You may have difficulty tending the plants in the middle. If the frame was about four feet wide you could reach the center easier.

Good luck with your project !

I was thinking the same thing, I made the rails where they can slide the length of the frame either way. So I can pull the water tube in this case a 1/4 in line, drain the rail then pull it completely off of the table if need be. Think that will suffice?

I am shooting for a production system that will harvest up to 86 heads of lettuce a week. Thanks for the comment. I am trying to work the bugs out as I go!

Yes, I suppose you could do that, but if the rail is full of plants it may be a little awkward to handle.

you could create an aisle down the middle of (perpendicular to) your 2x's to make access easier. However, without water in them, they won't be particularly heavy.
I would suggest you cover them with aluminum foil. those downspouts(DS) will still let a lot of light through. It only takes about 2 minutes per tube to cover them. pull out a 10 ft length and lay flat. spray the bottom side of the DS with spray adhesive. place the DS top down on the aluminum foil then wrap the foil to contact the bottom of the DS. another quick spray of adhesive sticks the other side down and you're done.

I can do that. Would that help reflect heat too? I am not going to be able to bury the resovour where this is going to sit. This is a trial run, if it works out toprove the concept we will put it into the greenhouse for the winter and make it part of our operation.

I would like to get to the point that the bulk of our salad crops are grown hydroponicly.

Yes it will help reduce heat gain also.

Worth it for that if nothing else.

Well it is up and running! Had some trouble getting the nutrients right today. Started out around 1040 ppm, the directions called for 29g per 5gallon, I did it that way but had to add an extra 5 gallon to the original 10 to get the ppm down to 850. I have about 30 starts in the system now. If they are not all dead tomorrow I will add the rest.

Otherwise it runs great,

I do have one question, how thin do they mean by thin film technique? It is just covering the bottom of the gutter. I added some hydro ton in the ends of the tubes to back the water up slightly but it just washed on out.

In those downspouts you'll normally only have a layer about 1/8" or so thick. eventually the roots will get large and you'll need to increase the slope of the troughs so the water will push past the mass of roots.
I assume at that point there is some minor ponding behind the root mass.

Rio
could you post pictures of where / how the water enters and exits the troughs?

I added a 1/4 inch dam to the drain end tonight. I had some net pots I bought on the Internet that were 1/4 inch shorter than the 250 we ordered. I didn't realize till I got them in the system once I rotate those through I will pull the dams out.
Will it hurt the ones who are sitting in a 3/8 in water stream?
I will get you some pix.

I know you can't see much here but there are 2 1/4 inch feed lines in each down spout. That dumps into a notched out 3 inch pipe that 90's for the water to dump into the tank. There is about 2 foot drop into the tank and I have aeration. I plan to bush down to 2 inches and dump in with a 2 inch pipe. Just so I can close it up some to keep light and rain out.

The photo makes it look a little hibilly and. It may be. My shade cloth hasnt arrived yet so I pulled the side up on the shade house and just have it propped.

The rockwool seems really wet. Will it absorb too much being set at the 3/8 ish depth?

Forgot the pix

I expect if you leave the rockwool touching water, they'll always stay too wet.
The 2ft drop into the tank should provide plenty of aeration. I doubt anymore will be required.
so you've cut a 4" wide (or so) square out of the top of a 3" pipe and the ends of the troughs just dump into that?
Are the feeder ends of your troughs "capped"? If so, how did you do it and is it waterproof?

I am new to this so O am bound to make dumb mistakes, but I thought the rock wool had to be in contact with the water?
I had the ph go up signifigantly. the only thing it did was sit over night and I added some hydroton into the system, then removed it.

Yes, I notched the pipe so that the 2 inch tall downspout sits in the notch level with the top. I plan to cover the ends with something to keep the light out. Between the next plantings I will cover everything with foil to keep light transmittance down.

The ends were heated with a heat gun and folded up and in like a package. That seals the end. I poke the feed tubes in between the flap and top. I hadn't read about a method of sealing that wasn't problematic, so I gave this a shot. It doesn't leak that I can see.

I am new to this so O am bound to make dumb mistakes, but I thought the rock wool had to be in contact with the water?
I had the ph go up signifigantly. the only thing it did was sit over night and I added some hydroton into the system, then removed it.

Yes, I notched the pipe so that the 2 inch tall downspout sits in the notch level with the top. I plan to cover the ends with something to keep the light out. Between the next plantings I will cover everything with foil to keep light transmittance down.

The ends were heated with a heat gun and folded up and in like a package. That seals the end. I poke the feed tubes in between the flap and top. I hadn't read about a method of sealing that wasn't problematic, so I gave this a shot. It doesn't leak that I can see.

Ah, that is a novel method. I just quit trying to seal mine. if the slope is great enough the water won't back up an leak out the high end. That was my solution. then I just cap it with a scrap of aluminum foil. That keeps the light AND the mosquitoes out.
I made an elbow in the low end of mine and they dump directly back into the rez. but I like your notch idea. would make for a cleaner layout. just cover the notched area with some of the aluminum foil you have left over.

That's the plan, I wanted them to lock in, but be moveable. The notch takes care of that.

I was a machinist apprentice for a few years and that makes me a bit obsessive with this fitting into that often to my detriment.