Flood Height critical with coco?

[Thowywowy]

Im running a mix of 1part perlite 1 part lava rock 2 parts coco on my trays with great results. VERY forgiving, I could literally go 5+ days without power and the plants would still be very much alive. Granted it would throw off the lighting cycle, but the plants would not die from lack of h20.
Back to the point, 2 of the trays flood roughly 3" high, which is what I have always done with my e&f setups. However, the other 2 trays only flood around a half inch. Its just enough to keep the medium moist.

Granted the high o2 levels present in coco, do you think it matters that 2 of the trays only flood a half inch? One of the things that is great about e&f is the fact that with every flood and drain cycle you are bringing fresh o2 into the rootzone. With only a half inch flood this is clearly not being accomplished.

The plants are quite healthy, but I am worried that the difference could show itself in the form of a lower yield compared to the other trays.

 

[Guest]

Maybe give em a deeper flood once a week to soak out any hot spots and get the O2 in there???
My last grow was a flood & drain to waste and this is what I did. The other days the flood came up about an inch on the pots then once a week I'd flood em to about 2inchs below the top or higher. This system worked well.
Peace.

 

[gaiusmarius]

your worries are fully justified, maybe you can do a hand flush from on top once a week or every 2 weeks. but as you say, by letting the water only raise so little you are not accomplishing a full o2 change, which will make a difference to the yield. how much difference it makes will be interesting to find out, coco is very forgiving and adaptable after all

 

[coolx]

how often do you flood? I'm growing on coco mats for the first time and i may be overwatering them. I water every 8 hours (my meter's longest interval) up to about an inch. I've been told the idea is to just get the bottom of the pot wet and it will draw the rest up by osmosis.

 

[Caligrown]

DO. (disolved oxygen) I am working from logic here but It seems that if your nute solution were oxygenated and the plants were drawing the water into the coco that it would be delivering O2 to the roots.

Of course this is a guess so I would say keep an eye on them and tell us if you need to delivwer oxygenated water from the top or if it is OK????

I love to hear data based on experience.

Thanks Man

LOVE -Jay

 

[Thowywowy]

At present I am flooding them once daily at the begining of lights on for 10 minutes and I am planning to continue this regimen as its plenty to keep the medium quite moist. The plants do get a flush 1-2 times a week when I top off the res because I add the water by dumping it into the trays which in turn floods them 3-4 inches. I would also like to note that the nute solution stays in right around 60F, so there should be plenty of DO present. But is there plenty of DO present in the medium, thats what I am concerned about. The plants are exhibiting no signs of overwatering, so common sense tells me that indeed there is plenty of DO in the rootzone.
At present I am doing exactly what you are doing coolx, although I am flooding far less frequently. As to whether you are overwatering, I believe the plants will tell you if you are overwatering, and I also believe it is quite hard to overwater in coco assuming you are not keeping the medium submerged. That said, I would also say that if you are only flooding them an inch, and the medium does not ever come close to drying out, there would be no benefit to flooding multiple times a day. Granted this is just what seems logical to me, coco is very much new to me so take this for what its worth.

I appriciate the replies, I believe I will leave everything as is for this cycle and see what happens. In a couple months when all is said and done I will try to report back with the results compared to the other trays.

 

[gaiusmarius]

i was not talking about DO i was talking about normal air. this is one of the things about coco, every time you fill it with water and allow that water to drain off freely, you are replacing, not just the nutes and water in the coco, but also the air. when the coco fills with water all the air present is pushed out by the water. as the water drains off air is sucked in to replace it there by replacing the used up air with fresh air. that's why coco can be, indeed loves being, water many times per light phase. that's why it works so well, when treated as a hydroponic medium.

so if you have an ebb and flow setup that only ever lets the water flood half an inch up the pot, then you are not making the most of the coco, as the air in the top part f the coco will become stale.

 

[coolx]

tx for the feedback thowy - as it's my first hydro grow, I really have no idea what I'm doing ... I decided to handwater them for a while to try to get them healthy again ... once every few days with organics alive and H&G's root excelerator and A & B nutes, and I've also moved the lights away as all the plants are showing bleaching - I had 750W digis 20" away - I moved them to 30". I think maybe the roots aren't strong enough.

 

[Thowywowy]

@all

i was not talking about DO i was talking about normal air. this is one of the things about coco, every time you fill it with water and allow that water to drain off freely, you are replacing, not just the nutes and water in the coco, but also the air. when the coco fills with water all the air present is pushed out by the water. as the water drains off air is sucked in to replace it there by replacing the used up air with fresh air. that's why coco can be, indeed loves being, water many times per light phase. that's why it works so well, when treated as a hydroponic medium.

so if you have an ebb and flow setup that only ever lets the water flood half an inch up the pot, then you are not making the most of the coco, as the air in the top part f the coco will become stale.

Exactly, and this is the question that I am posing in this thread.

I would also like to note that the nute solution stays in right around 60F, so there should be plenty of DO present. But is there plenty of DO present in the medium, thats what I am concerned about. The plants are exhibiting no signs of overwatering, so common sense tells me that indeed there is plenty of DO in the rootzone.

Perhaps I used the wrong terminology (or rather I did in fact use the wrong terminology), as the roots are not submerged it would not be dissolved oxygen but rather oxygen levels in general that I am worried about. But this is the root of my question. Thus far it looks very promising, but there are still many weeks to go. Bud development is equal to the trays being flooded 3-4" at the 15-20 day mark.
I certainly agree with you that I am not getting the most out of the medium, but the question becomes, am I getting enough for a decent harvest? Will there be enough of a difference to justify the higher flood depth? Remember, with a lower flood depth the resevior can be smaller, or a larger resevior will last longer before it requires topping off. For people such as myself who cannot attend to the grow on a daily basis this is very important.
@coolx
again I am very new to the coco thing, but if your plants are not healthy I would reduce the flood frequency to once a day or maybe even once every other day. I recently had a timer failure and had a tray go without a flood cycle for 4 days. Did not lose a single plant, and the wilting I did see was minor. I am confident they could have gone another day at least without losing any plants. And this is with the medium roughly 2.5 feet from 1k MH lamps, no glass or aircooling. This is SOG, plants are only a foot tall and the light is around 18-20 inches from the closest plants. Lights on temps in the mid 70s, lights off temps in the low 60s to high 50s. RH around 40%. Just to give some background info for a basis. :wink:
But of course if your plants are not healthy start with the basics always. PH and PPM levels, not only in the nute solution but more importantly in the medium. You can test these levels by handwatering and measuring runnoff. Given that you using the matts, this may be a bit of a challenge. But if possible, this will give you and answer to your problem 9 times out of 10.

 

[gaiusmarius]

well it's to be hopped that the coco being the adaptable medium it is, combined with a vigorus plant should mean that your yield doesn't suffer greatly, specially if as you say, the plants are looking equally healthy.

have you got some pics? i'd love to see how they compare with eachother.

peace

 

[Thowywowy]

gauismarius thank you so much for the replies. Yes I do believe at this point that my yield will in fact not suffer much if at all. Although I will not be able to tell definitively until after a couple runs have been completed, I can say that things are looking very promising up to this point.
To further explain, the trays that are only being flooded around 1 inch are also a slightly different method than the other trays. Half of the grow is a low density sea of green with a plant spacing of roughly 1 untopped plant per square foot for a total of 16 plants under a one thousand watt metal halide lamp. This half of the grow is being flooded the normal 3 to 4 inches. The other half of the grow is also a low density sea of green but with a twist. The plants are all topped and trimmed to achieve 3-4 growth shoots. I still have the 16 plants per light, but they are in a tighter space, taking up only 9 square feet instead of 16 for a plant density of roughly 1.75 plants per square foot under a one thousand watt metal halide lamp. This allows me to drop the light roughly 6 to 8 inches closer than the other half. Also, these plants are in quart pots, where as the other half are in 1 gallon pots.
As you can probably tell, while the number of plants as well as the method of grow under both lights is similar, there are major differences between the two aside from just the flood depth, making any differences in yield unknown as to the specific cause.
As previously stated, the overall plant health and developement based on appearance is identical between the two. Unfortunately I usually leave the location before lights turn off and arrive after lights are already on which makes taking some good pictures very difficult. However I will see what I can do. :wink:
One thing I would like to mention to all those attempting ebb and flow grows with coco as the medium. Flushing throught the plants life cycle is a must. Everything was going smoothly up until this last visit, which is some where in the neighborhood of 6 weeks flowering for the plants in question. Overferting became apparent, even though the resevior levels are stable, and PPMs are actually a few parts per million under what I know this particular plant can handle. My only conclusion is that there has been a build up of salts within the medium, caused by not flushing the plants a single time during their life cycle. Upon further investigation I discovered elevated ppm levels within the medium. Just a little heads up for others attempting ebb and flow grows with coco as the medium.

 

[Thowywowy]

Flushing once or twice during the cycle is certainly not going to harm anything. :wink:

Here is the side that is flooded less than one inch.



Here is the side that is flooded higher.




Both sides are healthy as far as I can tell. Pictures were taken with lights off.