Tuesday, August 31, 2010

Gravity Watering System comes online

The gravity feed watering system came online August 10th and is functioning wonderfully well. I finished the connections and filled up the main supply tank a couple days earlier to make sure the tank was going to hold water. The patch performed perfectly and the tank only had one minor leak in another area that was not of concern until I drain the system for the Winter. Phase one has been a complete success. One full tank will water the plants that I have now for two to three weeks. Each plant gets a gallon of water supplied to the roots as you will see in the following pictures and explanation.

Coming out of the main supply tank I connected a shut all valve to the drain plug hole. The one thing that I wanted in this system was to be able to shut off the water anywhere in the system to be able to work on the different parts. Maybe I overkilled a little but the many shut off valves will be quite handy.

The hose connection follows the fence line through the three weeks of weed growth to the secondary supply tank. I found that water volume is needed for gravity watering to work.

The connection to the secondary tank is to the PCV valves with special hose thread connections. I discovered that the hose threads are different than pipe threads. I've yet to find a converter to go from one to the other, but have master minded ways to get around the differences. In the PCV world threads to fit a hose are called MHT (don't know what it stands for) and threads to fit pipes are call MPT (again don't know what it stands for). Much trial and error fittings were assembled at the Lowes store to come up with a workable solution. Alas the answer came forth. Persistance at the Lowes store always nets the answer.

If you look close you will see the difference in color on the 2x2 strapped to the secondary tank. This 2x2 has been dunked in a hole in the top of the tank and the bottom darker color is wet from water in the tank. It gives and indication of how full the tank is. Water will seek its own level and in this case the water level in the black secondary tank is at the same level as the water in the main tank in the first picture. I raised the tank up off the ground so the water level would be the same as the main tank when it was full. This tank holds about 30 gallons and on it own would water one bed three times.

The gray box on the right is the heart of the whole system. It is an automatic timer that turns the water on and off at designated times. In the heat of the summer I have the timer set for 6am to turn on for five minutes. In that time enough water will run into the final distribution tank to water 4 tomato plants and 4 cucumber plants with one gallon of water for each plant.

This is the final distribution tank. It's a 3 inch PCV pipe with holes drilled to glue drip irrigation connectors in the holes. The hoses are the hoses for the drip irrigation. This tank has been made for the bed with the four tomato plants and the four cucumber plants. One hose for each plant will be positioned at the root base of the plant.

This is a look at the distribution tank in position cradled in the holes of two up right concrete blocks with a slight slope to the opposite end of the tank. There are two hoses in each distribution tank. One is for the water to enter the tank when the timer turns on the water flow and the other is a air drain hose to allow the distribution tank to drain after the timer shuts off the water flow. The end not connected to the tank needs to be positioned higher than the water level of the secondary tank to keep the water from bubbling out the end of the hose.

It all seems to work good for now. I just got back from a two week trip and everything looks to be in good watered condition. This is another picture of the hoses going into the distribution tank.

The end of the hoses that actually water the plants are held in position by pinch clothes pins. It's the best thing I've found to hold the hoses in the right place and not squish the hose.

It's been a summer project that took a while to get put together. It was kind of a design as I worked kind of project. When I needed to go to the next step the idea for that step just came into my mind. It was kind of fun to see things come together at the end.


  1. Thanks for posting this! I am brainstorming a similar system to use my laundry and bath gray water for my garden. I just need to do some fittings on the main lines, which involves crawling under the house...maybe I'll wait til it gets too cold for the spiders;)

  2. Dave -

    We could possibly be blood relatives! I live on 2 acres in the country in northern NY with a 28' above ground pool which runs my well dry after 40 mins trying to top it off in the spring - and 600' from a river. I'm trying to figure a way to build an underground cistern (cheaply) to capture rainwater or pump some back into the cistern in the fall (recycling water so to speak). might even build a small one to use for watering the garden.

    Anyway - "MPT" means "male pipe thread" (you can therefore figure out "FPT") and hence MHT is "male hose thread" and vice verse for FHT.

    The difference - pipe thread is usually a tapered thread to help with avoid leaking - while hose threads are straight - hence you need the round red washer in the female end of the garden hose.

    I'm not that smart - I read about it on the internet. Twenty years in the Army - you get this urge to find out what every single acronym and abbreviation you see means - GMD (get my drift)?

    Good luck to ya! God Bless.

    Noel in NNY