The DIY Smart Garden System

I’m going to take you on a tour of Do It Yourself Smart Gardening

My name is Cory, I’m a Technical Craftsman specializing in creative problem solving within electronics and software engineering.  Professionally, I’ve worked as an electronics engineer, a plastics fabricator, software engineer, an industrial laser technician, and, of course, a coffee barista.  I’ve spent the last several years working on a Smart Garden System project I named, hydroMazing.  I’m sharing my work with you because I would like to empower everyone who is interested in a “Smart” approach to gardening.

What we’ve covered so far:cropped-hydromazing_smart_garden_system


Are you interested in following me on this journey?

Now that we have an understanding of what it takes to provide an optimum indoor growing environment we can start analyzing the cost-benefit of further optimizing and automating the system.  Please share with friends and follow to receive a notification when I publish the next section.

Section 1:  Let’s start by using an Arduino Nano on an Expansion Board to monitor the indoor gardening environment.  We will measure light intensity, ambient temperature, relative humidity, nutrient/water temperature.

Section 2:  Continue working with the Arduino Nano on an Expansion Board to control appliances in the indoor gardening environment.  We can continue working directly wired or we can start working with wireless communications.  Wired or Wireless?

Section 3:  Add an Arduino Uno using an LCD with Buttons Shield to provide a display and alerts.

Section 4:  Add the Raspberry Pi for remote access, notifications, data collection, and analytics.

Section 5:  More sensors:  moisture probe, pH, E.C., carbon dioxide level, flow-rate, liquid, float (liquid level switch).Peristaltic Pump

Advanced:  Using Dosing/Peristaltic Pumps for Nutrient Solution Management.

Using a Raspberry Pi and USB Camera  Use Raspberry Pi to monitor or collect snapshots of the garden using a USB webcam.

Coming Soon:  hydroMazing Smart Garden System Kit

Kit includes wired and ready sensors and components for making the Controller Module (Arduino Nano) and Web Services Module (Raspberry Pi)?

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Managing Nutrient Solution Systems

A nutrient solution system typically consists of a two or three part liquid solution containing the essential diet for a plan added to clean tap water.  The manufacturer of the nutrient solution will include or reference a feeding schedule recommended for various common types of plants. Unfortunately, most minerals are mined and processed by the manufacturers, however, many offer an organic option while some specialize in only organic.

nutrient starter kit

I recommend starting with General Hydroponics Flora Series Performance Pack, consisting of the main three liquid parts, several enhancements, and the pH test kit.  There is also an organic line of products. (Handy tip: If you ask General Hydroponics or other nutrient solution vendors for samples of their products, you can usually get free or discounted trial sizes.) A word of caution about miracle growing fertilizers, do not add any fertilizers other than those you know to be hydro-friendly, as it can cause a nutrient build-up harming your plants.

Making Your Own Nutrient Solutions

There are several challenges involved in making your own nutrient solution.  Sourcing the raw minerals needed, breaking-down properly so that the plants are able to absorb the nutrients, and filtering out unwanted materials that will clog the flow of nutrient solution through the system while maintaining a proper pH and hoping that you didn’t inadvertently introduce an undesirable pest into a closed-system.

Experiment with microfungals:  Make your own hydroponic compost tea

Nutrient Solution Management


The most common vessel for transporting and storing water is the 5-gallon plastic bucket, also commonly available in 3-gallon as well.  The most common method for managing liquid is to use ½” diameter vinyl tubing and fittings.

If we do not monitor the nutrient solution concentration and the pH then the plants will reach a point where they will show signs of stress.

What is EC?

The electrical conductivity (EC) of water estimates the total amount of solids dissolved in water -TDS, (Total Dissolved Solids). TDS is often measured in ppm (parts per million). In hydroponics, this measurement is used to determine the approximate concentration of nutrient solution to water.

As the nutrient solution level decreases it needs to be replenished with freshwater, otherwise the nutrient solution becomes more concentrated and some plants won’t respond well. Add fresh water to bring the concentration back to the level it was when started, often referred to as “topping-off.”

What is pH?

The pH of water is an important measurement whether you are gardening indoors or outdoors, soil or soilless, because it affects whether a plant can properly take in nutrients.

Check the pH and EC periodically and compare it to what is expected for that plant at this stage of growth.  There is no need to adjust your pH or EC until it is necessary. There is a lot of misinformation out there about keeping the pH and EC regulated. If I were paranoid, I’d say it was a conspiracy from hydroponics manufacturers and retailers who want to sell more consumable product. Don’t get me wrong, proper pH and EC is important, even critical, to the success of a plant.  There are many hand-held EC devices available as well and if you are checking the E.C., it’s a great time to check the pH.  Therefore, I recommend a handheld pH tester such as the Oakton EcoTestr pH 2 Waterproof pH Tester, which is excellent for the home gardener and has been proven time and again to be accurate.

When do I need to adjust the pH?

Only under the following conditions:  pH is at or below 5.0 or above 6.5

AFTER at least 30 minutes from the time of topping-off or changing the nutrient solution.  I recommend using a solution made specifically for this purpose, pH Up and pH Down from General Hydroponics sparingly and only when necessary.


Flushing means to literally flush empty the nutrient solution from the hydroponics system and replace it with fresh “good” tap-water. Then return the nutrient solution back to what it should be for the phase of growth. When in doubt, flush the system and refresh the nutrients. Otherwise, it’s recommended to flush your recirculating system every 7 – 14 days. When I grow, I try to keep the nutrient solution working as long as possible, however, salts build-up over time and it is good to flush with fresh water from time to time.

Using float switches:

  1. Top float switch used to indicate vessel is full of liquid.
  2. Middle float switch provides warning or triggers a pump to refill.
  3. Bottom float switch turns off pumps and notifies attendant that vessel is out of liquid.

Flow-rate:  A hall-effect flow sensor’s data can be used to determine the flow rate of the liquid being pumped.

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Digging Deeper into Indoor Gardening

What do plants actually require in order to grow well?

It is important for context and it is important for every human to understand what it takes to grow plants, even if the future doesn’t allow for outdoor cultivation.  At a minimum this is my effort to prevent future generations from suffering the fate of a World without plants as proposed by Mike Judge in his movie “Idiocracy” where people no longer understand why plants wouldn’t want to live on a beverage containing “electrolytes.”

Regardless of which method you choose:  soil, hydroponic, or an aquaponics system, none will be able to compensate for poor growing conditions such as improper temperature, inadequate light, or pest problems.  Indoor grown plants have the same general requirements for good growth as field-grown plants. The major difference is the method by which the plants are supported and how the inorganic elements necessary for growth and development are supplied.

Let’s start out by discussing what it takes, at a minimum, to grow plants indoors and then look at ways to improve, scale in size, and automate the mundane.


Quick review of growing in soil

When we think of home gardening, we typically assume the plants are growing in soil.

Soil makes sense.  Plants in nature grow in soil, some maybe fortunate enough to receive a freshwater stream but most plants use their roots to seek out and locate water and nutrients.  Seasonal sunlight provides the light intensity needed for photosynthesis.  Temperature control is achieved by combining the sunlight with the wind to create a comfortable growing environment, while frequent rains bring the water needed by the plant for both nutrient uptake and respiration.  The plant can rely on signals such as the change in daylight and weather to indicate that it is time to flower.  Pollination occurs from the wind or bees and other insects that enjoy a sweet nectar as reward for their services.  Pest control is handled by the natural order when a predator insect finds, catches, and eats the pests on the plant.

As with most in life, It need not be a binary decision.  We don’t have to create a sterile environment for plants to thrive indoors.  In fact, I prefer to grow with hydroponics indoors and include a compost tea that I make from soil!

Going Soilless



Growing plants indoors without soil is a lot easier than you may think.pothos

If you or a friend have a common houseplant, such as a Pothos or Philodendron, then you can try out hydroponics without anything more than a small jar and tap water.  Using utility scissors, clip off a small 4-6 inch section of the Mother plant that has a few healthy leaves.  Wash and rinse a jar, then fill with clean tap water to about half of the jar. Rinse the clipped portion with tap water and insert it into your jar.  Ideally, you would feed the plant by supplying a small serving of nutrient solution, without it very little growth will occur. Place the jar on a dark shelf where the leaves can hang out into the light.  Within a few weeks, you should see some root growth.

Why not just grow ever plant the same way as the Philodendron?   The plant is hardy and can tolerate most indoor living conditions.  The same plant would grow much faster if we provide it with a more stable comfortable environment and aerate the water with an aquarium air pump.  Additionally, most plants are not as tolerant of the cloning process, removing a clipping and expecting it to grow roots, without an anti fungal to prevent root rot and a rooting hormone to encourage root growth.  Also, that formula is not recommended for plants that produce food.

Plants that produce food require more.

What types of plants grow well indoors?


Leafy greens (lettuces, spinach) herbs:  parsley, cilantro, oregano, thyme, chives, mint), strawberries, tomatoes, cannabis, exotics, etc.  Squashes and the like require a great deal of space as they mature enough to produce fruit.  Onions, carrots, turnips, radishes, and especially, potatoes, require a lot of root growth space.

hydrotonContainer and growing mediums

Clay Pots, grow bags, but mostly, plastic containers and PVC Tubing

Common soilless options:  rockwool, expanded clay pellets, hydro stones, vermiculite, perlite, coco coir, peat moss, sponge

What do you need to setup a complete indoor garden

Equipment needed for lowest-cost method of growing indoors



  • Tent or confined structure
  • Fluorescent Light on an outlet timer.
  • Intake Fan / Exhaust Fan
  • Containers
  • Water / Nutrient Solution
  • Air-pump ( aquarium-style) and tubing


  • Temperature / Humidity Meter
  • EC Meter
  • pH Meter

We need electricity and a way to get water to the grow site.

  • Lights
  • Ventilation
  • Water quality, Oxygen, and Mineral Nutrients


Consider whether you are going to be sharing your living space with the plants?  If so, then you will need an indoor growing tent.  



Important factors to consider include:

  • How much space do you have?
  • What do you want to grow and and how much of it?
  • What is the cost of equipment and how much time do you have to spend maintaining the system?

If you are fortunate enough to have access to a greenhouse, terrarium, or sun porch then you can take advantage of our natural sunlight.  If you’ve not grown in those environments or don’t have one, then you might want to convert an entire garage, basement, or other room? However, before you do that, I highly recommend you start with a small to medium-sized grow tent, which you can then setup inside of a garage, basement, or other room creating a smaller micro-environment.  Even if you plan on scaling to a larger size, then you’ll be glad to have the tent environment so that you can use it primarily for starting seeds.

Plants grow well only within a limited temperature range. Temperatures that are too high or too low will result in abnormal development and reduced production.

  • Warm-season vegetables and most flowers grow best between 60° and 75° or 80° F. 
  • Cool-season vegetables such as lettuce and spinach should be grown between 50° and 70°F.

Think about safety when setting-up your indoor garden.

It is a very good idea to use a GFCI adapter for your AC outlet if it does not already have one. Good quality extension cords can then be attached.  I often use the top of the tent as a place for the electrical cords to meet and connect to an extension. It is important to keep electrical cords a few feet or more off of the floor / ground in the event an overflow or flooding occurs we do not want to create an opportunity for electricity and water to mix.

recommended equipment:

48” x 48” x 80” indoor grow tent

24” x 24” x 48” indoor grow tent

Setup a tent, or closet, or spare-room.

A search on Amazon will result in many options and many sizes.  Whatever size of tent you think you have space for, imagine the tent taking up a little more than that and reconsider.  Trust me, I’ve made this mistake more than once 😉


Next Up:  Maintaining your Indoor Garden

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