz!tbomb!time)

USENET - a slow moving self parody... ph

From [email-masked]  Ukn Aug  6 00:08:53 1993
From: [email-masked] (Tim Endres)
To: [email-masked]
Subject: Re: hydroponic questions
Date: Thu, 5 Aug 93 20:00:51 EST
Organization: ICE Engineering, Inc.
Reply-To: [email-masked] (Tim Endres)
Status: RO

In Regards to your letter <[email-masked]>:
> Well, I'm going to take a random guess at this, which may or may not
> be right.  Not all plants like to be submerged in water 24 hours a
> day.  That's why many hydro systems fill up the aggregate and then let
> it drain back out.  Likewise, that's why it's good to soak your soil
> and then let it drain completely.  When you soak a medium, all the
> spaces fill with water.  As the water drains, air is drawn down into
> the soil.  You then have water clinging to soil/agg particles, with
> air in between the particles.  This is the environment many plants
> like to grow in.  My guess if this ventilation system is for supplying
> roots with air under water.  It has nothing to do with cooling.

This is another reason why the Thin Film Nutrient system is so
good in my opinion. The nature of the "mat", which is continually
"pulling" solution down past the roots, gives excellent and 
natural aeration while the solution is flowing. Plus, since the
solution is rarely more than 1/8" deep, and the roots exist
in a large open area, there is a great deal of exposure to air
for the roots.

tim endres - [email-masked]  (UUCP: heifetz!tbomb!time)

USENET - a slow moving self parody... ph

From [email-masked]  Ukn Aug  6 08:48:58 1993
From: [email-masked] (John Schuch)
Subject: Thin Film Nutrient System?
To: [email-masked]
Date: Fri, 6 Aug 93 5:39:14 MST
Cc: [email-masked]
Status: RO

> 
> This is another reason why the Thin Film Nutrient system is so
> good in my opinion. The nature of the "mat", which is continually
> "pulling" solution down past the roots, gives excellent and 
> natural aeration while the solution is flowing. Plus, since the
> solution is rarely more than 1/8" deep, and the roots exist
> in a large open area, there is a great deal of exposure to air
> for the roots.
> 
> tim endres - [email-masked]  (UUCP: heifetz!tbomb!time)
> 

Could you give me a simple explanation of how the Thin Film
system works? It's not in the books I have.

Tnx,
John

-- 
+--------------------------------------------------------------------------+
| John R. Schuch  -  Motorola Computer Group  -  Manufacturing Engineering |
| N7XVS - [email-masked] - (602)438-3008 - CompuServe: 70733.3330  |
+--------------------------------------------------------------------------+

From [email-masked]  Ukn Aug  6 08:59:55 1993
From: [email-masked] (John Schuch)
Subject: solution temperature
To: [email-masked]
Date: Fri, 6 Aug 93 5:47:58 MST
Cc: [email-masked]
Status: RO

> Nothing can do more for your plants than *strong* (I mean high capacity)
> ventilation. Ventilation is more critical than many other things.
> ......
> down through a deep ditch that they dug and buried. Others have run
> it through cool water. In Phoenix, you may not have many options.

I plan on placing evaporative cooling pads at one end and fairly large
exhaust blowers at the other. That's about the best that can be done
here short of refrigeration.

> 
> Also, under hot conditions, you need to be very concerned about the
> temperature of the nutrient solution. Too hot, and the plants will
> not be able to exchange nutrients well at the roots. 

I had not considered that. How hot is "too hot?"

>
> Thus, I would
> set up some system that allows you to have some control over the
> nutrient solution's temperature. Even ice cubes added occasionally
> can give you pretty good control.
> 

I imagine I could use the cold water reservoir from the evaporative
cooling system to control the solution temperature. I'll have to
think about that.

tnx
John

-- 
+--------------------------------------------------------------------------+
| John R. Schuch  -  Motorola Computer Group  -  Manufacturing Engineering |
| N7XVS - [email-masked] - (602)438-3008 - CompuServe: 70733.3330  |
+--------------------------------------------------------------------------+

From [email-masked]  Ukn Aug  6 13:22:18 1993
From: [email-masked] (Tim Endres)
To: [email-masked]
Subject: Re: Thin Film Nutrient System?
Date: Fri, 6 Aug 93 12:48:37 EST
Cc: [email-masked]
Organization: ICE Engineering, Inc.
Reply-To: [email-masked] (Tim Endres)
Status: RO

In Regards to your letter <[email-masked]>:
> Could you give me a simple explanation of how the Thin Film
> system works? It's not in the books I have.

Thin film is pretty simple.

Nutrient is "pulled" over the roots via capillary and gravity action
in a very thin film (about 1/8 inch). The nutrient flows continually.

The home brew system that I have seen consists of 4 inch pvc tubes.
Then concrete was poored down them to create a flat surface about
a third of diameter. The flat surface is critical, since most of the
nutrient "spreads out" via capillary action. Then they placed a "mat"
that they purchased at the nearest fabric store down on top of the
concrete flat part. Then the tubes are set at an incline of about
one inch per 5 feet. Nutrient is pumped from the resevoir to the
"top" of the tubes and allowed to "trickle" down the matting across
the roots of the plants and back into the resevoir. The trickle rate
is precisely one quart per minute. The capillary action of the matting
pulls the nutrient out so that you don't get a tiny stream that only
covers a small part of the roots. Thus, there is about a 2.5" area
of dark air around the roots. The plants grow up out of 2 inch holes
cut into the PVC tubing and are started in rockwool and placed into
the tubes when they are big enough. The rockwool is the one inch cubes
so they fit and the small holes help support the stem.

The system I use is commercial, from SunCore Systems (1 503 281 6401
ask for Chuck). It is plastic triangular tubes with flat bottoms (this
avoids the problem of flattening round pvc tubing). It has a mat
that is about 6 inches wide, which helps a lot and has more capacity
than the 4 inch pvc, which only provides about a 2.5 inch flat mat.
The nutrient is pumped up the tubes via a small (3/4 inch) pvc tube
running up inside the larger triangular tube. I love this system and
it has produced results that I have never seen with any other hydro
system.

Finally, with Thin Film IT IS VERY CRITICAL to have the correct nutrient.
SunCore provides the best I have used, and I have had other supposedly
hyodro nutrients "burn" my plants. The problem stems from UREA based
nitrogen used in most, since there are no micro organisms in the tubes
as in soil to break down the urea. Otherwise the urea will burn the
roots and ultimately kill the plants, or severely restrict their growth.

tim endres - [email-masked]  (UUCP: heifetz!tbomb!time)

USENET - a slow moving self parody... ph

From [email-masked]  Ukn Aug  6 13:24:35 1993
From: [email-masked] (Tim Endres)
To: [email-masked]
Subject: Re: solution temperature
Date: Fri, 6 Aug 93 12:52:26 EST
Cc: [email-masked]
Organization: ICE Engineering, Inc.
Reply-To: [email-masked] (Tim Endres)
Status: RO

In Regards to your letter <[email-masked]>:
> > Also, under hot conditions, you need to be very concerned about the
> > temperature of the nutrient solution. Too hot, and the plants will
> > not be able to exchange nutrients well at the roots. 
> 
> I had not considered that. How hot is "too hot?"

If you look hard enough, you will find a couple tables that show the
nutrient exhanges "zones" of plants for both temperature and pH.
I can't point you to one, since I copied mine long ago, and have
had little need to look at it in years.

However, general rule of thumb is that the nutrient has to have the
proper pH and have a temperature in the 62-68 degree range. I do 
believe that pH is a little more important than temperature, but
temp is the easier to control and monitor.

A "dissovled salts" meter is also vital to keep the nutrient concentration
in a good region.

tim endres - [email-masked]  (UUCP: heifetz!tbomb!time)

USENET - a slow moving self parody... ph

From [email-masked]  Ukn Aug 19 16:30:56 1993
Date: Thu, 19 Aug 93 13:26:22 -0700
From: "Robert S. French" <[email-masked]>
Sender: [email-masked]
To: hydro@hawg
Subject: More on the tomato saga
Status: RO

Well, my tomatoes are getting a lot worse now.  The lower leaves turn
yellow first, with the yellow appearing between the veins, while the
veins stay green.  My thanks for all the suggestions - I imagine
MirAcid has far too much urea in it.

I just received a large order from Hydrofarm.  Among other things I
got a dissolved solids tester and 12 pounds of crystalline nutrient (no
urea).  I'll try replacing the solution with this new nutrient, and
watch the pH carefully to see if it helps.

How does one use a dissolved solids tester?  Do I make up some
solution, measure it, and then see when it drops too much?  Or is
there some recommended level so that I should add nutrient until the
level is reached?

		Rob

From [email-masked]  Ukn Aug 23 15:32:11 1993
From: [email-masked] (John Schuch)
Subject: Opaque vs. Clear Storage Tanks
To: [email-masked]
Date: Mon, 23 Aug 93 12:21:43 MST
Status: RO

One of the books I've read mentions that the nutrient solution storage
tanks should be opaque. I have found some plastic tanks that would be
ideal for the space I have and are very inexpensive. They are, however,
white and translucent.

Does the solution REALLY need to be kept in the dark?

John

-- 
+--------------------------------------------------------------------------+
| John R. Schuch  -  Motorola Computer Group  -  Manufacturing Engineering |
| N7XVS - [email-masked] - (602)438-3008 - CompuServe: 70733.3330  |
+--------------------------------------------------------------------------+

From [email-masked]  Ukn Aug 24 11:32:52 1993
From: [email-masked] (Tim Endres)
To: [email-masked]
Subject: Re: Opaque vs. Clear Storage Tanks
Date: Tue, 24 Aug 93 10:43:57 EST
Cc: [email-masked]
Organization: ICE Engineering, Inc.
Reply-To: [email-masked] (Tim Endres)
Status: RO

In Regards to your letter <[email-masked]>:
> 
> One of the books I've read mentions that the nutrient solution storage
> tanks should be opaque. I have found some plastic tanks that would be
> ideal for the space I have and are very inexpensive. They are, however,
> white and translucent.
> 
> Does the solution REALLY need to be kept in the dark?
> 
> John
> 
> -- 
> +--------------------------------------------------------------------------+
> | John R. Schuch  -  Motorola Computer Group  -  Manufacturing Engineering |
> | N7XVS - [email-masked] - (602)438-3008 - CompuServe: 70733.3330  |
> +--------------------------------------------------------------------------+

The problem is algea growth in the tanks. The opaque tanks prevent
the growth. If you can cover or keep in a dark place to prevent the
algea you should be able to use them

tim endres - [email-masked]  (UUCP: heifetz!tbomb!time)

USENET - a slow moving self parody... ph