Not A Ray-gun

Well, today, I built the "Assembly" for our drip irrigation system. It looks a little like something that, with the proper paint, might work on the set of Deep Space 9.

Water flow is right to left in this photo.

My supply line is a 1/2" pipe, but the Assembly is built around 3/4" components. I chose the 4" long, 3/4" nipple so I'd have something I could brace against the wall of the greenhouse. The next thing to the left is an in-line ball valve (in the photo the handle is removed). Then the small-ish, black thing is a vacuum breaker. That's followed by some adaptors sandwiching a swivel hose coupling. I included the coupling so I'll be able to remove the fancy (i.e. expensive) downstream bits during the winter.

Next downstream from the swivel hose connector is a check valve. The combination of the vacuum breaker and the check valve prevent any siphoning of water out of the drip system and back into the supply (ick).

After the check valve you can see a filter. The bottom, dangly part can unscrew so the stainless steel filter can be removed for cleaning. Next there's a pressure regulator. That brings the pressure feeding the drip lines to 30 PSI (which is within spec for the drip tubing I'm using). Finally, you can see a "Y" valve with individual shutoffs so I can use the assembly to drive two separate garden areas.

Today I got the upstream bits -- up to and including the swivel hose fitting -- connected to the water supply and fastened securely to the outside wall of the greenhouse. I've put the handle back on the ball valve. No leaks on this part at all. The braces work superbly so there should be no strain on the plastic supply line to the greenhouse.

As I mentioned in an earlier post, I got most of the Assembly components from a place called DripWorks.com. Their prices were good (very good in some cases) for the specialty bits. The standard pipe fittings were competitively priced at the local hardware store. The stuff from DripWorks arrived promptly.

Next I need to brace the rest of the bits and then start on the actual drip array. I'll probably work on that tomorrow.

Drip Components Ordered

Well, after futzing with the water supply in the greenhouse for a few days, I think I've got a hose bib and a "T" pushed through the wall of the greenhouse. There's a slight drip -- a couple of them actually -- in some of the connections between dissimilar materials (metal-to-plastic) but according to the USGS estimate of one drip = a quarter milliliter, that only amounts to about 12 gallons per year. Actually it's about 9 gallons per year because I shut the water to the greenhouse off from mid Nov through mid Feb.

I put a yoghurt container beneath the worst offender (less than a third of a drip per minute) and will use that to water plants in the greenhouse. Actually I'm hoping that there will be enough minerals in the water to plug these tiny gaps over the coming months. I've seen that happen.

I'll connect a drip irrigation "assembly" (vacuum breaker + check valve + filter + pressure regulator + assorted transition fittings and an in-line valve or two) to the T that I've brought to the outside of the greenhouse. The assembly will drive a header that in turn feeds ten "laterals" of drip tubing w/ in-line emitters. Each emitter is 1/2 a gallon per hour. Each lateral will be about 22 feet long (i.e. 11 gallons per hour per lateral). So that means the upper garden drip system will output 110 GPH. The header tubing can supply 480 GPH. The drip tubing can operate at pressures of 10 - 50 psi. The pressure regulator I picked has an output value of 30 psi.

In other words, the Old Amigo thinks he'll neither parch nor explode his drip system when he turns the water on.

I think an hour every other day will probably suffice for a well-mulched garden. That works out to 1650 gallons per month, roughly. I hope I can keep the soil moist with less than that, but we'll see. This system has the virtue of being fairly easy to dismantle for garden winterization and spring cultivation.

I'm also putting a "Y" hose fitting on the output of the assembly so that I'll be able to feed another drip system in the lower vegetable garden, but I'll want to debug the main garden before I tackle that.

Today I ordered most of my connectors and fittings from http://dripworks.com/ (recommended by an organic farmer, whom I know slightly, down in Chimicum).

The guy at dripworks seemed knowledgeable and "into" it. Said I should get my stuff early next week. I'll have to buy a few other items from the local hardware store, but that's okay. For simple, basic plumbing bits, the local guys are actually pretty competitive. They were more than 2x the cost of the in-line emitter drip tubing, however, and that tubing represents more than half the cost of my drip system (including the lower garden).

That's the garden story... for today anyway.

Garden Prep

Yesterday I spread (roughly) a cubic yard of freshly-cooked compost over our main garden area. Then I turned over the whole plot - about 350 square feet. This upended the winter rye cover crop. The soil looks good; although there is quite a bit of variation. Some areas are slightly more sandy and other areas have more of a heavy, clay-like texture.

According to the Pacific Northwest Garden Guide, I should now be working on getting the soil warmed up. I should also do something to keep the spring rains off the garden. The soil, after all, should be moist. Right now it is heavy and soggy. Our forecast calls for four days of sun, however, so by Sunday, things should be good!

Since we're planning to move to a drip irrigation system for (at least) the main garden, my next project involves bringing a hose bib out through the wall of the greenhouse. The Old Amigo is a tad nervous about tackling the plumbing, but the line to the greenhouse has its own shutoff. That at least will prevent serious disruption to the main water supply.

Oh, and I picked up a copy of an excellent book on drip irrigation. It's called (remarkably enough) Drip Irrigation for Every Landscape and All Climates. The author is Robert Kourik. I ordered my copy from Barnes & Noble.