Can someone awnser questions about EC TDS and watering


#1

Hi everyone
I have been following the blogs and threads on this site since summer, and most of my questions have been answered in previous post. I have not found a answer for one question about runoff water. Let me back up a little and show you guys and girls what I have been up to since Sept 27.

Sept. 27 - Oct 1 Started a WW ILGM fem seed on the 27th also received a BS clone my son in law was not sure he lost track of his clones but he thinks this is a Strawberry Cough or possibly a Pink Lemonade.
If anyone can tell me what the clone is I would kiss you butt on Main St. and give you a hour to draw a crowd.
Anyway my grow in pictures.

Little Lisa on Oct. 4

Orphan Anne ( Because I don’t know who her parents are) She was a gift with no papers.


So as you can see Lisa had a lot of growing to do to catch up to Anne.

Forward to this morning. Sorry about the pictures this is a cheap camera and with the money I have spent on this grow my wife is at the end of her patients,
The girls side by side.

Then the girls in there home.

So here we go, oh ya a support ticket.

Strain; Type, Bag seed, or NA ILGM W.W. Fem and a BS Clone
Soil in pots, Hydroponic, or Coco? Pennington Professional Potting mix 0.01 -0.05-0.12
System type? Soil in 5 gallon buckets in a 24 Grow tent
PH of runoff or solution in reservoir? 6.35
What is strength of nutrient mix? EC, or TDS I try to obtain a EC of 1100 - 1200 with TDS under 700
Indoor or Outdoor indoor 2
4 tent
Light system, size? one 1000 watt full spectrum LED and one 350 full spectrum LED
Temps; Day, Night 77-79 / 65-68
Humidity; Day, Night 65 with humidifier during day 43 without humidifier night time 50 about
Ventilation system; Yes, No, Size using 3 fans
AC, Humidifier, De-humidifier, humidifier
Co2; Yes, No NO

Question # 1
Will Lisa ever catch Anne I use the 1000 watt light on Lisa and the 350 on Anne trying to stunt her a little I also try to stretch Lisa a little.
Is this the right thing to try or ?
Question # 2
When do you think they should be ready for Flower I’m thinking between Christmas and New year.
Question # 3
I just got the TDS/EC meter last week and was wondering if I water with a PH of 6.15 a TDS of 765 and a EC of 1540 what should the runoff be mine was PH 6.12 a TDS of 1090 and a EC of 1280 using 2.5 gallons of water.
After I put her in her home I went to clean her home and had a small amount of water on the floor so I tested it and was surprised to find that the PH was at 5.95 The TDS was 1570 and the EC was at 3120. Is this salts the soil is releasing? Is that normal? Should I flush?
Anyway those results were from Nov. 28 I water Anne this morning and here are the input and out put of watering using plain well water and just adjusting the PH.

Feed PH 6.35 TDS 172 EC 340
Runoff PH 6.35 TDS 474 EC 958
Does this seem right?

Well Thank for the input and thanks for being a great site forum and friends.

Tony


#2

Welcome to the forum Tony.

EC and TDS are different ways of expressing a value taken to measure total dissolved solids. TDS is normally given out in PPM or parts per million. EC stands for electrical conductivity and is given in a British and Canadian format based on a NaCl solution.

You are measuring tds with an output in ppm.

When taking a runoff tds you take the final bit of runoff to sample. In soil it will read higher when the soil is not exhausted or has a buildup of salts. Your values look good.

I would ph between 6.0 and 6.5 and not worry too much.

One thing: be careful not to over water.


#3

Yes I understand TDS my question is more about what it does in the soil should the soil absorb some of the solids (nutes) and in doing so have a lower TDS when leaving soil or should the new water clean the salts out of soil thus giving a higher TDS in the runoff or should you get the same in as out.
Also because I’m a new grower I bought a meter for soil and I water then let drop under the good scale (just slightly) and I water again using 2.5 gallons per plant takes about 3 to 4 days and I cal/mag every feeding and nute up to a TDS reading of 800/PPM
every other feeding.


#4

Your tds will change over time and depending on the age and size of your plant and the pot size. In your case you are adding very low numbers so I would expect the runoff to be higher. A value lower than the input indicates a need for nutrients. A very high number (3,000 ppm) would indicate time to flush.

It’s all a running target.


#5

Yes finding that out but I read almost every post on the forums so I’m learning every day. I now have enough knowledge to really screw thing up. :grin:


#6

You and me both! Hahaha.


#7

Well @Myfriendis410 seems like you were the only person who tried to answer my question but here is the answer i found at this site

Under normal conditions, the EC in the growing media and runoff should be just a little higher than the nutrient solution in the reservoir. If the EC of the solution drawn from the growing medium is higher than the one from the reservoir, there might be starting a fertilizer salt build-up.
An indicative EC range for cannabis plants is 0.8-1.3 for seedlings; 0.5-1.3 for clones; 1.3-1.7 under vegetative phase; 1.2-2 during flowering. Different varieties of cannabis might require significantly different values of EC.

Thanks for your help


#8

#9

Buckets make horrible pots for plants! I’d suggest getting some five gallon smart pots and moving them asap.


#10

EC and and PPM are both measurements for Total Dissolved Solids

Most nutrients supply their own feeding charts and indicate either the TDS PPM EC that they recommend at every week of the grow.

“To obtain an approximate sodium chloride TDS value, multiply the EC reading (in microSiemens/cm) by 1000 and divide by 2. To get an EC value, multiply the ppm reading by 2 and divide by 1000. Thus, if your EC is 1: 1*1000/2= 500 ppm.”


#11

@bob31 Thanks for the reply Bob but I think you misunderstand my question. I was wondering how the solids are replaced does the new nutes in the feed water wash away old nutes and wasted salts or does the soil keep the old nutes that the plant has not used yet and supplements the remaining old nutes with new nutes.
The question is
1 If I water my plants with PH 6.3 and a TDS of 1000 what should the runoff be?
2 Should I see the PH going up or down or in my thinking stay the same.
3 Should the TDS or EC (which ever scale you prefer) be the same as the 1000 PPM that I fed the girls with or would you see a increase from the excise salts being washed out of the soil.

The above article that I posted yesterday goes into that, slightly, and said you will see a small increase in the TDS readings of, the runoff, because it will bring with it the waste salts the plant releases into the soil.

Exerts of a article from a site I will not mention.

“Under normal conditions, the EC in the growing media and runoff should be just a little higher than the nutrient solution in the reservoir. If the EC of the solution drawn from the growing medium is higher than the one from the reservoir, there might be starting a fertilizer salt build-up.
An indicative EC range for cannabis plants is 0.8-1.3 for seedlings; 0.5-1.3 for clones; 1.3-1.7 under vegetative phase; 1.2-2 during flowering. Different varieties of cannabis might require significantly different values of EC.”

Also I would like to apologize for posting a link that appears to break the posting rule setup by the community. In the future I will be more mindful of links and other things that may inadvertently direct people to other sites that may be in competition with the operators of this site.

Thanks Tony


#12

If you have a link that you want to post, just as long as they don’t have competition with ILGM then generally they can be allowed, but you can post the link and tag me or or CB or one of the mods and we can let you know for sure.

I’m a soil grower and TDS is easier to solve for me as I can simply water to runoff each time helping to control the TDS.

If you track the TDS in and out that gives you the TDS of your growing medium If you are using a nutrient enriched soil you will see high TDS from the runoff initially, but as the nutrients in the soil will decline. If the TDS rises, then you are looking at lockout or salt buildups.

I think a chemist would be needed to answer the exact question you have.

It has been my experience that if I water to run-off and my tds in was 1000 ppm and out was 800 ppm, then the soil kept 200 which means next feeding she needs 1200 ppm to try and achieve that 1000 ppm runoff.

All of the TDS values I use are from what the feeding charts of my nutrients recommend. I have not had any issues with nutrient burn or under feeding using those charts and spot checking my TDS.


#13

Thank you @bob31 that is exactly what I was looking for. I know all nutrients are different and recommend different TDS readings but was looking for a rule of thumb on deciphering the readings and you came through.
Thanks man


#14

It isn’t textbook, but it helps paint the picture. I spent about 3 months reading and learning everything I could find on pH and TDS and the relationship between the two and uptake of nutrients and the lack of uptake when the numbers are wrong. There is much to know but the science is pretty solid. @TBrezzy Glad I could help it make sense!