Ebb and Flow need Expert advice

I feed my plants every 2 hours for 30 mins. The whole day even when lights are off.

Three questions:

  1. How long do you flood the system for?
  2. How many feeding cycles?
  3. When do you prune fan leaves?

So people here are the latest pictures of my plants.

I kind of went over board with the pruning of fan leaves, in search of more light penetration and airflow, fml.

First i was suspecting nitrogen toxicity but now im steering more towards root rot, please do guide cause im in the middle of deciding whether i should go back to soil. Got some more seedling on the way :smiling_face_with_tear:, i want a better life for them.

I’ve not feeding them nitrogen for like 2 weeks now so why are the leaves still clawing, pointing towards rot root? I’ve also checked the roots, got slim.

Also these were 4 plants initially in the same ebb and flow tray, i had to axe one because it turned out male and the root and a bit of stalk i cannot get out of the tray ( That would definitely also attract more root rot yes?

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So many things come into play with this. I have a flood system that I built myself. My first thought is too much water, start by cutting all watering out when lights are off. I run my system 3 times a day for 15 mins each time. How old, what nutes, hoping their not autos, have you flushed at all. When mine were around 3-4 weeks of veg I cut down to 2 waterings per day for a few weeks. I am in clay pebbles the hold good moisture, what is your media?


@N00b I do DWC with top water feed and not ebb and flow…I also have each of my plants in their own reservoir and this keeps things simple. Yes if you left that one plants roots in your system after you chopped it could cause issues for the others as it dies off. You said you have not been feeding nitrogen for the last 2 weeks…not sure I agree with that philosophy, MJ needs nitrogen every day to grow. Getting everything down correctly takes time since how you grow is different from how @Flyinbrian78 grows…you have some issues here for sure…how is your PH ?

left is 20 days and right is 30 days


@Retiredoldguy @N00b

Without question leaving the plant that you cut in the watering sequence is not good. A couple things make Ebb & Flow different from the DWC which is really why I chose it over dirt or DWC. EF doesn’t keep the roots submerged which helps reduce root rot. You should be changing nutes in your reservoir every 7-10 days. You also should be using something like UC Roots in your nute mix. As @Retiredoldguy states Ph is critical, water temp is also important, it is best kept under 75. Chew on what we’ve put out there so far and respond back. There is a forum format to use for help that asks details on everything lights, nutes, strands, Etc. My experience so far is there is great advice available on the forum but there doesn’t seem to be a whole lot of hydroponic growers. What you have can be figured out easy enough just need more details. I would also recommend a good top flush with Ph’d water. I too flush mine with 5 gallons of water each every 4th res change.


-What strain, Seed bank, or bag seed (photo or auto)

  • Bag seed

-Age of plant

  • 7 Weeks

-Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF

  • Hydroponics

-Vessels: Type and capacity of container (fabric, plastic, etc)

  • 80 Litre reservoir (Using only 28 liters of water)

-PH and TDS of Water, Solution, runoff (if Applicable)
PH 5.5-6.2 ( I let it drift a bit)

-PPM/TDS or EC of nutrient solution if applicable
On Feb 22nd PPM was 420

-Method used to measure PH and TDS

  • PH pen (HANNA), TDS (Local brand pen) both digital

-Indoor or Outdoor if indoor, size of grow space

  • Indoor (2 by 2 feet)

-Light system List brand and wattage/spectrum

-Actual wattage draw of lights

  • I dont know

-Current Light Schedule

  • 12/12

-Temps; Day, Night

  • 18 Deg C, 6 Dec C

-Humidity; Day, Night

  • 50 Percent Plus always

-Ventilation system; Yes, No, Size

  • No

-AC, Humidifier, De-humidifier,

  • No

-Co2; Yes, No

If growing Hydro some additional questions:

-DWC? RDWC? Autopots? Ebb and Flow? Other?

  • Ebb and FLow

-Distance of liquid below net pot (DWC)

-Temperature of reservoir

  • 18 to 20 Deg C

-TDS of nutrient solution
22nd Feb PPM 420

-Amount of air to solution

  • I dont know, 1x air pump which bubbles 24/ 7

Man i don’t know about doing a full nutrient water change every 2 weeks, seems like a lot of work. But i’ve read about this rule of thumb where you keep topping off the solution till the topping off equals the solution volume (i.e. If the res was 80 Liters and you topped of for about 2 weeks, which incidentally equals 80 liters, its time for a full res change). Also i heard people get away with doing only 2 or 3 full nutrient changes but that’s learned from experience.

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How often do you do a full reservoir change?

I had a big one in DWC but i decided to transplant it outdoors when it was flowering (along with other signs of distress), desperate times, desperate measures.

@N00b my reservoir is a 12 gallon and I fill it with 4 gallons of nutrients. I have 2 air stones and a circulation pump inside the reservoir. I drain/empty the reservoir every 10 days for the first 2 times then every 7 days after that. Until the plants are about 60 days old I usually don’t have to add any nutrients between draining’s but once they start drinking they will take in a gallon a day so I must add nutrients to make it to the 7 day mark. I have been using this system for 2 years now and I like the simplicity and ease of maintenance.

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Your air pumps need to be higher than the water level…
If you loose power and they are below the water line , you run the risk of them siphoning out all of the water in your systems… :+1:t3:
Nice job…
:v:t4: :sunglasses:


@N00b @Retiredoldguy Looking at what you have listed, I lean towards root issues. You didn’t list nutrients if you are using, any that I saw anyway. PPM wouldn’t seem to be an issue at that level, Ph wouldn’t seem to be an issue at your listed ranges (assumption your meter is calibrated). If we look at it as a root issue the first thing I would do is get the plant that you cut out of the water circulation. Change your rez water, top flush the plants with water that is Ph to 5.8 or so. Clean your rez good make sure it is clean, clean. Fill it back up and add something similar to UC Root. I suspected I had a root problem early on and changed my nute recipe. I added the Armor Si and the UC Roots and haven’t had any issues since. Does your water, medium and grow containers stink? That is a good sign of root issues. How long have you been on 12/12 light cycle, was it an issue before switching to 12/12?

Actually i started with some seedlings that were having rot issues earlier in their life, when i switched to ebb and flow and fixed the feeding time. ( 30 Mins every Hour or so). The plants recovered and were doing well upto the 12/12 schedule.

What i’m guessing is the roots are bound now, and they dont let the water drain that easily, hence they remain real wet for a longer time now.

What i’ve done now is reduced the feeding time to 15mins every 2 hours when the light is on and only once when the light is off ( 5 feed cycles during the Light on phase, 1 Feed cycle during the light off phase). Added a fan. I could take out the plant i cut, but ill probably mess up roots of the other 3 plants, cuz the roots have intertwined quite nicely.

I would use Hydro Guard and UC roots if they were available here, but i believe the problem here is more with the feeding routine and the grow tray (root bound).

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Using air stone pumps, they dont siphon water.

You use Hydro guards or UC roots? Anything that prevents root rot?

How long do you feed for? How many times do u feed in a day?

Can you explain some more?

@N00b I will share my feeding chart …this is the General Hydro Flora series and is put in 4 gallons of distilled water but you should be able to adapt it to your line of nutrients. The 4 gallons I start with in each reservoir gets consumed by the plant slowly in the beginning and so by the 7th day I still have a couple gallons left in the reservoir…I need that much to cover the air stones and allow the circulating pump to work. but when she gets to stretching and putting out buds she will drink a gallon a day and so by the 3rd day I am adding nutrients to make it to day 7…I like to only add/refill once if possible between changeouts…what you are experiencing with ebb and flow is some of what I see my friend encounter…plants closest to the input flood pipe get all the nutes and grow fast and the ones at the back end get what is left but he likes it cause he can grow many plants at a time.

nutrient schedule

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Man don’t have many hydro shops here, but i found this Trichoderma harzianum, it is supposed to be a fungus that promotes beneficial bacteria and prevents root rot. Worth a try right?


@N00b absolutely try it…having a root inoculant is important…and for sure you are asking to harm your girls if you don’t use some kind

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When you add nutrients, in between res changes (topping off) you are typically trying to maintain the same PPM right?

absolutely same nutrient mixture I started with unless close to changeout day and then I might just add 6.0ph distilled water 0PPM no nutrients

So if u started with a 2g 2g 2g mix in 5gals, when you top off you use the same ratio but less nutrients obviously because you’re topping off with maybe for example 1 gal of water. Am i correct?

yes you have it correct…I find it easier just to make another 4 gal bucket instead of something smaller…it will get used

@N00b I don’t want you to get caught up in exact nutrient PPM when you are replenish your reservoir…as long as you in the general range all will be good and if out of it you will be changing it out before it could cause any issues if any… we all have our mixtures that I have shared above and these will yield around 200PPM for seedlings going up to 300PPM and then 400-700PPM for vegitative and up to 900 for flower…this works in my setup some may say it is on the low side but my girls grow just fine