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Anyone have experience with NFT?

theghostpepperstore

theghostpepperstore

Due to some really inconsistent weather this year, our field grown lettuce was less than predictable so I made the investment into a 8-channel, 144 spot NFT system, a 4' x 8' x 7" flood table and a 4' x 4' x 7" flood table. The hope is to supplement our weekly farmer's market sales with 36 heads of lettuce each week.

The NFT setup is using a underground reservoir, which I thought would help with both algae growth and keeping the water temperatures down. I have a 1000gph pump which, surprisingly, is only getting me about 7L/m return at the drain pipe. Each channel is fed using (2) 1/4" microtube with an inline adjustable flow valve.

I will be using the smaller flood table to start my lettuce/spinach seedlings in 1.5" rockwool cubes then transfer them to the NFT once the roots are coming through the bottom. This tray will also double as a starting area for some of the other veggies in the Spring since it is quite an overkill since I will only be starting about 20 lettuce seeds each week.
 

Untitled by GhostPepperStore.com, on Flickr
 

Untitled by GhostPepperStore.com, on Flickr

I also have a 1000w MH light mounted centrally to provide supplemental light during the shorter days, I plan to keep it to about 14 hours/day. The greenhouse is heated and I keep night temperatures at around 62 degrees. Daytime temperatures, except in the Summer, stay below 85. I have invested in a pH meter and EC/TDS meter but at the moment I will be using tap water which is testing at 7.5 pH and 250ppm. I do not plan to change to RO water unless absolutely necessary.
 
(Those are 4 types of Rocotos, some hybrid Chinenses, and cumaris in those trays besides the rockwool)

Untitled by GhostPepperStore.com, on Flickr
 

So now for the questions.

This is my first time using rockwool. I sowed 8 varieties of lettuce, spinach and some herbs in the cubes on Sunday after soaking the rockwool in a 5.5pH bath. This morning, the cubes are still very wet. Is this normal? I realize the seedlings are not using any of the water yet, but since I will be giving these the flood and drain treatment, it concerns me that the cubes are staying wet for so long. The cubes are not covered since I have decent humidity in the greenhouse this time of year and it has been raining for the last couple of days to boot.

I know that for most NFT systems the recommended flow rate is 1L/minute per channel. I am not quite getting that rate at the moment, is this going to be an issue?

I am totally open to constructive criticism here, so please, if you see something wrong with my techniques, call it out.
 
 (4x8 table with some stragglers that needed a couple of weeks to ripen remaining pods)

Untitled by GhostPepperStore.com, on Flickr
 
(Just for the heck of it, wilds gone wild, Chacoense, CGN 19198, Praetermissium, Parviflorum, Galapagoense and Flexuosum)

Untitled by GhostPepperStore.com, on Flickr
 
PepperLover said:
very nice set up 
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I appreciate the the response and thanks for the "like", but I am actually looking for input here.... this is the number #1 reason that this forum is about to be officially dead to me.
 
Very Nice!! I seen them setup on Youtube and they look great!! I just getting my lettuce growing but they will be in a smart pot in my little greenhouse!
 
I would say that the rock wool is staying wet because nothing is using the water and it being cooler it's not evaporating as quickly
 
Nightshade said:
I would say that the rock wool is staying wet because nothing is using the water and it being cooler it's not evaporating as quickly
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Thanks, like I said, I have read rockwool holds a lot of water but 5 days and they still seem to be soaked has me a bit concerned. Every seed I put in the cubes has germinated, so I can't complain. Hopefully they will be ready to hit the NFT channels next weekend. As long as I have the process hammered out by next May, I should be OK.
 
 
Nightshade said:
You have sprouts on your flexousums Very nice
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Thanks, I was lucky to get two sprouts and I was very surprised that the Galapagoenses had 100% germination. The only wild that has skunked me so far has been CGN 20497. I have at least two of every other variety.
 
theghostpepperstore said:
 
I appreciate the the response and thanks for the "like", but I am actually looking for input here.... this is the number #1 reason that this forum is about to be officially dead to me.
Click to expand...
 
Wow
 
By looking at the pics of your greenhouse it is very humid in there so it's going to harder for the air to hold anymore water. Man that is lucky if you don't mind me asking where did you get your flexousum seeds?
My suggestion on the humidity would to open the door/vents and turn on a fan during the hottest part of the day to circle out the humid air
 
Nightshade said:
By looking at the pics of your greenhouse it is very humid in there so it's going to harder for the air to hold anymore water. Man that is lucky if you don't mind me asking where did you get your flexousum seeds?
Click to expand...
 
It is actually not as humid as it looks in the picture. It was 26 degrees outside this morning when I took these pictures so there was probably some condensation on the camera lens.
 
I believe my Flexousum seed came from Chris Phillips.
 
are the tops of the nft trays open? seems like too much light would get in that way and you'll be fighting alge/mold. Look to enclose them and only have an opening for the plants.
 
Also, are you using the flood table for plants in soil? While I guess it would work, soid probably doesn't drain fast enough and you could end up with root rot.

I have some notes on my issues with a flood table in my glog. I just updated it with more info. Check it out.

Never used rockwool, but the hydro shop by my office sells a ton of it so it must work.
 
Jeff H said:
are the tops of the nft trays open? seems like too much light would get in that way and you'll be fighting alge/mold. Look to enclose them and only have an opening for the plants.
 
Also, are you using the flood table for plants in soil? While I guess it would work, soid probably doesn't drain fast enough and you could end up with root rot.

I have some notes on my issues with a flood table in my glog. I just updated it with more info. Check it out.

Never used rockwool, but the hydro shop by my office sells a ton of it so it must work.
Click to expand...
 
I do have lids for the NFT channels. They have 1.375" holes on 8" centers, I am using 1.5" rockwool so the plugs will fit snugly and keep almost all the light out of the trays.
 
The 4x8 flood tray will be used solely for bottom watering pepper plant starts. They will be the an amended soil-less mix that I use, but they won't be grown "hydroponically". This is designed to just cut down on the amount of time it takes me to bottom water all my pepper starts (once every few days). I can do 16 trays at a time this way instead of doing 2 at a time like I did last year.
 
I will check out your glog and see what I can learn. Thanks!
 
Sounds like you have a solid plan. Keep us updated with your progress.

I've been told hydro lettuce takes about a month to grow but I have no direct experience.
 
If you don't get your answers here try heading on over to reddits subreddit r/hydro. There's some guys that work with smaller ntf systems in there and could possibly help out better than here man.
 
xxkamikazexx said:
If you don't get your answers here try heading on over to reddits subreddit r/hydro. There's some guys that work with smaller ntf systems in there and could possibly help out better than here man.
Click to expand...
 
THANKS! I hadn't even considered reddit :doh: I had posted in a couple of other forums earlier this week but I haven't gotten any responses. I will have to find my tin foil hat before I venture into the depths of reddit, but I really appreciate the tip.
 
Wow nice setup! I am rather new to hydro myself, so I cant tell you much other than rockwool retaining moisture that long is completely normal. When you say you're using tap water at 7.5 ph, you mean you are ph adjusting it before you use it, right? 7.5 is awfully high
 
illWill said:
Wow nice setup! I am rather new to hydro myself, so I cant tell you much other than rockwool retaining moisture that long is completely normal. When you say you're using tap water at 7.5 ph, you mean you are ph adjusting it before you use it, right? 7.5 is awfully high
Click to expand...
 
Good catch, yes I will be adjusting the reservoirs to 6.0 pH. Thanks for the input though, it makes me feel better knowing that the rockwool issue is normal.
 
Yeah, rockwool really sucks the water up. When planting seeds in it for the first time I was afraid they might rot or dampen off. No problems yet though...
 
I've found that because rockwool holds so much water, roots are slower to stretch out looking for it, so they stay contained within the cubes longer.
 
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