passive plant killer

[LJB]

more congratulations to delta. You are mastering and helping others with one of the topics, i.e. the perched water table, that along with lighting (i.e. watts/lumens/human eye vs photons / daily light integral) are the least understood by container gardeners

How do we know?

Any search on the internet for information on the subject invariably and very quickly, leads one back to this thread.

 

[LJB]

this person had a few ideas:

http://www.seattleoil.com/Flyers/Earthbox.pdf

 

[delta9nxs]

thank you!

thank you!

Thanks, everybody!

I'm just glad it worked. This is the first plant grown in an untried device. I thought it would work, but you don't know until you try.

I held this one to no runoff, no top water, and no ph adjusters really just to see if I could do it. Although I grew a decent plant it is still not up to my normal yield with this strain. usually around 10 oz.

Now that I have grown one this way I can say that it required a lot more monitoring to keep tds and ph in line keeping true to these parameters. (no run off, no top watering, no res changes)

I controlled both by varying concentration strength. The flora nova bloom is very ph stable to start with. 900 ppm on a .5 meter or ec 1.8 ph's to 5.8 or so but quickly rises to 6.2-6.5 and then just stays there. This is in ro water.

There is usually an inverse relationship between ph and tds. The higher the tds the lower the ph, so when the tds would get up to around 1250 or ec 2.5 the ph would be lower, say around 5.4-5.6, which is fine for ph but I don't want tds to get over this reading so I would input solution around 750 ppm or ec 1.5 with a ph of around 6-6.2. this would bring the tds down to around 1000 ppm and bring ph up to at least 6.

if the ph were too high, say over 6.6 I would input a stronger solution of 900-950 ppm at a ph of 5.8. this would usually bring ph back down to 6.2-6.3.

now that this first plant is out i'm relieving myself of all constraints regarding overflow, ph controls, or top watering. I have already been doing this with the other plants. Some of them are really putting on some size. Linking the containers and auto topping should radically reduce my work load and even out differences in tds and ph.

As I described earlier in this thread I have numerous media experiments going on and haven't really decided what I like the best. It will take a few more months.

All the plants are looking good with no deficiencies showing, regardless of medium.

Apparently, 100% coco likes the flora nova bloom with the cal-nit and the epsom. I'm growing a thick, healthy looking plant in it. No deficiencies.

From turbolaser:
“anyway, I was wondering if you were to simplify this method for a grower new to passive hydro, what basics would you leave them with?
if running coco/perlite mix or straight coco using the media as the wick, do you just keep the bottom 1" or so of said media in contact with the res/water? I still don't get that part, and assumed that the wick pulled water up, without it how does the plant get it through the hole in the bottom of the 5 gal?
this is why im guessing the roots have to contact the water obviously, but what are the parameters needed to ensure a healthy plant and bountiful harvest? Thnx”


using this type of device the air gap between the res and the bottom of the growing container is critical. It moves the pwt further down in the container. And maintain the res as high as possible without eliminating the air gap. This gets a better wetting profile. Also, make sure, before you put a plant in it, that water flows right through, unrestricted.

In this first plant I had no roots come through into the res. Which kind of surprised me as I expected some. You don't really need the roots to contact the nutrient solution in the res. The medium is wicking enough moisture upwards to feed the plant.

By limiting the volume of water type roots that form and keeping solid water out of the growing chamber by moving the pwt down you promote the growth of more air type roots.

You definitely don't want any standing water in the root zone. The roots that may grow down into the res will be water type roots similar to dwc or bio-bucket roots and as long as the total plant is getting enough o2 overall these roots do not have to be aerated.

Hey ljb, the earthbox is one I looked at before I started building. There are at least 30 different approaches to solving the pwt problem. I stole ideas from all of them. Hehehe!

Here is another one.

http://earthtainer.tomatofest.com/pdfs/EarthTainer-Construction-Guide.pdf

the internet is full of various attempts to control the pwt. 20 yr old patents for molded plastic pot configurations that try to reduce the pwt. They use a variety of shapes and convolutions in the pot design. I'll try to post some of the more interesting ones.

This is the 100% coco plant. It started very slowly and I thought initially I was going to have problems, but it has started growing aggressively and looks great. It has had the first series of pruning cuts made to it and has been topped. It's at the end of week two of veg. I have had two very experienced coco growers tell me this is not going to work.

 

[delta9nxs]

well, that pic didn't work out. 8 inches from a 1k hortilux. i took the plant out of the room for these.

 

[jump /injack]

"Not bottom feeding per se, as ebb and flow is bottom feeding yet retains a perched water table every time it's flooded. A perched water table that can only be eliminated by evaporation or transpiration."

delta9nxs, great thread, have been following along. It was explained somewhere but I can't find it now, what is a "perched" water table??
I've looked in 2 dictionaries and can't find out what it means, must be a horticultural term and I don't have that type of dictionary. Hope you draw up some plans to peruse, would be very choice information indeed.

 

[delta9nxs]

hey jump /injack, welcome aboard! thank you!

 

[turbolaser4528]

thnx for the info, im going to do some more research on trying to make the medium the wick and keeping the water level (float valve right?) even.

 

[delta9nxs]

hey, turbolaser!

i've got 2 pure coco, 2 40/40/20 perlite/turface/coco, and 3 90/10 turface/coco going now without the cloth wicks and they all seem to be working.

my version shows a standpipe controlling water level but a simple overflow hole works fine too.

i intend to use a float valve on a control bucket that is linked to all containers so i can control the water level in all of them simultaneously.

i've got a set of pics now showing exactly how i built mine with construction details if anyone is interested.

later on, d9

 

[fishinnutt]

I am interested in your build design plans.

 

[jump /injack]

Would like to see them very much. Between you and Mistress there has been some very interesting designs and models, many Kudos. Very fine writing and research, the auto watering would be the polish on the apple, a complete system in its self with no moving parts unless you wanted air in the tank.

 

[delta9nxs]

ok, you asked for it! i hope this doesn't bore everyone to tears.

they're in sets of 4. i'll comment or answer questions as i go.


that's a 1/8" bit for the pilot hole, or whatever you got.

 

[delta9nxs]

that's a 1 7/8" hole saw. fits 1 1/2" fittings.

the sharpie holder with the pin in it is 7.5" on centers, making a 15" circle.

 

[delta9nxs]

duh!

 

[delta9nxs]

the white fitting is a 1 1/2" male plumbing adapter that's been cut off to make it more flush with the bottom of the bucket. i've used a grinder, a hacksaw, and a miter saw at different times to make these. a power cut off saw is ideal. plywood blade.

the gray fitting is a 1 1/2" female electrical adapter. if you use it with the white male adapter the threads reach through the materials better. goes on much easier.

 

[delta9nxs]

1 1/2" tubing

 

[delta9nxs]

the 1 1/2" x 5" tube will extend to within one inch of the bottom of the reservoir.

the square is set at 7 1/2"

the spade bit is 3/8"

 

[delta9nxs]

small bit is 1/4". necessary to let air breath as res level rises and falls.

spade bit is 13/16" or whatever just to aid circulation.

 

[delta9nxs]

views

 

[delta9nxs]

tubing and fittings are 3/4". spade bit is 15/16".

 

[delta9nxs]

important to drill this hole right at the point where the radius starts.

fat 3/4" o ring on 3/4" male electrical adapter. you must use electrical fittings for this as they have machine threads and will create a waterproof seal.

put a little teflon tape on the threads for further waterproofing.