How does growing Green Onions help budget? | Worth one month natural gas cost

Winter is here. It is very hard to grow plants outside in Portland Oregon. So, we need to figure out how to grow plants indoor.

One of the easiest vegetables to grow is green onions. Let’s see how growing green onions help budget at home.

A bunch of Organic Green onions costs $1.46 now (12/01/2019).

If we figure out how to grow a bunch of organic green onions every week, we can save $1.46 * 52 weeks = $76 per year.

This is about the same cost as the average monthly natural gas cost in Oregon.


Here is one experiment over Thanksgiving holiday. We will focus on growing green onions efficiently to save money.

Green Onions grow faster by focusing on roots. Making roots longer and bigger is important.

What helps green onions grow so far are

  1. Gather multiple green onions in a group – Green onions help each other grow!!!
  2. Clean roots a couple of days per week

More experiments coming up!

  1. How does light help grow?
  2. How does oxygen in water help grow?

Let’s see how we can save one month natural gas cost by growing green onions infinitely.


Backyard Gardening #11: 2019 August Week 2 | Eggplants Party


It is becoming a harvest season. We had good hot days and a little colder days. Time to pick up vegetables !!!

2019 August Week 2


So many eggplants grew and time to pick them up. The eggplants were heavy…

With eggplants. tomato, peppers, and beans, made a vegetable face 😛

Eggplants, Tomato, and Beans
Measure eggplant dimension for fun


Eggplants, Ground Pork, Onions, and Tofu. Backyard garden to kitchen is very fresh.


Backyard Gardening #10: 2019 August Week 1

Outside Backyard Garden for Summer

Eggplants became too big in tight space now (stretching their shoulders 🙂 ). The middle plant below started to look stressed out by the side plants. So, it was time to move the middle one out of this area.

Now, this one has more space to grow horizontally and vertically. The leaves showed a little disease. So, I did a little bit of leaf cut.


Made Japanese “tsukemono” out of eggplants and cucumbers.


This is organic tsukemono, so we can only keep them fresh for a couple of days.

Engineering, Gardening

Backyard Gardening #8: 2019 July Week #3 | #SmartGarden #Recycle

Weekly Progress

Tomato started growing more as the temperature in Oregon started going up.

There are six eggplants and each plant now has a bunch of flowers. At the same time, they attract snails 😛

New Crops

Green onions. Bought green onions at a grocery store and kept them in a glass of water. Changed water every morning for two weeks and each has enough roots now. So, it was time to plant them outside.




SmartGarden Progress

SmartGarden device now is equipped with GPS sensor (Amazon Link) to keep track of real time information – GPS coordinates can be recorded as well. As the device has an USB charger block to power the Arduino microcontroller (Amazon Link) and other sensors, this became a portable device to check out brightness from the light sensor (Amazon Link).

The picture below shows the Analog Three-way meter and my own SmartGarden device.

LCD display shows Time and converted voltage by Light Sensor
SmartGarden Device with bell peppers
Engineering, Gardening

Backyard Gardening #7: Light Sensor | #DIY and #Arduino


Previously, the smart gardening device was built as an alternative method to the analog three-way meter (amazon link) shown in the picture below.


Using Arduino Software on Windows OS.

The arduino module used in this project is Arduino Micro (Amazon Link).

The data of light sensor output to Arduino are voltage values. In general, when it is brighter, the resistance value of the light sensor becomes smaller. As an example, about 100 Ohm in the sun light and ~ 10M Ohm in darkness.

Arduino microcontroller is programmed so that the log from Arduino produces the voltage value at a node of the light sensor every second. This indicates the brightness captured by the sensor. The data will be shown on the Arduino console and 4-line LCD.


With LED Desk Lamp, Arduino and Light Sensor (Amazon Link).

LED Desk Lamp has 4 light brightness levels


As the desk lamp gets brighter, the voltage value goes down. This means that the resistance of the light sensor goes down.


Test this prototype outside and compare the results with the analog meter.


Backyard Gardening #6: 2019 July Week 2 | #eggplants


What’s new?

Eggplants started growing faster.

Watermelon is still very slow as its roots need to expand more.

We’ve installed a tomato cage as it is growing big now. The tomato cage also helps grow upwards rather than left and right side.

Eggplant attracted a couple of snails 🙂

Any harvest this week?

Eggplants and blueberries.

Coming up

Start cooking straight from garden.


Backyard Gardening #4: 2019 June Week 4

Backyard Garden Highlight:

Our regular plants are growing faster as the summer is coming.

Now, strawberry season is almost over. Based on my experience, after strawberry, we are starting to collect blueberry. Yes, blueberry is almost ready.

This week, we purchased new plants from FredMeyer.

We like Japanese plants provided by Iwasaki Brothers.


New Plants:

Watermelon, cucumber, bean, and winter squash. Watermelon and winter squash grow horizontally. Cucumber and bean grow vertically, so they need some support.

Growing in progress:

Japanese Long Eggplant: I am expecting in a couple of weeks, start collecting some eggplants. Here in Oregon, we can harvest eggplants twice (July and September). 

Tomato: This year, I am trying to prune tomato frequently. Last year, I didn’t. So, when we went out for vacation, tomato started growing everywhere to left and right and up. When I came back in July, tomato plants grew so much that they fell down without support. 


Finally Blueberry is ready to harvest. This blueberry tree is three years old.


Engineering, Gardening

Smart Gardening #2: Concept Design by drawing Block Diagram

Last time, we studied the fundamental data to collect by a commercial Three-way meter (last Smart Gardening blog post). So, let’s review it again and start a DIY concept design in a smarter by drawing a block diagram.

Recap: Three-Way Meter, weblink

This three-way meter device can measure three different type of data and display them on an analog meter with a switch. One good thing about it is a battery-free device.

  1. Light Sensor
  2. Moisture
  3. pH
  4. Analog Display


Here is a smarter way to measuring gardening data with Arduino. Arduino is a low-cost micro-controller which can control sensors electrically and monitor the live data.

This is a list of components as the first prototype. We would like to design this with very minimal knowledge of electronics.

  1. Arduino Micro: Arduino Micro with headers
  2. 4-line display: SunFounder IIC I2C TWI Serial 2004 20×4 LCD Module Shield
  3. Light Sensor: Digital Light Intensity Photosensitive Sensor Module
  4. Soil Moisture Sensor: DFROBOT Gravity: Analog Capacitive Soil Moisture Sensor- Corrosion Resistant
  5. Temperature and Humidity Sensor: BME280 I2C or SPI Barometric Pressure and Altitude Sensor

This time, I decided not to use pH meter because there is not a low cost pH meter and we don’t measure pH very often. However, I may be wrong, so I will try to include it in the next version. In addition, as the three-way meter is a battery free device, it is good to add a small solar panel to charge the device in the next version.


Engineers usually draw block diagrams to share ideas as a Proof-of-Concept prototype. Microsoft Visio is a good software tool including business flowcharts and electronics block diagram as part of the software package.

This block diagram is very simple, and it shows that Arduino Micro is the brain of this smart gardening prototype ver 1.


I2C is a standard bi-directional two-line communication between a micro-controller and sensor including SCL (Clock) and SDA (Data).

SPI is another standard three or four uni-directional wires including SCLK (clock), MISO (Master Input Slave Output), MOSI (Master Output Slave Input), and CS (Chip Select).

Analog voltage is the voltage level that the sensor outputs to a microcontroller, so microcontroller’s ADC (Analog to Digital Converter) can quantify the voltage level which is based on sensor’s quantity (ex: soil moisture level and light luminance).

Next, I would like to start wiring and soldering to connect all components.


Backyard Gardening #3: 2019 June Week 3

Backyard Gardening Update in June 2019.

Finally, the weather in Portland, Oregon is sunny in most days. This means that vegetables that need sunshine grow faster.

Snapshot of the backyard garden:


Growing in progress:

  1. Eggplant: First eggplant. Expecting this to be ready to eat in a couple of weeks. With more sunshine, the plant becomes more dark purple.


2. Blueberry: berries are starting to be dark blue.



  1. Strawberry has been very good in the past week. Time to pick up a lot of strawberries.