Fertilizer ppm question
Login
User Name
Password   


Registration is FREE. Click to become a member of OrchidBoard community
(You're NOT logged in)

menu menu

Sponsor
Donate Now
and become
Forum Supporter.

Fertilizer ppm question
Many perks!
<...more...>


Sponsor
 

Google


Fauna Top Sites
LOG IN/REGISTER TO CLOSE THIS ADVERTISEMENT
  #11  
Old 08-17-2017, 09:30 AM
Ray's Avatar
Ray Ray is offline
Senior Member
 

Join Date: May 2005
Member of:AOS
Location: Oak Island NC
Posts: 13,111
Fertilizer ppm question Male
Default

While the molecular "packing" can play a role, I think that the manufacturing processes and the resultant particle shapes is far more important, as it greatly affects the bulk density of a powder.

I know from measuring it that different lots of the same formula of MSU fertilizers can vary in bulk density by as much as 20%, depending upon the source of the raw materials. That's why I always weigh it out and make a concentrated solution, because in that case, a fixed volume will always provide the same nutrient loading.
__________________
Ray Barkalow, Orchid Iconoclast
FIRSTRAYS.COM
Reply With Quote
  #12  
Old 08-18-2017, 08:25 PM
terryros terryros is offline
Senior Member
 

Join Date: Feb 2008
Zone: 4a
Location: Minneapolis, MN
Posts: 266
Fertilizer ppm question Male
Default

PPM is the common way that the N concentration in a fertilizer solution is indicated, as noted by other replies. However, almost quoting Bill Argo from his important series on pH and nutrients, TDS is a poor way to reflect all of the salts in a fertilizer solution. Electrical conductivity (EC) is what is being measured anyway and then TDS is estimated with a single conversion factor, even though different salts need different conversion factors.

In the same series of articles, Bill Argo places orchids in the "low fertility" category and notes that the likely acceptable EC range is 1000-2500. Most TDS-only meters would probably measure this as about 500-1250 TDS.

Even at 100 ppm N concentration, different fertilizers give quite different EC values because of the differences in the concentrations in other salts. My K-Lite solution at 83 ppm N this morning measured about 700 EC (probably would measure about half this number with a TDS meter). Only a grower who fertigated about every day with a very weak fertilizer solution would be able to get a total EC value to be very low. I don't think there is evidence that total EC of a fertigation solution around 1000 would have any adverse effects. However, this points out that if you start with a water source that already has a high EC and then add substantial fertilizer to it, you can end up with a total EC that could be in the worry zone.
Reply With Quote
  #13  
Old 09-30-2017, 12:41 AM
D_novice D_novice is offline
Senior Member
 

Join Date: Oct 2015
Zone: 9b
Location: Marin County, CA
Posts: 241
Fertilizer ppm question Male
Default

Quote:
Originally Posted by estación seca View Post
Paphiopedilum 50 ppm and under preferred. (Advice from Fred Clarke at SVO.)
While I'm not going to question Fred Clarke's Paph acumen, the Huntington Museum has one of the world's greatest Paph collections, and their water is 200-800 PPM, per an article in one of the journals (maybe the CSA).

I ask for lots of opinions in order to learn as much as possible - including on this forum - but as in life, I've noticed that basically no one knows anything for sure.
Reply With Quote
Post Thanks / Like - 1 Likes
Likes My Green Pets liked this post
  #14  
Old 09-30-2017, 01:13 AM
estación seca's Avatar
estación seca estación seca is offline
Senior Member
Fertilizer ppm question
 

Join Date: Jun 2015
Zone: 9b
Location: Phoenix AZ - Lower Sonoran Desert
Posts: 13,874
Fertilizer ppm question Male
Default

Quote:
Originally Posted by Ray View Post
Per the manufacturer, 1.45g/gal will yield a 50 ppm N solution.

Translating mass to powder volume (especially heterogeneous ones like the Greencare MSU formulas) is damned difficult and inaccurate.

That said, dividing 4 by the %N on the label is a way to estimate the teaspoons/gal for 50 ppm N, so 1/8 tsp/gal of a 13%N formula is more like 15 ppm N.

Personally, I think the discussion of what TDS a plant can tolerate is of no value. These guys have evolved to expect very little food, provided in many, small doses, so it makes sense that mimicking that is the better approach.

Humans can "tolerate" a booze binge, but doing that periodically will be ultimately harmful, while a small amount, consumed regularly, has been shown to have health benefits.
Fred meant 50 ppm total dissolved solids, not just N. He made this clear in the discussion.

I reported elsewhere here on Orchid Board Brandon Tam's lecture to our orchid society about how the Huntington grows Paphs.

---------- Post added at 09:13 PM ---------- Previous post was at 08:57 PM ----------

As Naoki pointed out, some nutrients are actively taken up by roots. That means the plant expends energy absorbing these nutrients. Water tends to flow passively, replacing that transpired when stomata are open.

Some nutrients - calcium is an example - are excluded from most plant roots, except at the narrow collar near the root tip. I don't know whether this calcium exclusion is found in orchid roots. Without this plants would be flooded with calcium, a common mineral in most ground water. This mineral plays a part in regulating enzymatic activity inside plants, just as in animals, so too much calcium would be fatal.

Root "burn" is often an osmotic issue. In other words, it is mainly related to the number of dissolved osmotically active particles in the solution - if the external water solution has a higher particle concentration than the plant, water flows out of the plant through the roots, or the plant is unable to take up water. This leads to root death.

Nutrition is different from water balance. What growers are interested in is providing sufficient nutrients to plants without causing an osmotic problem at the roots, or preventing adequate water uptake. Orchids don't need much nutrition, but they do need a lot of water.

Electrical conductivity measures the number of particles carrying an electrical charge in the solution. It can't be translated to TDS without knowing exactly what chemical species are in the solution, and in what amounts.

EC can be used to compare relative proportions of the exact same mineral mixture added to water, so it can be used to measure fractions or multiples of a known constant concentration of a particular fertilizer product of unvarying composition, when mixed in different volumes of water. EC can't provide much useful information for a solution of unknown composition.

It is possible to have a solution with very low EC that has so many osmotically active particles roots would be killed - an example would be a concentrated solution of table sugar.

During periods of high humidity, most fertilizer powders absorb water from the atmosphere, without much changing the volume in the container. That quarter-teaspoon will weigh more during humid times than in arid times.

Fortunately for us orchids don't need much fertilizer.
__________________
May the bridges I've burned light my way.

Weather forecast for my neighborhood

Last edited by estación seca; 09-30-2017 at 01:17 AM..
Reply With Quote
  #15  
Old 10-01-2021, 07:23 PM
Shadeflower's Avatar
Shadeflower Shadeflower is offline
Senior Member
 

Join Date: Apr 2021
Posts: 923
Fertilizer ppm question
Default

Quote:
Originally Posted by rbarata View Post
I got some advise from fellow board members to water with a 150 ppm solution.

My NPK is 13-3-15 and the recommend concentration is 1/2 gr per 5 liters (1 teaspoon/0,75 gallon).

Result:
ppm TDS (N+P+K only)=265
ppm N=129

So I assume these recommendations are referenced to N only.
Sorry for dragging up a 4 year old post. I have just done the calculations for my own fertilizer as I detailed in a different thread and came across this one to compare my numbers.

So it seems my math is all correct. This can be verified via Ray's ppm calculator:

Fertilizer PPM Calculator › First Rays LLC

So everything posted in this thread matches my numbers so far except this statement ^^

At 265ppm TDS there is no way that the N content (being 13%) will come out at 129 ppm N...

I don't even know what values to add into the calculator.

Rbarata, I know you still frequent this site and I know this was a long time ago in which time you will have a better understanding so maybe we can rectify these wrong numbers.

you say you added 0.5grams per 5 liters but then also say this works out as 4.2grams(1 teaspoon) per 0.75 gallons.
If I convert that it works out as 4.2grams per 2.85 liters or 1.5 grams per liter.

so which number do I put into Ray's calculator?
0.1 grams per liter or 1.5 grams per liter?

The one gives an N value of 16 ppm
The other gives a value of 234 ppm N

Quite a bit of discrepancy from the 129 ppm N which like said was impossible also as 13% of 265 ppm should be much lower, I'd estimate 30-50 ppm N (according to the calcuator at 1g/gallon it would be 33 ppm N)

Not surprised people get confused by these calculations

Anyway, I know this is 4 years old so old news but new members like to know how much to feed.

I think the feeding chart by ES is pretty good apart from the Vanda feeding rates (based on me having caused root burn using over 500ppm but that is a matter of opinion)

Last edited by Shadeflower; 10-01-2021 at 07:32 PM..
Reply With Quote
  #16  
Old 10-15-2021, 08:07 PM
SADE2020's Avatar
SADE2020 SADE2020 is online now
Senior Member
Fertilizer ppm question
 

Join Date: Dec 2020
Location: Palma de Mallorca
Posts: 750
Fertilizer ppm question Female
Default

I just got a gift from a friend that works with Biobizz in Spain. The Grow numbers are 4-3-6 the flower or bloom one is 2-7-4. I've never, ever ...used any fertilizer below 18N...However, I use like 1/3 of the measurement. This product indicates 1ml x 1L.

Is this up for orchids or is a weed fertilizer... ?



Review No.2
Ok, another gift is this product ..again, I don't get if ia appropriate for orchids at all. This one is 2.5%N - 5%P - 7%


__________________
Sade
***Mediterranean Conditions; learning something new every day ***
________________________________________
If you want to check 🔍 my stuff:
www.sadeorchids.com
Instagram

🌿🌸
Reply With Quote
  #17  
Old 10-15-2021, 11:55 PM
Ray's Avatar
Ray Ray is offline
Senior Member
 

Join Date: May 2005
Member of:AOS
Location: Oak Island NC
Posts: 13,111
Fertilizer ppm question Male
Default

Such products are designed to make money, not to be by better for plants.

They add nothing, but probably are not harmful.
__________________
Ray Barkalow, Orchid Iconoclast
FIRSTRAYS.COM
Reply With Quote
Post Thanks / Like - 1 Likes
Likes SADE2020 liked this post
  #18  
Old 10-16-2021, 08:23 AM
SADE2020's Avatar
SADE2020 SADE2020 is online now
Senior Member
Fertilizer ppm question
 

Join Date: Dec 2020
Location: Palma de Mallorca
Posts: 750
Fertilizer ppm question Female
Default

😁
Quote:
Originally Posted by Ray View Post
Such products are designed to make money, not to be by better for plants.

They add nothing, but probably are not harmful.
Thank you Ray.
I'll use it with other plants then.
__________________
Sade
***Mediterranean Conditions; learning something new every day ***
________________________________________
If you want to check 🔍 my stuff:
www.sadeorchids.com
Instagram

🌿🌸
Reply With Quote
Reply

Bookmarks

Tags
150ppm, concentration, fert, npk, ppm


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
MSU fertilizer, silly question (really) dbarron Beginner Discussion 12 04-27-2016 06:09 AM
Amazing New Fertilizer ronaldhanko Scientific Matters 120 06-12-2015 02:20 PM
A question about fertilizer Kailyn Beginner Discussion 2 01-04-2014 01:58 PM
Question about fertilizer butterfly_muse Beginner Discussion 18 08-04-2013 04:11 PM
fertilizer question VickiC Beginner Discussion 4 01-04-2010 11:48 AM

All times are GMT -4. The time now is 05:45 AM.

© 2007 OrchidBoard.com
Search Engine Optimisation provided by DragonByte SEO v2.0.37 (Lite) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Feedback Buttons provided by Advanced Post Thanks / Like (Lite) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.

Clubs vBulletin Plugins by Drive Thru Online, Inc.