Originally Posted by W33DM4N420

Hey guys I finally got my DWC setup all complete and just waiting on a 400 Watt HPS in the mail. I'm just using a 10 gallon tote with 4 net pots and using rockwool to start the seedlings and Hydroton as a medium. I have a few questions...

1. What is a good water temperature for my reservoir?
As cool as possible, 70 degrees or below. Mine are at 66 degrees.

2. How long before I should start adding nutrients to my reservoir?
Start as soon as you put the plants in DWC. A quarter-strength solution to start.

3. How often should I change out the water completely in the reservoir?
I've never frown DWC, but my understanding is that you top off your reservoir daily, keeping PPM the same, but once you add back 10 gallons of water, it is time to change your res.

4. Do I keep feeding my plants nutrients up until the day of harvest?
No. You want to flush the nutrients out of the system. The way I'd do it is to stop adding nutrients to your DWC 2 weeks before harvest and only top off with pH'd water. Diluting the nutes keeps your plants from starving, but will begin to eliminate the nutes.

5. I am buying the General Hydroponics Flora Series nutrients.(Micro, Grow, Bloom) Do I start with the micro?
You use all three nutrients at once, all the time. The amounts will change with the age of the plant. Full strength veg formula is 3 tsp Grow, 2 tsp Micro & 1 tsp Bloom. I start seedlings at one quarter strength and go up from there. Transition (the first two weeks of 12/12) the formula is 3-3-3 and then it is 1-2-3 for flowering. Some people also use the Lucas formula which eliminates the use of Grow all together. In veg it is 5 ml Micro & 10 ml Bloom per gallon. In flowering it is 8ml Micro & 16 ml Bloom per gallon. I have used this formula in flowering only and have found it to be too strong for some plants.

6. If I start with the Micro, when do I start it and when do I switch to the Grow?
See above.


7. This may be dumb but when I switch nutrients, Do I have to empty my reservoir and start with a new batch of water?
I do to ensure my plants have nothing but fresh nutes. One doesn't know which ones are taken up at what rates, so I like to be sure they are all there.

Please try to answer these as specific as possible. Thanks!

Originally Posted by W33DM4N420

Okay thanks for the reply but lol I knew I would think of more questions....

1. Do I ever need to replace or change the hydroton?


No you do not need to. I'm a hempy guy but from reading grow journals, you never need to replace it. Once you purchase it, the only thing left is to rinse it so the dust is removed because that can alter the PH. Someone correct me if i'm wrong? The dust goes into the resevoir, thus increasing Parts per million or it acts as a buffer?

2. I guess I am still a little nervous on the nutrient thing. Is it okay to just follow the instuctions on the bottle?

Well ya you can. On the back of the GH grow, micro, bloom bottles, they have a little chart stating their recommendations:
1.Cuttings/seedlings= 1/4tsp per gallon for each part.
2.Mild=1tsp per gallon of each part
3.Vegatative growth phase=3 tsp/gal grow-2tsp/gal micro-1tsp/gallon bloom****
4.Transition= 2tsp per gallon for each part
5.bloom/ripening= 1tsp/gal grow-2tsp/gal micro=3tsp/gal bloom****

Some people use this formula and have no problems what so ever, mainly in part due to their strain. Others will burn the shit out of the plants using these formula's, especially the ones i labeled with the astericks.

Now I will convert each formula to a TDS(parts per million) @.7 and @.5 reading on my nutrient profile excel sheet so you can view these numerically as follows:
(note- keep in mind the TDS readings are soley based on the nutrients. They do not take into account your starting tap water. Basically, what i'm doing assumes you are using Reverse osmosis water with a starting PPM of about 0-50)

1. 228 ppm @.7 and 163 ppm @.5
2. 910 @.7 and 650 @.5
3. 1896 @.7 and 1354 @.5
4. 1820 @.7 and 1300 @.5
5. 1896@.7 and 1354@.5

So you can see how these figures may be WAY high for strains such as white widow. The best advice i can give you is to read daily PPM and PH fluctuations. Read it in the morning and night.

Old Pharts cheat sheet explicitly states: PH goes up, PPM goes down the plants want more nutrients. PH goes down, PPM goes up the plants want less nutrients because the mixture is too acidic. When you find the spot where PH is fairly stable and PPM doesn't fluctuate up or down more than .2 EC or 140 PPM @.7 in 24 hours then your right on the money and have your setup dialed in. If you aren't using monitoring devices then just watch your plants because Hydroponics will show you symptoms in a short period of time.

3. How long can a plant(seedling)live without nutrients? (Plain water) <----Reason I ask is because this is where I get confused because when the seedling is in the rockwool, the roots won't be coming out to where I can stick them in my DWC where they can be in the nutrient solution. Would I have to mix up nutrients in like a gallon jug and just hand feed the seedlings until the roots are long enough to be submerged(splashed)in the nutrient solution?



From my research, a seedling doens't need nutrients until its first true leaves, aka cotyledon, turns yellow. The cotyledon is the seedling's foundation or powerhouse from the time it cracks the shell only until a certain period of time. Once the first set of leaves turns yellow, that indicates the seedling has used up all the 'juice' in the leaves and will need more to ensure survival. So wait until that happens or you can give it a week dosage of nutrients like 1 ml/gallon of each part and watch for any bad signs.

In your case, since you are growing via DWC, you are going to need some roots to be through the net pot in order for it to come in contact with the solution. What i recommend is keeping the rockwool in a tray and hand feeding it until you can see visible roots coming out underneath the bottom. Once that point comes, then you are ready to transplant into the netpot/hydroton. Keep the water level, i believe, an inch underneath the net pot? Someone correct me if i'm wrong. At this point, you'll now have roots and they'll be able to reach the resevoir and explode! I

Sorry if these questions seem to dumb, but I have been reading and researching for a while now before I jumped right into this. Just wanna make sure I am doing things right.

Originally Posted by yingyangsoup

Sorry for the lengthy response.

Originally Posted by bluecheese

yingyangsoup you are correct - I was wrong. It is 1-1-1 for transition. I slipped into ml - sorry.