View Full Version : Growth rates with different hydro systems?

06-07-2006, 10:15 AM
My little hydro experiment this year continues to aamaze me - the growth rate is so impressive. I would like to build more hydro systems and am wondering which produce the best growth rates.

I'm using a simple tub with a couple bubblers (6 inch strips used for aquariums) and change the water out every 2-3 weeks. In this system all the roots have access to nutrients all the time.

The drip systems seem to be less efficient because they only get nutrients to some of the roots some of the time and the ebb-flow systems get nutrients to all the roots but not all the time. The mist systems are more elaborate and expensive and I wonder if they do any better than the simple system I'm using.

So...I'm asking what people's experience has been and if there is any research on this?


bonneau pepper farm
06-12-2006, 01:54 PM
Well, i have built dwc, aero, nft, and drip units...Imho, the drip is most effective...

nft is easy does a great job and is plant specific...i.e., lettuce and herbs and smaller shrubbery type plants do best in nft.

you already have experienced DWC, so I will omit comments on that.

Aero is best used for rooting...It does well with plants, but doesn't hold up to the growth rate of drip.

drip can be on running all the time during veg (if you are recirculating)...and does cover the roots well, allowing necessary oxygen to reach the roots as well.

If you just want to add a drain and drip lines to your tubs...

take tub...add common household plastic drain, you can by in-expensive common pvc drain parts for it, at any hardware store,
make a small manifold for drips lines I use 1" pvc parts for my manifolds, and adapt 1/4" lines to them...make a sturdy table or shelf for tub allowing enough room underneath for another tub...I use 10g tubs for plants and 18g tubs for nutrient solution...position 18g rez tub underneath drain from 10g plant tub...
use a submersible 90gph-110gph powerhead and attach that to standard 1/2" irrigation tubing...the tubing fits right over powerhead outlet. Snug. (You can adapt 1/2" irrigation tubing to 1" pvc, rather easily.

I drip 60 minutes on/15 minutes off during day photoperiod, and 15 on/60 minutes off during nighttime photoperiod. This works great for most larger plants like tomato's, peppers and cucmbers. imho


p.s. keep in mind on/off times vary according to your set-up, plants and nutrient recipe...It's up to you! peace

bonneau pepper farm
06-12-2006, 05:03 PM
by the way...I have piks thamophis

David G.
06-13-2006, 02:35 PM
Deep water culture is certainly a viable growing method, but it can have its disadvantages. The main problem growers experience is lack of oxygen. Because the roots are almost totally submerged, you need a lot of agitation in the nutrient solution to ensure the plants are getting enough of it. A lack of oxygen may not be immediate apparent, but can lead to slower growth rates as the plants get larger and bacteria problems as well. Due to the lack of growing medium, most beneficial bacteria won't be able to survive to combat the bad bacteria.

Generally speaking, my favorite method is the drip system using coco as the growing medium. Drip irrigation irrigates the medium from the top, and gravity causes the solution to flow through the medium and drain out the bottom of the container. After an irrigation cycle, the growing medium is left with an almost perfect balance of oxygen, moisture and nutrients. Over the next few hours, the H2O starts to dissapear (due to evaporation and transpiration from the plant), leaving a higher concentration of nutrient in the growing medium (as well as a higher amount of oxygen as water is replaced by air). While ebb & flow systems water from the bottom, thereby pushing the accumulated nutrient salts into the top portion of the growing medium, a drip system waters from the top, effectively leaching the growing medium and flushing much of the salts out. In an ebb & flow system, the top portion of the growing medium may become toxic because of all of the accumulated nutrient salts, and the roots may not grow into this area. So, if you though you barely had enough growing medium in that 4x4x4" block, you may be surprised to learn that your plant may only be utilizing 3 of those 4 inches. Another added benefit to drip systems is that the reservoir can be much smaller, meaning you will save money on your nutrient and enhancer bill. In an ebb & flow system, you need a reservoir that is large enough to fill the entire top tray with solution. With a drip system, right after your water pump turns on, the nutrient solution quickly trickles through your growing medium and back into your reservoir.

I like the coco growing medium for several reasons, such as:
1. It's organic and environmentally friendly
2. It provides the perfect home for beneficial bacteria to flourish; in fact, some high quality coco brands already contain naturally occuring beneficial bacteria, such as trichoderma.
3. Coco allows nutrients to be more available to the plants root system than most other mediums
4. Has an excellent air-to-water ratio; if you purchase a good quality brand of coco, you shouldn't even have to cut it with perlite
5. It can be reused (under certain conditions)
6. It's easy to dispose of; you can use it as an ammendment by mixing it into soil in your backyard, etc.
I could go on and on about coco, but I'll finish by simply saying that roots absolutely love coco.

This is not to say that other growing mediums and growing systems don't work great - every medium and system has its application and its pros and cons - I just like dripping into coco because I have found that the success rate among growers (both new and experienced) is consistantly higher with this system, and the growth rate and yield can be exceptional. It's no wonder that the most widely used method of commercial hydroponic vegetable production is the drip method, and that coco is quickly replacing rockwool as the medium of choice among these growers.

bonneau pepper farm
06-13-2006, 05:00 PM
Great post D.G...One of my favorite things to tell folks trying to decide about a system, is about the fact that commercial growers generally use drip; As you stated above. If I might add. Most commercial hydro farmers use drip to waste. Drip to waste gives you more control, overcoming toxic salt problems because each time drip is on, it is fresh ph'd solution, thereby leaching away, accumulated salts that could lead to toxidity. Imho

Unfortunately, this is not cost effective for the average home based hydro operation. later, Roger

I am sure glad you good folks @bghydro, got this forum, up and running. peace

10-07-2006, 01:30 PM
I really have just a little to add about a drip system [using cocopeat, hydroton mixed] ;

(without knowing how big of a system you are building)
If something should happen to the electric or water or who knows what could go wrong at what time the drip system is more forgiving.

With an areo try missing a day or even a few hours the plants lay right down.
[At least that has been my experience]

Of course it matters on what type of plants you are growing.
If its flowers then drip is more forgiving.

Good luck, I wish you the best.