How to regulate reservoir?

To cut the BS.. Scroll to the end for my questions.

So I'm a newbie and my question is how do you grow MJ?... Just kidding.

Three days ago I knew nothing about growing marijuana. I've been taking aderols (which is intense to a guy who can't drink a coffee without getting the jitters) and reading this forum like it was about to get deleted. I hope the knowledgeable veterans of this forum do not mistake me for a lazy newbie who doesn't do thier homework. My girlfriend just stormed out on me because I didn't get around to having sex with her this weekend. She said "I f**king hope you're marijuana expert" before slamming the door shut and pealing out. All good... we have more important things to discuss.

I've decided that with my goals, funds and space... a hydroponic system is a good fit for me. My reading has given me a good understanding of how they work and of the different types. For newer newbies, here are easy to understand illustrations and descriptions of the different types of hyroponic systems.

http://www.dbcourt.co.uk/hydroponics/System _types.html


Unforetunetly there are no hydroponics shops in my area so I can't see the system in person. I plan on going to the hardware store and build my own but I would still like to see one in action.

Specifically I would like to build a Ebb And Flow - Flood And Drain Hydroponics system. I will use rock wool as my medium in the pots suspended in the tub. Here are my questions...

1. When I flood the plants, how long do I let them sit in the water?

2. When I drain the water from tub that the plants are suspened in, do I send that water back to the reservoir?

3. If the answer to #2 is yes... Won't the plants uptaking nutrients weaken the solution that is in the reservoir?

4. If the answer to #3 is yes... How do I regulate the proper balance of N-P-K and PH in the reservoir? Would I do this by checking the levels daily with a PPM and PH meter and then just adding the proper nutrients to the resevoir until I get a proper reading?

5. How high does the water need to come up on the sides of the pots? Do I need holes in the sides of the pots or just the bottom?

6. How big of a Jackass do I look like?

Thanks

Mr BigBud

I would recommend checking out the five stickies at the top. For Ebb and Flow questions I like this thread, Ask Lucas and recommend it a lot.

1. I think it depends on the medium. I don't use Rockwool so you might want to get another opinion or check the stickies.

2. Yes.



3 and 4. I change the res every two weeks. All nuted up my water starts at ~1300ppm and 5.8 pH (you'll want a ppm meter and pH meter. Bluelab Truncheon is best ppm meter imo, pH meter is debatable). Over the two weeks I top off with plain water as needed to keep the water level constant, maybe a little pH down to get it back down to 5.8. I don't worry about ppm except when I am filling the res, but the pH will creep up allowing the plant to absorb a range of nutes. Adding plain water raises it as well. In the Ask Lucas thread I linked, he talks about adding nutes back instead of plain water, and doesn't change his res as often. I think if you have water with a naturally high ppm it can mess with the stabillity of your pH a little more but not totally sure.

5. I just use standard 8" pots with holes in the bottom

6. Not at all, everyone has questions.

I am currently growing using ebb and flow method.1-Flood 3x's a day 30 min. intervals.2-Yes here is what an ebb and flow kit looks like you need an over flow tube .3-yes you should change you reservoir every 1-2 weeks.3-they have nutrients that are made for hydroponics I use Botanicare line nutrients,water needs to flood about 3/4 of your medium and you need ph up and ph down to regulate ph (ph should be maintained between 5.8-6.3),if your reservoir levels drop due to heat remember it is the water that evaporates not your nutrients so adding plain water only will be fine until next res change,and hole on the bottoms so roots don't get exposed to light.It sounds like you are a novice you should read general hydroponics book before you jump into growing hydroponically not trying to put you down just trying to save you a headache.Good Luck

So i decided to cut the b.s and just now read about your situation funny ass hell,,,,,,,,thats happened to me,females are attention whores,LOL
Oh yeah I use rockwool cubes and hydroton(expanded clay) as medium.

Thanks Dudes

do me a favor, watch seemorebuds dvd 2 and 3, instead of a rockwool based system you may be better suited for clay pellets, what do you guys think? large RW cubes may get over watered, salts build up in it, PH may vary from whats in the RW and the rez, oversatured RW can get oxygen starved....maybe a 1inch RW cube for starters inside a netpot with clay pellets? in the aformentioned flood table....just a couple drawbacks from RW slabs and cubes to recommend for a first time hydro grow

Mr BigBud said:

Unforetunetly there are no hydroponics shops in my area so I can't see the system in person. I plan on going to the hardware store and build my own but I would still like to see one in action.

Click to expand...

Simply Hydro maintains a good comparative reference here.

Specifically I would like to build a Ebb And Flow - Flood And Drain Hydroponics system. I will use rock wool as my medium in the pots suspended in the tub. Here are my questions...

Click to expand...

Good move, flood (aka e&f) systems are cheap and dead-nuts reliable.

Your watering interval depends on how much water your medium of choice will hold. Rockwool is HIGHLY absorbent, so you'll water that rather infrequently, 1x/day in most cases.

1. When I flood the plants, how long do I let them sit in the water?

Click to expand...

If using pots of RW, it's only necessary to raise the water level to the overflow and then shut off the pump. Depends on the size of the tray but usually 3-4 minutes.

2. When I drain the water from tub that the plants are suspened in, do I send that water back to the reservoir?

Click to expand...

Flood systems use centrifugal water pumps. When the pump is powered down, water will flow backward through the pump and into the rez.

3. If the answer to #2 is yes... Won't the plants uptaking nutrients weaken the solution that is in the reservoir?

Click to expand...

Yep, the solution returned to the tank may be a little bit weaker in ppm concentration than the solution you pumped up to them. This is normal. However, along with consuming nutes, the plants will also transpire water.

If your tank is the ideal size for the number of plants it is supplying, the amount of water transpired and thus removed from the nute tank will come close to the relative amount of nutes eaten, meaning the nute tank can remain very close to the same ppm as it was when you mixed it. I find that about 5L of nute tank volume per plant is just about right.

4. If the answer to #3 is yes... How do I regulate the proper balance of N-P-K and PH in the reservoir? Would I do this by checking the levels daily with a PPM and PH meter and then just adding the proper nutrients to the resevoir until I get a proper reading?

Click to expand...

You won't have any way of measuring the N, P & K individually. All your TDS (total dissolved solids/salts) meter can tell you is what the conductivity of the total solution may be.

The correct way to maintain your tanks is to mix to the right ppm and observe the ppm over several days. If the ppm is rising, it means that water is being consumed proportionally faster than the nutes. In that case, you add plain water until the ppm drops to the desired level (1000ppm is a good target). If your ppm drops without the water level dropping much, the tank isn't big enough for the plant count it is supplying. Nutes are being consumed proportionally faster than the water. Get a bigger tank, aim for 5L/plant.

It is NOT a good idea to add more nutrient concentrate to an existing, partially depleted tank of mixed nutes. Plant may consume different proportions of N, P & K at differing rates. You won't have the facilities to measure N, P & K individually so you won't know which need to be topped up. When you mix a new tank of sauce per the maker's instructions, you will have the N, P & K in the proportions marked on the container (i.e. 10:20:10). If you add nute concentrate to a partially depleted tank, the N:K ratio can end up nowhere close to the maker's specification.

Mix a tank, run it for about 2 weeks, dump and clean the tank and then mix up an entirely new tank of fresh sauce.

5. How high does the water need to come up on the sides of the pots? Do I need holes in the sides of the pots or just the bottom?

Click to expand...

With rockwool as a medium, you really need only flood to about 1/4-1/3 the height of the pots. RW has a very strong wicking action and will do the rest for you. RW is VERY easy to overwater, meaning driving all the air out of the medium. Don't be tempted to water RW more than 1x/day unless the weight of the pots drops below 1/4 their wet weight by the time the next watering is scheduled.