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Is EC that big-a-deal on soil growing? I've googled plenty of info about it, electrical conductivity, minerals/salts, bla bla bla, but what do you do about it? Is there some all mighty chart somewhere that gives the meaning of life? What if I just skip it but do the PH thing? How do I search this site when search says "EC is too short and was ommited from the search". Well that's not so good.
Thank you all my green blooded freinds,
Oc. :weedpoke:
EC is a big deal. In some ways its a bigger deal than ph. Salt contect can play havoc with your root developement. And the dirty little secret that a lot of the nute companies don't tell you is that some brands are heavily loaded with salts.
Ooh! Thank you. So with that, is it accpetable to buy a $20 EC meter or must I get a $120 one? Yes you "get what you pay for", although a Honda civic would get me to work as well as a Mercedes Benz. Well, maybe not as well, but it would still get me where I'm going. You dig?Quote:
Originally Posted by killerweed420
This is the city water I'm planning to use (after 1-2 day evaporation) although I think the "keepers of knowledge" and "The widom givers" will tell me to go to the RO water store, yes?
Total Hardness (Range)
Grains
9-19
per Gallon
Parts per Million
(ppm)
152-319
Thanks all,
Oc. P.s. I like the icons that move:
:yippee:
From what I've been researching is that EC shows not only how much salt has built up, that's almost secondary.... It really shows how much fertilizer remains after the plants have used what they need. It seems to be more a measure of exact measures of ferts than salts and minerals from the water.
Correct me if I'm wrong as I'm trying to anser my own question.
Cheers Blokes.
:admin1:
Keep reading.
For out purposes, "ferts" are "salts"...
Quote:
Originally Posted by DreadedHermie
So what you are saying is if you give a person a fish they eat for a day. If you teach a man to fish they eat for a life time...
:postreadfaq:
...... Salts are ferts...... Yes, of course...... Yes....... Back to the books for me!
:detective1:
got link?
:)...Text
Yes, I read that and frankly, it's part of the problem. It's great for impressive big "science book" words. It actually says nothing about what EC should be or what to do about it, does it?Quote:
Originally Posted by Dutch Pimp
I found some other info that speaks in normal every day language. It's like it was meant to be understood by some one who does not already know it all. It explains what EC should be, how it should react, and what one should actually DO about it! :
Grow Marijuana FAQ, Cannabis cultivation - marijuana growing tips & photos
TDS, PPM, and EC
If you have any desire to mix your own fertilizers, it is important that you have at least basic understanding of these terms
Electricity is conducted due to the presence of ions (electrically charged) in a solution. The ions get there by introduction of salts via our ferts!
EC (electric conductivity) is a representation of how much potential a solution has to conduct electricity...SO, by testing the ability of a solution to conduct electricity, we can indirectly determine the amount of salts present....thereby knowing if we have the right concentration of ferts.
E.C. is a measure of salinity by measuring its conductivity. You want an E.C. under 2.0.....anything around 4.0 signifies an extreme excess of salt which calls for immediate leeching. There are devices for measuring...honestly, I haven't bought one because I am pretty comfortable with this....but if you experiment may be worth a look!
Despite my natural aversion for ppm measurement, it would be a good idea when mixing ferts as a beginner. Check your nursery or Home Depot. I've F-ed up a plant or two in my day, always because I THOUGHT I was more accurate with eye measurement than I really was!
CF (Conductivity Factor) basically represents the same information but expressed differently. 1 ms/cm is equal to a CF of 10. I don't use this factor and haven't seen many people use it...but just in case, you now have a conversion!
TDS is a measurement, by weight, of the Total Dissolved Solids in a solution and is measured in PPMs (Parts Per Million). Basically, when you hear someone say they introduce nutrients at a rate of 500 PPMs, it means that they have 500 milligrams of solid dissolved in a Liter of water.
You can figure the PPM of your ferts one of two ways.....you can precisely measure the ferts and water you mix together...or you can make a solution and measure the PPM of IT. The shortcut lies in hand-held meters which measure the EC of a solution and then apply mathematical conversion to the EC figure to arrive at PPMs. Keep in mind, even this is an approximate measurement...but plenty accurate for growers!
Some meters actually display the EC AND the PPM readings. Some only express the EC value and this can be tricky because European and American made meters measure at different rates.
An American device that displays an E.C. of 1.0 has 500PPMs.
A European device that displays an E.C. of 1.0 has 640PPMs.
(I believe Australian manufacturers have a different conversion factor also...but not sure.)
So if your American device only displays E.C., use that old algebra and set the two given equations equal to each other. For example, let's say your E.C. reading is 1.2.
Using the known ratio given just above, we'll cross multiply to solve for x to get the unknown ppms.
1.0/500ppm=1.2/x
x=600
Your solution has 600PPMs. (remember, this would be with the American device...a European device would produce a different result!)
If you want to figure out the PPMs yourself, its pretty easy. Each 1 gram of fertilizer per liter of water gives 10PPMs of each given nutrient per percentage point. Sounds clumsy, wish I could state that better....here's an example.
Use 1 gram of SuperPhosphate 0-20-0 in a liter of DISTILLED water. The solution would have 0ppm of N, 200ppm of P, and 0ppm of K. Also keep in mind that tap water already has dissolved solids...most likely anywhere between 200-400 PPMs. Use distilled water when possible...0 PPMs!!
A guideline for NPK strengths
Now, I have seen different parameters for acceptable PPMs. Here is a decent guideline for the N-P-K standards...play around, but make only gradual changes up! Approximate tolerance range of PPMs per nutrient .... most micronutes are tolerated by plants within the same ranges...but the plant just doesn't need nearly that much!
N 200-400
P 200-600
K 200-600
Approximate tolerance range of TOTAL PPMs in soil/medium
(Obviously the plant can tolerate more as it gets larger and has more root area to uptake nutes and leaf area to transpire water.)
Seedling 500-600
Vegetative 800-1000
Flowering 1000-1500
Flushing 500
PPMs for each growth phase
You may desire more N during veg stages for example. The key is NOT to obsess over the exact numbers. Too many experienced growers give advice in exact parameters to appear 'scientific' or something...but there are too many other factors involved in the actual UPTAKE of these nutrients by roots to claim specificity. These are just general parameters that you can tweak under your own conditions. And again, the plant can tolerate more as it gets larger and has more root area to uptake nutes and leaf area to transpire water...start light, gradually increase with each feeding as your lant can handle it.
Keep in mind, my estimates are given for soil mediums which can tolerate higher levels because the soil components will bond with many elemental ions....a hydro system needs to be more precise....I'm not very familiar with those systems. You've read the dislaimer! Also remember that these parameters are based on the assumption of using DISTILLED water. Tap water will add another 200-400 PPMs, so you would have to adjust accordingly...especially with Cl, Ca, Na, and in rare case, S.
SEEDLING (2-3 weeks...look for 4-5 sets of alternating nodes before moving to veg)
N 150
P 100
K 150
Ca 75
Mg 75
S 25-50
Fe 15
Cl 15
Mn 7
Cu 9
Zn 3
Total: 600ppm
VEGETATIVE/PRE-FLOWER (2-4 weeks)
N 300
P 100
K 200
Ca 100
Mg 100
S 50-75
Fe 25
Cl 25
Mn 10
Cu 15
Zn 5
Total: @1000pm
FLOWER (strain dependent-usually 6-8 weeks)
N 300-400
P 400
K 200
Ca 100-150
Mg 100-150
S 100-150
Fe 25+
Cl 25+
Mn 10
Cu 15
Zn 5
Total: @1300-1500ppm
FLUSH/HARVEST (2 weeks)
N 0
P 75
K 75
Ca 50
Mg 50
S 50
Fe 25
Cl 25
Mn 10
Cu 15
Zn 5
Total: @400ppm
I cannot stress enough that these are estimates...conservative ones due to the fact that chemical ferts allow less room for error. In addition, different strains and conditions will result in different ratios....experiment often and use caution always!
And................
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The nutrient assimilation rate is further enhanced by the reduction in solution TDS/EC, which reduces osmotic pressure and allows the roots to draw the nutrients "easier". Young, established seedlings or rooted cuttings are started at 500-600ppm. The TDS is increased to 800-900ppm during peak vegetative growth. During the transition from early to heavy flowering, TDS is further raised to 1000-1100ppm. It is then reduced to 400-500ppm during the final 2 weeks of flushing. The plants demonstrate their preference for a lower TDS/EC when running a lower pH by clearly sustaining higher growth rates.
This is informative although it's for hydro:
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It's simple to find out if you are using too much food or not enough by watching the nutrient concentration levels in your tanks day to day. Don't be concerned with the exact reading, rather watch how it rises and falls from each day to the next. The differences between when you put the solution into the tank and the readings you get several hours later or the next day are what tell you if your plant is eating, drinking or happy.
Start with 1.00 EC (or a SAFE nutrient strength). Next day, if it reads 1.4, it means your plants have been using water and your nutrient solution is becoming more concentrated. This means the concentration of nutrients is too high, so you dilute.
If the meter reads lower than the previous day, 0.7 say, it tells you that the plants are eating nutrients faster than they are drinking water, so you should increase your nutrient strength. If it remains the same, your feeding schedule is on target for now. The nutrient/water intake fluctuates with the growth of the plant, so you must continually monitor it day to day.
Your plants will tell you the optimum nutrient levels. When they are receiving optimum food and water, the readings remain constant. The more you do it, the easier it gets. The reason no one can tell you what PPM/EC levels to use is because every garden is different and every plant has different requirements due to their particular environment. That's why you have a ball park starting figure, but after that your plants will tell you almost exactly what they require.
I just got a fancy expensive EC meter. It's a rapitest 4 in 1 tester which checks PH, Fertility (salts is you want to sound techy and confusing), Moisture and even light level. According to my PH test drops and after flushing the meter is saying exactly what it "seems" like it should be.
Meter on Epay:
GARDEN SOIL PLANT TESTER pH NPK LIGHT MOISTURE 4 in 1 - eBay (item 150405186937 end time Feb-12-10 13:22:25 PST)
I've been doing Dr. Mengela experiments on a few test subject plants and sure enough the "fert +" subject is reading high fertility and high PH and my "fert -" is reading low ferts and normal PH. The meter obviously works!
So be known, the purists will call you a second class citizen for using the $15 4 in 1 three probe meter so I say let 'em. I 'aint payin' no $250 meter that this meter and the plants can tell me almost as well. This along with what your plants are telling you is all you need. Don't believe the hype.
Oc.
P.s. I'm going to have some pic of plants the group will need to identity so I'll post pix as soon as I'm considered worthy by the powers that be....
:Tomcat:
:admin1: