proper ph for coco

Hello: I am currently growing in coco. My plants are a couple of feet high and in in the 3rd week of flower stage. Some indica, some sativa. They are in two gallon smart pots. I water with nutes every 3 or 4 days when the pots are light and the coco has become kinda dry. I give each plant about 12 cups of water/nutes each watering and receive about a 20 percent runoff to waste. Every fourth/fifth watering I use only water ph'd to 5.9 or real close.

I have experienced burning edges of the leaves progressing to burning the whole leaf and then the leaf dies. Many leaves are still green, but the burning/browning is really bugging me. The room is well ventilated and the 1000 watt HPS is about 18 in to 24 inches from the tops of the plants. 70 to 80 degrees fahrenhite and about 40 to 65 rh.

I have had this problem for a couple of months, starting in veg and continuing to the present. I know I should have done something earlier, but oh well.

Anyway, I read the sticky on ph and I have some questions. The water from my hose reads about 300 ppm and about 7.5 ph. I add my General Hydroponics flora grow, micro, bloom at about half strength which brings the ppm to about 900/1000 and the ph to 6.4. I have also used CalMag at about half strength each watering.

I then ph down to a 5.9, water/nute the plants, and check the runoff which ph's to 5.2.

Is this good? I don't think it is. If it isn't should I ph up to about a 6.6 ph after adding the nutes? Would this bring the ph of the runoff to 5.9?

The PH STICKY indicates that soilless ph should be 6.4. Is that the ph of the water/nutes that goes into the pot, or should that be the ph of the runoff?

I am also looking for the acceptable range limits of the ph of the water/nutes going into the pots, as well as the acceptable range limits of the ph of the runoff.

thank you, issac

This post is to help with my first post on this thread. Isaac

What is your experience level? novice

Your Equipment:
.1) Type and wattage of lights. 1000 HPS
.2) Distance from tops? 18 INCHES TO 24 INCHES
.3) Reflector type? ENCLOSED REFLECTOR
.4) Is there a consistent fresh air supply? YES
.5) Do you have an exhaust fan and a circulation fan? YES
.6) What are the bulb wattages, kelvin ratings, and schedule? 1000 HPS

Your medium:
.7) Specific brand and type of soil, COCO DON'T KNOW WHAT KIND. NOTHING ADDED.
.8) Size of container. TWO GALLON SMART POT
.9) Did you use peat pucks (or similar) to root clones or germinate seedlings? YES, ROCKWOOL SQARES TO ROOT CLONES.

Your nutrients and water:
10) Source of water? TAP WATER. What's it's ph before adjusting? 7.3 FROM HOSE. 6.4 AFTER ADDING NUTES.
11) Method of checking water ph. PH PEN
12) Method of adjusting water ph. PH DOWN
13) Specific brand and N-P-K ratio for each bottle.
GENERAL HYDROPONICS FLORA GRO 2-1-6 2 MILL PER GAL
FLORA MICRO 5-0-1 3 MILL PER GAL
FLORA BLOOM 0-5-4 5 MILL PER GAL
WATER/FEED TUESDAY, SAT, WED, SUN KINDA SORTA. DEPENDS ON WEEK
WATER WITH 12 CUPS EACH PLANTS WITH 20 PERCENT RUNOFF.
List dosages (quantity per gallon) and current feeding schedule.
14) How often are you watering between feedings, and how much per watering? I FEED EACH TIME I WATER.
15) Any additives or tea's? USE HALF TO FULL STRENGTH CAL MAG. ALSO 2 MILL PER GAL PROTECT.
16) Are your ph levels stable, or do they fluctuate? WATER FROM HOSE IS STABLE PH.
17) What is your ingoing water's ph? 5.9...your runoff ph? RUNOFF IS 5.2
18) Do you foliar feed? NO FOLIAR SPRAY

Your growroom:
19) INDOORS
20) 8X8 FOOT ROOM
21) What are the temps and humidity levels while lights are on/off? 24 HOUR CYCLE 70 TO 80 DEG FARENHEITE. 40 TO 65 RH
22) Have you seen signs of insects in the growroom? NO INSECTS

Your strain:
23) What strain are you growing? SOME ARE INDICA SOME ARE SATIVA
24) From seeds or clones? FROM CLONES
25) Is this an autoflower strain? DO NOT KNOW

I'm no expert, but have used coco so I'll take a shot.

I found that feeding with every watering gave me the same symptoms that you are seeing.
With coco, a little dab will do ya.


Coco is a unique growing media.
Some call it "solid hydroponics" or 'ponics in a pot.
That is misleading.
It handles nutrients quite differently than real hydro.
It stores them briefly and then hands them off to the plant.
If you continue to feed faster than your plants can use, the coco will keep storing and concentrating the compounds.
Burns their little feet it does! :)

And the same goes for CalMag.

My tap water runs about 120 ppm and it's volcanic groundwater.
(Has very little Calcium)
And I found that 1 tsp. CalMag per Gallon, once a month, was too much.

With a 300 ppm tap water, I seriously doubt that the CalMag is even necessary in your case.

My advice?
Stop the CalMag, cut your nutrients back and alternate with plain PH'ed water.
With coco, it's best to pre-treat it, then wait until your plants indicate that they have needs again.

I wait until the new growth gets just a tad pale, then feed sparingly.
Works a treat, my plants are bigger and healthier than before, with much less feeding!
And there's no more leaf-tip burn either.:cool:

Hadda bail on coco though, my local store started carrying the cheaper, salted-up, crap.
Fixable, but too much like work.

Now using Sunshine mix #4 and am quite happy with it.

Aloha,
Weezard

thanks for your two cents, weezard.

what about the ph scenario that I set forth? do you think the 5.9 in with a 5.2 runoff is okay, or??????????

isacc