Project 002-044 Hydroponics Garden

With water scarcity, a different, more controlled manner of growing our own food is required. With the small number of gardens and limited crops currently in production, a water use in excess of 100 litres per day was not sustainable. So, we purchased a number of small Hydroponic systems and set about creating something more sustainable.

The units we have settled on are "A-Frame" style PVC 72 site units, and we anticipate having 2 of these to start with, for a total of 144 sites. We have purchased a 218 site unit and 4 of the 36 site units. Together with a 6 pot dutch jug system. In total, 512 sites in 5 different configurations. An area has been cleared an allocated to the Hydro-garden project. We have erecting a shade cloth over this 3 metre by 6 metre area to help protect the plants from the heat of the day during summer.

To reduce energy consumption in this project, these units will be aerated using small solar powered air pumps. The water/nutrient pumps will be solar powered, and the system for recovery and draining will be operated from the main solar system on a 12 volt line, replacing the standard 230 volt pump that is provided, with each kit.

Other than the hydroponic part of this experiment, there will be an ESP32 build component and a return nutrient solution element. This will control the watering times, duration, volume and record the necessary data to enable the functions to occur. Aeration will happen during the times that the sun is shining and solar product for that system is operational. The pumps while solar powered will be ESP32 controlled. Each of these 8 units can be individually programmed to function within a predefined matrix of environmental conditions. Each ESP32 is Wi-Fi enabled, and the data captured will be published to the project page for general consumption and use within the project conclusion and future funding.

Aim

Improved food production and more controlled water use for cropping operations. We are seeking a sustainable outcome for cropping in arid environments.

It will be important to measure and capture data which demonstrates relationships between factors, so that clear patterns can be established. This will allow the formation and establishment of patterns and practices in this area.

Method

Establish a measured Computer controlled environment for our Hydroponics experiments. The computer and monitoring will integrate with our existing weather station data and include some new sensors to measure:

Water flow
Evaporation and plant consumption
pH levels of tanked and return flows
When plants require watering
Water temperature
Solar availability
- Amount of sunshine and Lux rates
- Length of Day/Sunshine
- location of sun during the measured day
- Cloud cover
- Rainfall - not that this directly impacts the flow of water to plants, but it usually means, higher humidity and less sunshine
Time of flow - subject to conditions
Length of flow - subject to conditions
Volume of flow - subject to conditions

Establish a number of computer controlled Hydroponic Systems, from which we can:

Establish Growth Rate differences between soil and soil-less cropping
Measure water use
Measure production yield
Define suitable crop type for Hydroponics
Compare results and costs to Aquaculture water use, production and crop yields.

To maintain a constant water temperature (at ambient) each recovery tank will be 20 litres and buried to 3/4 of its height.

Watering System Development (Version 1.0)

The first prototype was developed using an Arduino Uno board. Using a DS1302 RTC module, an AMS1117 5v converter from 12 volts, and two 5 volt relays, capable of 12 volts at 10 amps.

This was neatly installed into an Arduino case. The 3 bolts visible at the bottom of the box are the terminals for the various functions of the unit. From left to right, the first terminal is the drain terminal, the middle terminal is the watering pump/solenoid terminal, and the third terminal is common ground.

Conclusion

The project seems to be very productive as a whole. The initial planting has yielded some exceptionally quick growing leafy vegetables like lettuce and kale. As the project continues planting will include some more demanding crops such as pumpkin, melon, cucumbers and tomatoes. As it is now late summer, these will need to wait until next spring for planting.

Planting

A small number of inexpensive seeds were initially planted to dial-in the settings for the Automatic Watering System. The automatic system was built and deployed to the Hydro-garden on the 19th of February 2023.

It is appreciated that some plants will not adapt to the hydroponics growing methods, such as root vegetables like potatoes and carrots. However, these can still be grown in purpose built gardens that are tuned to this kind of production.

Water Use

In the height of Summer, the current water use for each of the Hydro-gardens is around 10 litres per week. This makes a total consumption of around 354 litres per calendar month. If this is considered against the soil garden requirements of around 105 litres per day (3,255 litres per calendar month) the water saving is around 89.12%.

Automatic Watering System (Version 1.0)

This proved to be an excellent design, although it didn't have many of the necessary data capture features of the initial project scope. This is going to be version 1. It delivers the very basic functions of running a watering cycle at 7:00 am, 10:00 am, 1:00 pm, 4:00 pm and 7:00 pm. The watering cycle runs for 15 minutes. This is immediately followed by a two minute drain cycle. This allows the normally closed solenoids to be activated to cause the respective hydroponics frame to drain. Where the solenoid is a normally open configuration, it is connected to the watering cycle of the system. This allows the solenoid to be activated during the watering cycle to allow the planting tubes to fill and cascade.

Version 2.0

Version 2.0 was developed, which was WiFi enabled and used the ESP8266 rather than the Arduino.

This unit updated its own time at 11:40pm each night using an NTP server. The watering times were adjusted to be 5 minutes past the hour, so 7:05 am 10:05 am, 1:05 pm, 4:05 pm and 7:05 pm. A similar unit with programmable timing was given to Shayne and Jo for their conventional garden watering system. (See images below)

Amendments

The amendments to the Hydro-garden is just that of the Growing Solution Part-A and Part-B. There are no additional amendments required.

Cost-Benefit Analysis

The hydro-gardens are about as expensive to establish as the soil gardens. This is considering the amount of additional inputs required to start the soil gardens. The imports included potting mix, planter pots and fertiliser. The Hydro-gardens are a once-off capital expense, which should last many years. It is also noted that many of the soil garden inputs are required annually, and are therefore ongoing.