Ebb an Flow SOG advice needed

[KushKrew]

Hi Guys,

Figured I was asking the WRONG questions, it's a great old Diesel-fuelled Sunday... Some copy-paste here so I apologise for plagiarising myself.

So I've got an interesting situation I've never been in before. I want to do a SOG, cropping every 2 weeks, 8-week cycle. I'm kitted out for cropping every 4 weeks, though, figure I can use my current system a bit differently, but:

I have got 2 tables at 60cm by 120cm, and 2 reservoirs. I figure if I go for a system using my usual 20cm pots, I can add 9 clones every 2 weeks, no veg at all. Using coco coir at the moment. But I have a whole heap of rockwool here, seriously I have shitloads left over from doing some acoustic treatment. I also have more than enough expanded clay pellets from my old top-feed system.

My concern lies in the fact that in each table I will have plants from 2 'phases'. I am not too concerned about table no 2 as from week 5 their water needs stay pretty constant, but from week 1 to 5 there is a LOT of growing going on, and what I am scared of happening with the coco pots is that by the time I have plants in week 4, they'll be getting dry OR week 2 babies will be getting too wet. So in other words, weeks 1-4 would need to get the same watering times, and week 5-8 also.

So I'm actually trying to figure out which medium would be most forgiving to this method. Any advice would be appreciated, I know trying is the best way to learn but hell I hate plants suffering.

I know I can simplify things a lot by going for a 4-week cycle, but what can I say I've ALWAYS wanted to do a 2-week perpetual harvest and I want to give it my best go with what I have. If I'm being a dumbass and this is a futile pursuit let me know. Will settle for 4 week crops then I guess, grudgingly....

Currently on the job market so upgrading is out of the question right now, even little things. Keeping the belt tight for now :/

Thanks for your time!

 

[penguinking]

you have a few options, and no its not a futile effort, just more work. depending on your feeding schedules, you can achieve a two week turn around. my very first thought would be using a medium that will retain some moisture, such as perlite and coco. after that you could hand feed all your plants exactly what they need, albeit time consuming as hell. the second thing i think of is simply having 4 flood trays on four different resi's. is there any way that you could incorporate a drain to waste system? im assuming youre doing a recirculating hydro set up... if you drain to waste you wont have to worry about your different nutrient mixtures mixing up in the res. it is doable, you just have to use your head a lil and be prepared to mix 4 different nutrient solutions every time. growing perpetually can get tricky and a LOT of work and maintenance. good luck though

 

[KushKrew]

I'm kinda hoping it turns into a LOT of work man... Our economy's a tad broken so I need to keep my hands busy while on the job market, being the wrong season for finding work in my field I can see myself going crazy with boredom.

Drain-to-waste is very easy for me to set up indeed. I just feel that in my current position I'll be crying watching all the nutes run to waste...

Thanks for the response, man, now I can go at it with a bit more confidence. Like you point out, it might take a lot of tweaks, but I'm sure I can get there. I think budgeting for an extra two tables in future is going to be not only wize but probably the only solution for the way I like to do things.

Have an EXCELLENT day!

 

[Oo S0uP oO]

Totally attainable(Better fucking be cause thats what I plan on doin), couple things though;

1. Make sure that rockwool your talking about using isnt chemically treated (All of it is unless its meant for grow medium I think) We use it in construction all the time for fire rating and I cant see how acoustic application would require any less QA demands it all comes from the same kinda suppliers. If its treated it will never be inert and will kill your plants.

2. This is highly dependent on strain choices or more appropriately timing of said strains as you wouldnt want any shared table with two strains on it concurrently (At least I wouldnt) which means everytime you want to switch strains you would have to leave a two week gap as a buffer on the table. Easily written off as mother recuperation time though

3. A good medium for this would be Mapito, its reusable, holds moisture well, but it is incredibly hard to over water your root system (Google Mapito grow medium as your not likely find any suppliers locally) I plan to use smart pots and layer the top of the medium with lava rock so as not to allow it to float back into my trays. I dont anticipate changing my flood schedules at all weeks 1-8.

Id like to see how this goes. You have a bit of a head start on me as I have to finish the experiment Im working on now before I start but Ill be back to compare notes...~S0uP

 

[penguinking]

yo kush krew, if you only feed them to wet the medium you will have only minimal runoff. this is why i suggested a coco and perlite medium becuase you could water every other day and hardly "waste" anything at all

 

[MrMeanGreen]

I am a bit perplexed. You talk about under and over feeding. Flood and drain, you can't over feed if your flood levels are set right. How are your plants drying out?
The flood level comes up to about 1 inch short of the the rockwool. I flood every hour for 15 mins. So long as the the top half of the main root ball is not submerged during flood, your plants will get all the oxygen they need and never drown. The only thing that differs from tank to tank is nute levels.

What I would add is that if you can, veg them for a week or so, that little bit of time makes all the difference with the rootball size and therefore your yield. It can get a bit tricky giving you plants the lumens they deserve due to varying plant heights through the grow. I also found that if your need to keep each of your 4 grows in seperate tanks as when it comes harvest I had problems with wandering roots intertangling and doing damage to younger plants when pulling the mature ones.

 

[Mithrandir420]

Absolutely you can over feed. You can over feed in ANY system.

 

[MrMeanGreen]

Absolutely you can over feed. You can over feed in ANY system.

I am not talkin nute strength or EC levels, I am talking time flooded. NFT... How do you over feed NFT. Like I said, if your flood levels are right, there is no over feeding. F&D tanks can run all day long if you want, but is counter productive with regards to pulling oxygen over the roots during the flood part of the cycle.

 

[Mithrandir420]

That's called overwatering.

 

[penguinking]

if youre using a medium that will retain water such as a soilless mix it can most def be over watered on a flood and drain table, regardless of how many airstones are in the res

 

[MrMeanGreen]

To maximise benefits of F&D you need to use hydroton, perlite or similar. rockwool and coir retain water and you don't want that. flooding feeds water and nutes, draining floods your roots with oxygen. Even when drained, hydroton or perlite will retain enough water to keep your humidity in the pots and roots at 100%.

I really don't understand why anybody would use coir, rockwool or similar. You obviously don't truely understand the benefits of F&D.

OP. this will resolve your watering issues, you can flood as often as you like and nothing will drown or be overfed (assuming nutes are correct) regardless of the differing ages of your plants.

Also.... if you can, veg for 1 week. The difference is massive just giving your roots a few days to get going especially if you have just transplanted.

Also also... If your tank doesn't hold enough to flood all your tables at once simply use seperate pumps. ie feed table 1+2 then feed 3+4.

 

[ringlead3r]

Use hydroton it will give u best growth more feedings harder to over water but u have to have larger rez due to higher flood height s