Solar Powered Hydroponics System

June 1st, 2013 | Comments | Share

Tags : solar hydroponics garden vegetables

Introduction

I always wanted to build my own hydroponic system and experiment with growing vegetables in a more controlled environment The biggest challenge growing vegetables is watering them. Forget to water them for a day or two and they take a week to recover! I say that a successful vegetable gardener has an automated watering system.

The System

We have wonderful plastic gutter systems here in South Africa. There are 4 or 8 meter lengths and various clip on connectors and end parts. They clip onto each other and with a bit of modification you can end up with a wonderful vegetable growing system. I have the hydroponic system running using these plastic gutters and a hanging garden system (more in another blog posting about them)

I first built an A-frame from wood, guessing the heights where I wanted to add the gutters. A safe height between gutters is just higher than what most crops such as lettuce and tomatoes would grow. I actually built it too high, but that wasn't too much of a problem as I needed space for the solar panel later. The wooden installation was painted with a protective coat of varnish to stop the wood from drying out and warping.

The brackets to hold the gutters were attached to the wood wedges I had attached to the a-frame. This kept the gutters more or less vertical. The gutters were then attached and the end caps added. At the end of each gutter I glued on a pipe connected and attached a plastic tube so the water can flow from one level to the next. On the A-frame, the gutters do not line up below each other so you need to pipe the water from one level to the next.

On the top gutter I added an inlet pipe and the pipe from the bottom gutter passes through a filter back into the 25 litre reservoir I use for the water. The reservoir, a large water container, lies on it's side so any excess water, from rain storms, can flow out.

Electronics

The whole system is controlled from the electronics box. I opted to use off the shelf items instead of building my own solar controller and timer. The timer is a 12 volt timer that pumps for 2 minutes every 3 hours. The small 5 watt solar panel is connected to the solar regulator and the battery is a small 7 Ah alarm battery.

At a later stage I want to add LED Grow lights, a strip of LEDs lights with the correct frequency for effective growth of plants. The strip will be added to the bottom of 3 of the gutters and will have to have it's own timer. The lights will come on early in the morning and go off once the sun is up. Once the sun has set, they will automatically come on and run till late at night. This should give the vegetables more growing time. The battery capacity will also have to be increased, as the led lights use quite a bit more power than the timer.

Planting

The gutters were filled in with a growing medium. I used small volcanic rocks, sold at local hydroponic shops and some nurseries. I then planted seeds in small rock wool plugs, which seem to keep the moisture forever. No more dried out plant roots! I also got some hydroponic food and I add 2 teaspoons to the 20 litre water in the reservoir each week. The old water is used to water the normal vegetable garden.

I have planted lettuces in one gutter and strawberries in the other. At the moment there isn't many baby strawberry plants to plant over. As new plants develop, I will add them to the system. I added some spinach seeds directly into the growing medium, instead of using the rock wool. It will be interesting to see if the plants can grow directly in the grow medium outside in the wind! I'm also trying dwarf bean plants, some planted in the rock wool and others directly in the grow medium. In the warmer months I will be able to grow tomatoes. I'm still trying to find other vegetables that we use that I can grow. It is important to only grow what you eat, do not plant vegetables that your do not regularly use.

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  Electronics

  The electronics! The solar regulator, alarm battery, 12V DC timer and the 12V water pump.

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  Rockwool in Growing Medium

  The rockwool plugs for growing seed, in growing medium

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  Solar Panel

  The small 5W solar panel used to drive the whole hydroponic system.

Future Ideas

In the future I want to build a version 2 of the system, that can be used for commercial farming. We have a lot of sun in South Africa. We can now grow vegetables in a water wise system, close to the markets in almost any area of South Africa. Someone got a farm for me?

Interesting Links

http://www.gizmag.com/bitponics-cloud-gardening/28119/
http://www.gizmag.com/plant-in-city-project/22960/
http://www.bitponics.com/