We set out drip tape late this weekend on all of the west side of Veg Hill and the line of blueberries north of the barn. Let’s just get this out of the way: drip irrigation is a MARVELOUS thing.
The process leading to our deployment of drip tape Saturday has taken about two months. Looking back on it, we could have (and probably should have) moved much faster, but we’ve had other priorities (like caring for the suburban home we still own and getting crops in the ground) that kept getting in the way. In addition, a couple of weeks ago we figured out that if we ever wanted to take down the last remaining free-standing trees on Veg Hill (to open it up to more sunshine), we needed to take them down before we stretched out the drip tape all over the surface. That was a good decision, by the way. The trees are down now, safely cut up for firewood, and their smaller branches are piled up waiting for the chipper-mulcher. For more information on the blow-by-blow progress of the irrigation system, go to the top of any page on the site and click on “Farm Log.”
Saturday we started about 4:30 stretching out the drip tape. We started with a short line on the west side that serves only the blackberries. Deploying the drip tape (we’re using 15 Mil T-Tape with emitters every 12″) proved surprisingly easy. I held the 4100′ roll of drip tape with a piece of 3/4″ PVC pipe (what else?) so that it spun freely, and Amanda walked with the tape end to stretch it the length of the row. When the tape was stretched out, we doubled over its end and then slipped a 3-inch section of drip tape over the doubled end to create a “plug.”
Then we poked a hole in the 1″ header with the plastic hole punch we got with our other drip supplies, inserted a valve with cutoff, attached the drip tape to it, and screwed it tight. The process of installing a drip tape onto the header hose took about two minutes.
For us, the most time-consuming part of the job was placing the drip tape in and around the already-planted veg. We’ll be installing drip tape on the east side of Veg Hill in the next couple of days, where there’s not yet any veg growing. I’m not confident of this, but I expect that process to be even easier.
The gratifying moment arrived when we turned on the water and watched all those tiny emitters begin to drip, dribble, and trickle on all our veg. No runoff, no water on the aisles; just water at the roots of the plants where they need it. It was delightful to view the water from the drip lines glistening in the late afternoon sun.
The other gratifying moment was the Sunday morning after a two-hour soaking Saturday night. The collards looked stronger, the banana peppers had perked up, the sweet 100s were fuller and more robust, and the beans had opened up more leaf surface to the sun. In general, Veg Hill now looks like everything planted there has kicked it up a notch.
Sunday afternoon while Amanda was busy in town I dug up the box serving the blueberries and the future greenhouse, where I had a slow leak. I found the leak and fixed it, and then I dug a shallow trench for the header to run from the box to where the line of blueberries begins. Emboldened by my success, I decided to run the drip tape by myself rather than waiting for Amanda’s help to do it. The blueberries got their inaugural soaking from drip tape Sunday night.
As with Veg Hill, the drip irrigation line for the blueberries gets the water right where the plant roots need it, and because it flows so slowly, the water flows down into the root structure rather than running off. When we have watered with sprinklers or even soaker hose, a good bit of the water runs off; with drip irrigation, all the water sinks into the soil.
We control the drip system using a Weathermatic SL 1600 controller mounted inside the shop. Right now it’s set to water on every even-numbered day beginning at 7:00 am. Veg Hell East gets three hours, then Veg Hill West gets three hours, and then the blueberries get 2 1/2 hours. Until somebody tells us this is a mistake, our assumption is that a deep watering that occurs every other day is preferable to a shallower watering that happens every day. The controller is expandable to add many more zones and valves and even to change the watering schedule automatically in response to rainfall and soil moisture, but we don’t anticipate getting to that point on our tiny scale.
I love the results we’re getting from drip irrigation, but I’m aware that we may be pulling up minute amounts of salt from our well and depositing them on our veg. Here in the short-term, this “salting” is not a problem. In the long run, however, if we continued doing this for many years, eventually it would decrease the fertility of our soil. One of our hopes for the future is to convert over to using surface water (in our case, from the pond) instead of well water. We understand that if we have been irrigating from well water for a year, NRCS (read that, you taxpayers) will help us with the cost of converting over to using surface water, but haven’t done the research to make sure that’s true.
Salt… we don’t have that problem, but groundwater here is often high in manganese and sometimes high in radioactivity. Also, wells in the eastern part of the county are sometimes contaminated by tobacco agrochemicals.
Large cotton fields often have contaminated groundwater underneath. I wonder about all those expensive homes in east Montgomery where the McLemore plantation used to be.
Ooh. That doesn’t sound good. We have cotton fields adjacent to our property. Fortunately, however, they’re well below us in terms of altitude, so I’d like to think the chances of our having our water contaminated by them are low (he said valiantly).
http://en.wikipedia.org/wiki/Disodium_methyl_arsenate, http://en.wikipedia.org/wiki/Monosodium_methyl_arsenate, and http://en.wikipedia.org/wiki/Lead_hydrogen_arsenate are the primary concerns here, with respect to cotton fields. You could have your groundwater tested. Note that according to http://toxics.usgs.gov/regional/cotton.html, there can be wide variation in regional practice for cotton chemicals. Some arsenic in groundwater here is natural, but it’s below the allowable levels.
Manufacturers of preserved wood for telephone poles, railroad crossties, etc almost always polluted their vicinity with http://en.wikipedia.org/wiki/Chromated_copper_arsenate, but that’s not likely to be a problem for you.