Bit of crispy yellowness at end of leaf tips

5mls floranova per gallon

that's

53ppm N
46ppm P
77ppm K
26ppm Mg
53 ppm Ca

theres no way that enough fertilizer for a coco plant in full bloom under that much light

if you got salt build up (which is hard to believe) its from not enough volume of solution with each watering not because your over feeding

if you water in 1 gallon(4 liters) at least 0.5 to 1 litre should come out the bottom of the pot each time

the manufacturers instructions on the label for that particular product are actually pretty good and a safe low

most brands tell you to add too much and people always say use half the recommended and that's often true

this particular product the directions are good

Well thats interesting. My PH does go up, my PPM goes up a little bit, i had been attributing that to just a bit of debris coming back from the pots into the reservoir (its recirculating). I'll check my logs but I dont think I ever see ppm going down but again i do spill bits of grit around the drainage tray when I'm fiddling around. I do try to clean it up but only as much as is convenient to do. I have a log of my reservoir but not the drainage contents itself.

Previous reservoir change was on the 29th of June and I had 43ppm water, 590 after nutrients and 727ppm at the end. I think it did this is at 1am because I too more measurements for that day 5.9 / 790 after morning feed, 6.1 / 814 after the evening. Reset ph back to 5.7

29th - 5.7 / 727
29th - 5.9 / 790
29th - 6.1 / 814 (back to 5.7)
30th June - 6.1ph
1st July - 6.2 and 830ppm, set back to 5.8
3rd July - Added 20lt of water added... some (will start taking more detailed log) nutes and ended with 5.7 / 750
4th July - 6.2 / 819 set back to 5.8
5th - 6.1 / 840 back to 5.8
6th - 6.2 / 908 back to 5.7
7th - Added 20lt water 5.8 / 780
9th - 6.1 / 799 back to 5.7

And i did new res on the 10th. I also gave the reservoir a proper scrubbing, rinsed out the pump etc..

So far:
10th - 5.7 750
10th - 5.9 800
11th - 6.2 / 805 (5.8 )
(added 4lt ppm to 745)
12th 6.1 / 775

I'm going to dash down to the hardware store and get some risers for my geopots, they dont drain as well as they should when sitting on the drainage tub directly and I'll watch the 2m watering tonight and see (just by eye) how much is running back out. I'll try to get a sample of it too.

On watering, given the medium (coco/perlite), is it better to water just once per day?

And thanks a lot for your help

im not sure on the best watering schedule for coco and it might vary depending on container size

your log is good

what I would do is take a syringe and draw some fluid out of the medium or squeeze a sample from the bottom
or turn it on to water and grab the first bit of fluid that comes out the bottom of the pot
test the sample
if that ppm amount is significantly larger than that of the ppm going in then your holding salts in the coco

if your holding salts then you need to flush it out

then you need to make sure when you water that you water for a longer duration to get a larger volume of water thru the pot so theres plenty of solution draining form the pots with each watering and then perhaps adjust your water frequency to offset the longer watering duration

if you don't get enough volume of solution thru the pot it will collect salts

but the salt build up is a result of the short watering cycles and not cuz your over fertilizing

normally what youd expect to see in your reservoir if things are working proper is the ppm fall and the ph rise

your getting a ph rise but your also getting a ppm rise

the only other thing I can think of would be if your water source is well water filtered with a water softener that uses salt

or im missing something

it just don't add up

also one more thing

id change your reservoir 1x per week.. it looks like your running it every two weeks which can work if you've got a very large reservoir... but if working with a smaller reservoir id change it more often 1x per week

Ok I've put some risers so the fabric pots should drain better. I ran the pump a lot during this time and now I've got a lot of debris in my reservoir.



My ppm went up to 905 and my ph dropped to 5.6. I'm not sure if ppm meters detect bits of Coco?

Anyway I'll think I'll dump this tank tomorrow and clean all the crap of my drainage tray. I might up the nutes as well from what you have told me. I've shifted the feeding to an 8 minute feed, once per day at the start of the light cycle. I'll keep doing that for a week and check the drainage etc and let you know how it goes. Heres some pics I took when i had a couple of the plants out.



Thanks

I wouldn't increase the ppm of the nutrient until the ph is riseing and the ppm I falling

I would do what your doing ..with using the week nutes... to get the salts removed from the medium

id drop the ppm to maybe 300ppm and water them hard for 30 minutes 1x per day and get lots of volume thru them

then when the ppm begins to show a lower reading than what you started and the ph is rising then go back to full strength and water 20 minutes each time

Ok first go at this. The pharmacy didn't have any syringes so i had to furiously pump my dropper lol. I just watered down my reservoir to about 510 ppm, flushed out the drainage tray, i noticed one plant was getting just a trickle of water so fixed that too. Pots have lost that soggy feel now that they are on risers

The PPM shot up to the low 700s before dropping back to the high 600s. The ph moved down a smidge from 5.7 to 5.6. Hopefully a better result tomorrow.

I opted to just flush my pots out with ph 6 water. I did it twice and got the run off to about 250ppm. Started a new reservoir at 980ppm. First watering saw the ppm drop about 200 but since then its just been yo-yo'ing between 730-770, My ph is going down a little bit, about 0.2 over 4 days. The plants are using a lot of water, lost more than half my volume in 3 feeds so that might account for why the ppm isnt dropping? Ive just added another 30 litres (7.9g) and set the ppm to 800.

Otherwise the plants are doing fine. Buds are fattening up and starting to cover up large parts of stem.

worldspawn said:

I opted to just flush my pots out with ph 6 water. I did it twice and got the run off to about 250ppm. Started a new reservoir at 980ppm. First watering saw the ppm drop about 200 but since then its just been yo-yo'ing between 730-770, My ph is going down a little bit, about 0.2 over 4 days. The plants are using a lot of water, lost more than half my volume in 3 feeds so that might account for why the ppm isnt dropping? Ive just added another 30 litres (7.9g) and set the ppm to 800.

Otherwise the plants are doing fine. Buds are fattening up and starting to cover up large parts of stem.

Click to expand...

sounds like you got a handle on it

if your reservoir ppm is flat and your ph is flat your somewhere in the middle between perfection and possibly over feeding...

I would rather see the ph climb slightly and the ppm drop slowly to reduce the need for frequent/weekly flushing so dropping down to 800ppm was a good call

make sure you getting plenty of volume thru the pots when you water.. it may even require a second drip line for each plant if need be

if theyre drink quickly thatll reduce the ppm requirements and increase the reservoir change frequency

personally, if my reservoir got below 50% I would just dump it and refill a fresh mix

if you set up your reservoir to mke it super easy to change out youll do it more often and be happier
ive attached a valve to the reservoir and let it drain like a bath tub and ive used the pump to drain it, which ever works

The PH is weird. It used to go up all the time, the coco buffered it a lot i think its just worn out lol. In the beginning it used to runoff at 6.6-8 now it just sits still. I'm pretty sure my volume is ok, I've checked all the feeders and its an ample flow and running for 20 minutes they get everything nice and wet.

My reservoir is set up in a similar way. It could be a be a bit better perhaps. My drainage line has another line coming off it with a valve (and a long pipe). I dont like doing it because I feel dodgy doing it, i run this pipe out the back of my garage into the common area of where i live and drain into the storm drain. I prefer to do this at 12am lol. The annoying bit is getting that last bit of water out requires me to detach the reservoir so i can upend it, then scrub it out a bit at the sink.



I'll get into the habit of doing a full change more. Things are certainly much better than before where the ppm was moving up every feed.

I had an idea for some automation of watering. Create a riser for the plants that sits on a load sensor. Then have an arduino read the sensor and turn the pump on if the weight drops below an amount.

the reason for the run off with each watering is to replace the fertilizer salts in the medium

if its watered well but doesn't have run off the salt will accumulate
if its watered with run off the old salts would be pushed out of the medium and replaced with the new input

of course each time your solution makles a pass thru the plant the elements or ratio of elements inside the solution changes

the plant picks up what it wants and leaves behind what it don't , so the older the reservoir mix the further the fert ratios will be from ideal

frequent (weekly) changes also helps avoid root disease

Your in good hands with satori. I seen people criticizing earlier and it kind of pertains to this thread. Is it possible to burn tips on a lower ppm with the wrong mix of nutrients, then a higher ppm of the right blend be fine?

satori, you first and second sentences aren't correct. using a flush with fresh nutrients doesn't necessarily wash out old nutrients and replace them with new ones. This is a coco grow. molecules of old nutrients can remain trapped in the coco, and new nutrients can be washed right through the coco and wasted in the runoff. You really don't know what you're saying.

polishpollack said:

satori, you first and second sentences aren't correct. using a flush with fresh nutrients doesn't necessarily wash out old nutrients and replace them with new ones. This is a coco grow. molecules of old nutrients can remain trapped in the coco, and new nutrients can be washed right through the coco and wasted in the runoff. You really don't know what you're saying.

Click to expand...

Just trying to learn here, with coco how do you get them to decide to change up what they will absorb?

polishpollack said:

satori, you first and second sentences aren't correct. using a flush with fresh nutrients doesn't necessarily wash out old nutrients and replace them with new ones. This is a coco grow. molecules of old nutrients can remain trapped in the coco, and new nutrients can be washed right through the coco and wasted in the runoff. You really don't know what you're saying.

Click to expand...

lmao

I mean I'm sure it's not magic but I'd think you would be slowly working to adjust the balance of nutrient within the coco.

Accumulation in the Rooting Medium


It is well known that with each application of a nutrient solution to a rooting

medium, whether inorganic (sand, gravel, perlite, rockwool, etc.) or organic

(pinebark, peat, coir, etc.), an accumulation of unabsorbed ions takes place.

This can be observed by monitoring the EC of the solution exiting or in the

rooting medium following a sequence of nutrient solution applications. When

that EC measurement reaches a certain level, it is recommended that the

rooting medium be leached with water to remove the accumulate. What is

not as well known is that another type of accumulation occurs — the formation

of precipitates consisting mainly of calcium phosphate and calcium sulfate.

As those precipitates form, additional ions can be adsorbed on their surface

or chemically combined with the forming precipitates. These precipitates do

not contribute to the EC of the medium solution and are not easily leached

from the rooting medium by water. The elements in the precipitates then

begin to contribute to the elemental nutrition of the growing plant. Roots

release acid into the rhizosphere surrounding the root, which dissolves a

portion of these precipitates. With time, the accumulated precipitates begin

to more strongly influence the plant element nutrition than that being applied

by the nutrient solution for some elements. This partially explains why growers

seem to lose control of the nutritional character of their crops over time.

this is a good summary of the chapter you might find useful;


1. In general, most nutrient solution formulations are not well balanced,


particularly with regard to the major elements, N and K.

2. The total elemental concentration in most nutrient solutions is higher than

can be justified in terms of meeting crop requirements. Most nutrient

element insufficiencies in plants are due to ion imbalances in the applied

nutrient solution rather than due to a deficiency of one or more elements.

3. The atmospheric demand should be a determinant of the total elemental

concentration of a nutrient solution as well as a factor in determining the

frequency of application (the higher the atmospheric demand, the lower

the element ion concentration should be in the nutrient solution with

increased frequency of application).

4. There is justification for designing the nutrient solution delivery system

so that only water can be applied, particularly during periods when the

plant atmospheric demand is high. Also being able to easily change the

dilution ratio during the delivery of a nutrient solution would be a very

useful factor.

5. The concentration of P in most nutrient solution formulations is about

twice that needed and may be the primary cause for some plant nutrient

insufficiencies among the micronutrients Cu, Fe, Mn, and particularly Zn.

6. The concentration of N in a nutrient solution may be the primary factor

determining fruit yield and quality (the higher the N, the lower the fruit

yield and poorer the fruit quality). In general, the N content of a nutrient

solution should be at the lower end of the recommended formulation

amount and should be adjusted based on atmospheric demand — the

higher the demand, the lower the N concentration in the nutrient solution.

7. The ratio between K and Ca in a nutrient solution is probably a major

factor determining fruit yield and quality. That nutrient solution elemental

ratio for most crops should about 1 to 1.

8. The use of chelated micronutrients may be the primary cause for deficiencies

of the micronutrients Cu and particularly Zn in plants.

9. Insufficient Zn in most nutrient solution formulations may be the primary

cause for low Zn levels in the plant. It is recommended that the Zn amount

be double that specified in most nutrient solution formulations. It should

be remembered that high P in a nutrient solution will inhibit Zn uptake

and distribution within the plant. The use of chelated Fe is also a contributor

to lower Zn uptake and distribution within the plant.

10. The inclusion of NH4-N in a nutrient solution formulation can enhance the

uptake of NO3-N, which can be either beneficial or detrimental. The amount


of total N in a nutrient solution formulation can be reduced by 10 to 20%

if 5% of the total N in the nutrient solution is NH4.

The Nutrient Solution 115

11. The adjustment of the pH of a nutrient solution to a particular point is

unjustified unless the pH is outside the desired range between 5.2 and

6.5. It should be remembered that the pH in the immediate area around

plant roots is determined by the roots themselves.

12. The adjustment of a nutrient solution to a particular EC is probably not

justified unless there is a compelling need to restrict water and nutrient

element uptake.

13. The accumulation of elements as precipitates in the rooting medium,

whether the medium is inorganic or organic, can have a significant effect

on the plant’s nutrition with time. Therefore, reducing the concentration

of most elements is justified, particularly Ca, Mg, P, S, and Mn, in the

nutrient solution being applied with time.

14. The requirement for leaching a rooting medium due to the accumulation

of unused elements can be significantly reduced by carefully adjusting the

nutrient solution formulation and frequency of application as well as having

the ability to apply only water for meeting high atmospheric demand.

15. An EC measurement of the solution exiting the growing medium or that

within is used to determine when the rooting medium requires water

leaching. That requirement for leaching should be viewed as a warning

signal that the quality of nutrient elements being applied at greater than

that required by the crop. This leaching requirement can be significantly

reduced if greater care is used in formulating and applying a nutrient

solution — the ideal is that no water leaching is required. An elemental

analysis of exiting or retained nutrient solution will indicate which elements

are accumulating, providing guidance in reformulating the applied nutrient

solution in order to minimize this accumulation.

16. The reuse of a rooting medium can pose a problem since that medium

will start with a significant nutrient element charge from the accumulation

of nutrient elements as precipitates that can not be removed by leaching.

17. In a closed nutrient solution system, the nutrient solution must be filtered

and sterilized between applications.

18. A nutrient solution should be assayed for its elemental content when

initially made to ensure that all the elements are within the specifications

of the formulation. Errors in selecting and weighing ingredients and mixing

when preparing stock solutions can be easily made, and the malfunctioning

of dosers (see Figures 7.4-1 and 7.4-2) is not uncommon

Regulating Water and Nutrient Element Requirements


There are two basic systems of nutrient solution use:

An “open” system in which the nutrient solution is passed through the


rooting vessel and discarded

A “closed” system in which the nutrient solution is passed through the


rooting vessel and then collected for reuse

Both systems have advantages and disadvantages. The major disadvantage

to the “open” system is its inefficiency due to the loss of water and unused

essential elements, since the flow of the nutrient solution is greater than that

required by the plants. For the “closed” system, the nutrient solution can be

substantially changed when passed through the rooting vessel, requiring some

adjustment in volume (replacement of lost water) and pH and replenishment

of absorbed essential elements (Hurd et al., 1980). In addition, any disease

or other organisms picked up by the nutrient solution in its passage through

the rooting vessel will be recirculated into the entire system unless removed

or inactivated by some form of nutrient solution treatment. The controls and

requirements for a recirculating hydroponic system have been discussed by

Wilcox (1991), Schon (1992), and Bugbee (1995).

The nutrient solution is expected to provide both water and the essential

elements needed by the plant in its flow through the rooting vessel. It is easily

and erroneously assumed that these two physiological requirements, the need

for both water and essential elements, occur in tandem. On warm days when

plants are transpiring rapidly, however, only water may be needed to meet

the atmospheric demand, while the nutrient elements in the nutrient solution

may not be required by the crop in other than their usual amounts. The

consequence is that the need for water is out of phase with the feeding cycle.

This juxtaposition of events poses a major problem, as it is not common to

have a water-only system operating in parallel with the nutrient solution

delivery system. Therefore, increasing the circulation of the nutrient solution

to meet the demand for water may lead to an elemental imbalance and an

undesirable accumulation of unwanted elements.

With automatic control (Bauerle et al., 1988; Berry, 1989; Bauerle, 1990;

Edwards, 1994) and an “open” system, it is possible to modify the nutrient

solution composition by adding water into the flowing stream of nutrient

solution passing through the rooting vessel, thereby reducing the nutrient

element concentration. With a “closed” system, a delivery–collection system

would be required to pass water only through the rooting vessel. Such

“engineering” aspects of hydroponic culture have recently been discussed by

Giacomelli (1991).

For most of the commonly used hydroponic growing systems, the cycling


of water and nutrient element availability are not easily controlled. As a

nutrient solution is introduced into the growing medium, three things occur.

Plant roots absorb the water and nutrient elements in the nutrient solution

at varying rates (Bugbee, 1995), water and nutrient elements not absorbed

begin to accumulate in the rooting medium (Jones and Gibson, 2002), and

some of the applied water and nutrient elements leach from the rooting

vessel.

JohnDoeTho said:

Just trying to learn here, with coco how do you get them to decide to change up what they will absorb?

Click to expand...

You don't get plants to change up what they absorb, except for changing their light cycle from veg to flower. Otherwise there's nothing you can do to alter what plants take up. All you can do is be careful how much you give them if you are feeding them from fertilizers in containers. If you want a relatively worry-free grow, don't use coco but consider using what is commonly called "super soil," where the nutrients are all placed in the soil and you let the soil sit for several months to give bacteria a chance to break the compounds down to a molecular level that plants can absorb. This is how the feeding process works in nature. There's nothing wrong with feeding from containers, but you just have to be careful how much you give and how often you give it. The good news is you'll learn over time.