Recirculation: the key to better yields?
|Quickie recirculation system
One of those techniques I ran across by accident was using constant recirculation of nutrients. Most auto-feed techniques wind up using wicking to get the liquid food up to the roots. Thats how Autopots, Octopots and most duoponic systems work. As it happens, I was in the process of re-engineering a standard 5-bucket Deep Water Culture hydro system (4 buckets for plants and a 5th for a reservoir plus a way to test/correct the pH, food, etc w/o screwing with the plants to get at the fluids). I was experimenting soil/hydro hybrid systems and one of the ...not exactly problems but faults in design with the wicking systems is the lower roots get some food/water first and depending on your medium (I was using hydroton) there is uneven wicking of the water and the root systems don't always get all the food they could be using.
Now I already had all buckets hooked together via garden hose (hey I experimented with everything). Before this was the feed for the DWC system; now it could be a "return". I figured to give the root system a jump-start by sticking a pond pump into the rez bucket, then use a 1 foot bit of garden hose to get the pumped water up and out the top, where it was split into 4, 1/2 inch feeds for standard irrigation hose. See below:
|The basic reservoir with pond pump to 4 feed lines. Bottom of bucket has a 3/4 return line.
So the way I rigged this up was I filled the rez, the pond pump constantly pushed many gallons per hour of nutrients down four feed lines. Each want to one of more plants sitting in buckets connected to the rez by the return lines. I was also working on ways to keep things flexible, so I tried this out using a standard 6-inch netpot in the top of a bucket (a la classic DWC) and in the bucket next to it, I put a baby crib riser in the bottom of the bucket, then set a 2-gallon grow bag with plant on top of that and stuck the feed line into the top of that. In the case of the netpot, I just stuck the feed line into the hydroton near the plant roots. The nutrients where pumped over the roots 24 hours a day; the fluid would drain out of the grow medium and collect in the bottom of the bucket, where it followed the return-line back to the main rez where it was filtered and it started the cycle all over again.
Here are a few shots of it in action:
|Trying this in as many ways as I could think of
|Using organic soil and a grow bag
|Shows the recirc system in with the rest of veg
The Bottom Line:
Why do all this? Well as it turns out, any plant grown under these conditions seems to veg and grow at an amazing rate. It didn't seem to matter what I stuck into it, clone, seedling, regardless of medium or method used and bam, they just grew many times better than any other method I have tried before or since.
I didn't keep up with it because as it was then built, it presented to many problems to my future design of my grow system. It wasn't portable to bloom (which was either pure hydro or pure soil), plus one of my major design guidelines at the time was to make each plant as portable as possible, meaning I wanted to put put the clone or seedling in some special kind of pot, do all the vegging I needed (which this worked with well), then just pick up the container with the plant and drop it into something in bloom and presto, it gets bloom feed, it. I got there but was not able to make the recirc system work in the mean time. The other day I was discussing this with my grow mentor and he agreed it did the best work and wondered why I didn't use it with my current system....So two days ago found me fooling with pumps, timers, drippers and so on. I had 4 new (and therefore tender, young and weak) White Widow autoflowers that had just sprouted in my DWC rig that I had transplanted to my To Go Cups with hydroton and they have been vegging in one of my tubs with veg nutrients...
So I hooked an 80 gallon-per-hour aquarium pump to some 1/4 inch irrigation tube. This tube was then run past my four plants in the tub. Where each plant was, I snipped the main feed line, added a T connector, then a short 3 inch bit of tube that went to a standard drip emitter. In this case the nutrients are constantly washing over the root system before rejoining the rest of the nutrients in the tub.
And just like before, I had this hooked up less than 12 hours before the four thin and tiny sprouts were suddenly perking WAY up and showing vitality they had not shown to date.
So look into adding some form of recirculation to your grow setup. You can do it for less than the cost of a single bottle of those fancy bloom nutrients and I would argue this ends up improving the plant and hence your yield more that the fancy add-ins do.
As much as is practical, I will be designing this into every system I do from now on....