Hey! I used to garden in California and now garden in the Pacific NW!

Some thoughts. These thoughts work for me in my garden; they may not have any universal applicability.

- I don't use drip irrigation to get a bed initially wet. For that, I use overhead watering, or flood it, or use some other way to get it sopping wet, deeply, just once.

- Half an hour is, to me, barely a start for drip irrigation. My goal with drip irrigation is to do it infrequently, but for a long time. So, for example, four to eight hours once or twice a week.

- However, that is not going to keep seed wet enough to sprout. Last year, we set the irrigation timers to drip for ten minutes every night, AND four hours every four days or so. Five minutes twice a day would have been better, but the timer didn't support being programmed that way.

- However however, the surface of the soil between the drippers may still be dry. That means that plants/seeds need to be placed pretty carefully next to drippers. If you're growing a crop that needs to be broadcast, the drippers may not work as a plan.

I tried to water my lettuce bed by drippers last year and grow lettuce from seed, and the lettuce only sprouted right next to the drippers. Which would have been fine if the drippers were just the right spacing for the lettuce. Next time, I'll set up those little dripper-sprayers instead.

1/4" drip tubing takes a long time to deliver much water so no, 1/2 hour is nothing. This isn't going to show you much. Plus it isn't the surface that needs to be wet it is the soil below and it is much wetter than the surface.

Run your drip lines for 2 hours straight. They are normally set to deliver 1/4 gal. per hour (which isn't much). Then stick your hand down into the soil 3 knuckles deep and feel out wet it is and how much the water has dispersed out to the sides. That will clue you into how long you will need to let it run once planted. Best estimate - depending on the plant needs - is 3-6 hours run time minimum.

Another trick you can try is to take a small tuna or cat food can, measure its depth, set it right under one of the drippers, bury it in the soil so the rim sits even with the top of the soil so the hose isn't running uphill, and time how long it takes to fill up the can. Then you know you have delivered x inches of water to the bed.

Hope this helps.

Dave

Thank you, I have a feeling I should just continue to overhead spray the bed when the surface is dry until the seeds sprout, along with possibly getting a couple of those drip mister/sprayer heads. Thanks for letting me know about beneath the surface. I'll check there as well.

Digdirt2, if I run the line for 2 hours straight and then see if I need additional hours, how many days a week do I do this? Twice?

Last question, and once again I am clueless on this stuff, but I have a pressure valve attached to a timer but I don't really know how high to turn up the water. Any suggestions here?

continue to overhead spray the bed when the surface is dry until the seeds sprout

Sorry I didn't realize you had seeds in this bed. I read your post to mean you had just set up the bed and were testing how to use the drip system.

Drip irrigation is not used to start seeds because it doesn't moisten the soil surface. It is used to water transplants and established plants only, to deliver water down to the root level. So if you have direct planted seeds there then you will have to continue to overhead spray until they sprout and develop roots.

The 2 hour suggestion was for a test run (rather than the 1/2 hour you used) to learn how the system works and how it would water future plants. 2 hours is NOT sufficient for watering once the plants are established. As we both said above drip systems using only 1/4" tubing require several hours of run time to effective water the bed.

As to how often? Watering plants is never a set schedule thing. It is "as the plants need it" and many variables determine that - weather, temperature, type of plant (different plants need different amounts of water), age/size of plants, growing mix used, etc. Sometimes it may be once a week, sometimes 2-3x a week and sometimes once a month. You have to learn to read your soil moisture levels and read the plant symptoms when it comes to watering.

The role of the pressure valve is to prevent over-pressure in the system than can blow the lines. It is automatically set at a specific pressure of 10, 15, or 20 lbs. and should be labeled as such. I don't know what valve you are using. Most 1/4" systems are set at 10 but if you have 1/2" delivery hose it may be higher. I also don't know what your house to main hose pressure is - that is often anywhere from 25 to 50 lbs. So as a very loose guideline you turn the faucet on no more than 1/2 way. But you will have to see if that is enough to provide consistent steady dripping from the feed lines without any signs of backup pressure.

Hope this helps.

Dave