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drip timing/intervals

Posted by hydroman333 Davis CA (My Page) on
Fri, Jun 3, 05 at 0:11

I have a drip setup where there is a ebb/flow tray (cept not used for that purpose) and inside there are a few 2 gal mesh pots. 1 has 1 bush tom, one a sweet bell pepper, other 2 have a english cuc each. they are all in hydroton.
I have drippers that drip 2 GPH. I am wondering how often and how long i should run the drippers. I have a very large (3' by 5') south facing window and a 150watt HPS light. they were taken from ACE hardware in soil. I rinsed the roots and put them in hydroton. I have been running during all lighted hours. theyre 1 week since i got them at ace. I run lights from 7 AM to 10 PM and keep window open. It gets about 85 degrees max in the day and goes down to 65-70 at night.
thanks, tristan


Follow-Up Postings:

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RE: drip timing/intervals

First things first: you are giving up the premier advantage of hydro by bringing dirt-raised plants with the associated pathogens into hydro. You will stop doing this when all your plants die.

If you have good drainage in the tray, ie, the nutrient never puddles in the tray, run the dripper when the lights are on.


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RE: drip timing/intervals

hydroman333,

I think you have a pretty nice set up and have done things that will work out well.

willard3 is right that if you have any soil left on the roots that it can cause problems. However, a lot of people have managed to wash the roots cleanly to get their crops out hydroponically.

If I were to split hairs, I would put more light on the plants, but you really should be OK.

You really should have no problems if you leave the emitters going constantly during the light cycle.

That said, if you run 15 minutes ON and 15 minutes OFF during the light cycle especially while the leaf space is smaller might get you a little bit quicker growth.

If you buy a special timer and run 1 minute ON and say 4 minutes OFF, you still will be OK.

Many people start the watering cycle about 10 to 15 minutes before the light cycle starts.

Keep an eye on your plants. They will tell you what they need.


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RE: drip timing/intervals

alright thanks for all the advice, i did make sure to clean the roots well, and im running the drippers just during light cycle. they look like theyre growing pretty well, but i might try the 15 on/ 15 off. Thanks alot


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RE: drip timing/intervals

Washing the roots always worked for me. I did it with tomatoes, laurel and a small pine tree. The younger the plant, the easiest. You should know tha I never managed to scrub the roots completely clean.
As an experiment i planted a basil plant i bought at the supermarket without washing the soil at all,in huydro.Four months ago,I planted it in a big plastic colander with an airstone bubbler in a bucket.
Plant grows fine, no sign of germs or patogens, so far.
Have fun, experiment, be logic and realistic, most of the time it works.


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RE: drip timing/intervals

Drip Rate and Drip Interval should be based on good assumptions.

Drip rate (gal/hr, ml/min, etc.) should exceed the transpiration + evaporation (T+E) rate of the plant(s) during the day. Environmental factors affecting T+E are Light, Temperature, Humidity, and Wind.

How to determine T+E. Measure the amount of water needed to return your nutrient solution to its former volume after a couple of days. Divide that replacement volume by the number of days times 24 will give you the T+E rate per hour. For example my fig tree T+E rate is about 1.2 gal/day or .05 gal/hr. So a 1 gal/hr dripper is more that sufficient drip rate in my case.

Drip Interval (DI) is the on/off cycle. Knowing your drip rate multiply that by your on/off ratio will give you your average drip rate. For example if your DR is 1 gal/hr with a 15 min on/15 min off cycle multiply 1 gal/hr by 0.5 = 0.5 gal/hr average DR.

For nutrient solutions that are not aerated prior to drip then a drip interval is a good idea. As the nutrient drains out during the "off" interval air (read oxygen) is pulled down into the root area.

Change drip rate or interval at night? I think it's agreed that most plants transpire during the night. So a drip interval should be established for the night cycle as opposed to leaving the drip entirely off during this period.


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