My experience with drip irrigation like you are talking about is remote--I toured a setup in Arizona a number of years ago, and my next door neighbor converted his irrigation system to drip a couple years ago, which he kindly let me help with on occasion. So, take my comments as being from more of an observer. The drip systems are pretty much entirely plastic. There may be some metal, but it isn't common. These systems are rated for a useful life of 15-20 years, so the corrosion resistance of the plastic would give it an advantage over metal. I have been doing some surface drip on some trees for probably 7 years now with a used drip system. Each zone is controlled with a plastic ball valve and I have had no problems with these valves. The T tape that I have seen is buried from 8 to 16 inches deep as you don't want to water the surface of the soil except for germination. After that, you want to keep the surface dry to help control weed germination. In addition, the tape is buried deep enough that it won't be damaged by plowing or other field operations, and being deeper helps to hide it from moles and gophers which love to chew on the tape. If you do put it shallower, you could probably pick it up in the fall and store it inside when used on a small area such as a garden. I wouldn't think it would move in the soil, although if the lines get moved or kinked, when they get pressurized they will straighten out. I have also seen drip lines laid out on vegetable crops on bedded rows and covered with black plastic. Don't know if this was T tape, though. However, with the surface use, it appeared the plastic was removed and the tubes rolled up after the crop was off. Don't think there was anything used to hold the tubes in place, though. When it comes to the fall, my neighbor blows out the main lines and the drain line at the other end. He doesn't try to blow out the T tape itself as it has the emitters so has very little to no water in it when not running, and if ice does form it can expand inside the tubing without problem since the tubing is pretty well empty. Whether or not you use a quick connect for blowing the lines out depends on how much time you want to spend blowing the lines out in the fall. Since my neighbor is using settled and filtered ditch water, at the end of each daily water cycle on each zone, he opens the drain valve on the drain line and blows water out for a minute or two to help clear any sediment and protect the life of his investment. I have heard many times that the lines should receive some treatment periodically to prevent minerals from depositing in the emitters, and to control any bacteria that may be growing in the tubes to prevent them from forming gooey deposits that will accumulate sediment and plug the emitters. Usually, this is done by injecting sulphuric acid or phosphoric acid into the irrigation water one or more times during the year to achieve the desired pH of the water to remove the mineral deposits. The frequency of this will depend on the mineral content of the water, though. They also use phosphoric acid, which is a weaker acid, but also provides phosphate fertilizer to the plants. Sulphuric acid will also fertilize the soil with sulphur, if it is needed. If you don't treat the lines occasionally, you are likely to end up with deposits that will gradually plug the emitters and shorten the useful life of the tape. In a garden situation where the cost of what you are using is relatively small compared to a field situation, shortening the life of the tubes by a few years may not be a concern, but it will depend on the mineral content and other contaminants in your water. Good luck!

Hi, gringojay; The terminology of deep ocean water (DOW) or deep sea water (DSW) by oceanology is a water created in only two locations in the world - one in near Greenland and another in Antarctic ocean. On the other hand, DOW in the commercial industry means all ocean water deeper than 200m (600'). I am talking about this commercial industry DOW. The difference of DOW from shallower ocean water and those on the land are; 1. Much cleaner because of no contamination from chemicals from land and less than 1/1000 bacterias compared to surface water. This is because no planktons can live without enough oxygen and sun light. 2. Much higher content of NO3, PO4, Si. These nutrients mostly from dead fish are not consumed by planktons. 3. Low water temperature and ingredients are very stable through out a year. Currently DOW is drown up at 19 facilities in Japan, anywhere from 400m to 1400m deep, for the use of marine products industry, agricultural industry, cosmetic industry, etc. One company whom I am working with has made a functional water by mixing their "treated water" and DOW. (I will explain about treated water separately.) They claim it significantly accelerates healthy growth of plant. I hope I don't sound like a snake oil promoter. I recommend you will experiment this functional water to see if it is a snake oil or not.

Typical well designed spray irrigation will at best be ~ 60% efficient WRT water utilization. Atomization in air, overspray, runoff, and surface water evaporation create the water loss and decrease efficiency. Most systems are so poorly maintained and not adjusted for seasons that this numbers is significantly lower. Typical well adjusted drip systems are more than 90% efficient with water use. Even when they are not adjusted for season, they conserve more water than even a fine tuned spray system. The challenge with drip is two-fold: 1. It is usually more labor intensive to deploy and maintain. 2. To meet the high efficiency number you must do a lot of figuring and arithmetic to design the system correctly. To the second point; A proper design requires: a) Calculating the daily amount of water each type of plant needs during the hottest, driest month. b) Determining the water holding capacity of the soil. c) Deriving from above data the best schedule for achieving the least frequent deep watering of the plant root zones while providing their daily need of water. If you spend a few rainy cold winter days figuring these things out, it can pay great dividend come growing season with healthy happy stress free plants.

Earlier on this post, green_devo mentioned electric conduit with large square nylon netting, which is a system I've used successfully for my pole beans, peas, cucumbers and tomatoes. Conduit is readily available at Home Depot, really long (10 ft.), comes in different diameters, is cheap ($2.00 ea. for the smallest dia.), easy to cut, and won't corrode. Pair it with nylon netting, heavy duty concrete mesh or livestock fencing using wire or zip ties to attach it, and you're good to go! You'll note that we've used pipe elbow joints and added conduit cross braces along the top, without any threading or gluing, since there's just enough tooth in the threaded joints to grip the conduit, but you could caulk those to make sure they don't loosen in strong weather. We usually sink 4 ft. of slightly smaller rebar 2 feet into the dirt, then slip 6 ft. long conduit over that spike, but if you need it tall, those could be longer; much easier to pound in the shorter, sturdier rebar than the longer conduit. This all breaks down easily (including pulling out the rebar) after the growing season is over, and stores compactly. Super happy with this system! By the way, notice the tomatoes at the left in the photo are sprawling and ready for trellising.