System Design Help: Outdoor DWC Vegetable
 

I am ready to build my first DWC garden. I live in Tucson, AZ and am planning a build on the southside of my house which will have pretty full exposure through mid day but pretty good side coverage so as not to have too much sun.

I would like to grow salad greens, hopefully including spinach, Red Peppers, cucumbers, tomatoes and cherry tomatoes. We have 2 people to feed and were hoping for as close to year around production as we can.

I would like to know what the best system design would be. Right now I am thinking about burying several 5 gal buckets in the ground and having a reservoir for the nutrient water. I am new to this so I do not know how many buckets I should use or if that would be the correct size. I think I would like to have 8 options for different plants. I read somewhere that too many single pots with central reservoir would be difficult from a maintenance standpoint.

You feedback is appreciated.

How warm/hot will the water get? Any thoughts to nutrient temperatures?...

since we have such intense sun in arizona I was planning on burying everything. I think the temperatures will be rather controlled

Specifically, i have heard soil temps are around 55 here but since it will partially at surface maybe a bit higher? Would just be guessing

looks like you have experience with this, would you also bury the buckets?

Not that I know a lot about this stuff (just getting started myself), but I gotta believe there is a reason that most commercial nurseries use NFT setups.

Maintaining several different reservoirs will require more work, but it can also provide some insurance should you have a problem with one of them. With several different ones, you can customize your nutrient solution for the specific plant variety (all your tomatoes together, all your lettuce together, etc.).

In Arizona, I'd say you'll need to bury as much stuff as you can (reservoir, pipes, grow containers, etc.)

http://ts3.mm.bing.net/images/thumbn...6e09feb1e85d8e

I live in AZ also and have indeed used the ground to cool the nutrient solution. First, the ground temp wont be that cool. Your looking at about 72 degrees 3 feet deep, and it may be cooler deeper (say 10 feet deep or more) depending on moisture level. Five gallon buckets are only about 18 inches tall. So they wouldn't be more than 16 inches deep (leaving the top 2 inches above ground) unless you build a lip around them to keep the dirt out.

Second your planning to grow both large and small plants, and I don't know how you plan to work that out. Five gallon buckets for large plants like tomatoes and cucumbers is too small for me to consider using, and way to large for lettuce and spinach.

It sounds like your planing to dig 20-30 holes for 5 gal buckets (with planing 8 different plant types). There are three issues I see going that route.

First is each 5 gallon bucket will really only have about 3 gallons of water in it at most. And not being very deep the water temp will wind up too high (especially such a small water volume).

Second is each bucket will need an ample air supply for the roots. This poses two problems. One, the cost of buying one or multiple pumps able to supply enough air to them all. Two, pumping hot air into your buckets will defeat the purpose of trying to bury them in the ground in the first place.

Third is maintenance. Small lettuce plants wont be too much of a problem because their easily removed with the lid, and don't drink nearly as much water as the other plants. The larger plants will drink in excess of 1-2 gallons daily, and with only about 3 gallons of water in each bucket, your going to need to do constant maintenance in both relapsing the used water, as well controlling the fluctuating nutrient concentrations from the constant changing water volume in the buckets. Not to mention how your going to remove the lid and root-ball to clean out the buckets and nutrient changes periodically while the plants are growing.

I would say your much better off going a different route, using a flood and drain, and/or drip system/s. Using large reservoirs at least 3 feet deep. insulating any part of the system above ground.

P.S.
Lettuce will just bolt in air temps above 85-90 degrees (even under shade cloth). That is elongate and produce seed pods. You'll be better off trying to do lettuce indoors in the air conditioning and under florescent lights during summer in Arizona. Then a simple water culture system would work fine. But I still wouldn't use five gallon buckets for lettuce. Their just the wrong configuration (shape) to maximize space and yield.

I agree, lettuce will do much better inside in a bubbler system using additional lights if you dont have a window near by. You can either drill holes in the lid of a tote or drill holes in a sheet of styrofoam and float the lettuce, both work great. All this type of system will require is an aquarium air pump and some air stones.
My temp's got into the high 90's and low 100's last summer and 2 of my three systems did great with it. The outside bubbler got too hot even with a homemade chiller to cool the nutes. The NFT continous flow system did good and would have done better if I buried the nutes. I just added frozen 2 liter bottles when it got that hot. The system that did the best was the 1/2 55 gallon barrels with pea gravel on a flood and drain system. Again i should have buried the nutes, but I was learning as I was going and the frozen 2 liters did the job as well as increasing the time and intervels of flow till fair week. Someday I will have my greenhouse with some climate control.....