HYDROPONIC SYSTEMS

There are a wide variety of different hydroponic systems. Each has its own characteristics, advantages and disadvantages. In general, I have chosen systems that provide a high density level (plants per square foot) since I don’t have a large yard. Check out these different systems.

NFT System (Nutrient Film Technique)

This is a system that I purchased from American Hydroponics. NFT systems are fairly simple – a shallow flow of nutrient solution passes through the bottom a channel so it is in contact with roots of the plant. A small electric pump moves the water from a reservoir to small 1/4″ tubes that are attached to each channel. At the end of the channels, the water is collected and goes back into the resevoir. One downside to this system is that when the water stops flowing (in a power outage), the plants wilt very quickly.

I liked this system so much that I installed a second system that is outside on my driveway. I found that different varieties of lettuce grow better outdoors than in the greenhouse. Notice the dark red greens in the outdoor system.

I recently rebuilt the greenhouse NFT system to a 3-tier vertical system. This doubled the capacity to almost 700 plants in about the same footprint. Also, I use a number of LED grow lights to supplement the natural light in the greenhouse. With the LED lights, lettuce grows year round.

Vertical and Horizontal System (Home made)

For Maker Faire 2019  I wanted to modify the A-Frame system diplayed in 2016 and 2017 so that it is easier to build. While the A-frame design looks nice, some of the materials may be difficult to get and assembly is a bit tricky. Next, the design needed to be flexible enough for a variety of spaces - vertical, horizontal and different sizes. And lastly, some physical locations don’t have easy access to electrical power. So, there is an option for a solar powered irrigation system.

Because the plants are always sitting in water, this is called a Deep Water Culture (or DWC) system. One nice parts about this design is that the water does not need to pumped through the system 100% of the time. This makes a solar powered system feasible at a reasonable (about $225) cost. Also, if there is a temporary power outage, the plants will be fine for several days.

How to build your own DWC system.

Solar powered system at a local community garden

A-Frame System (Home made)

This 75 plant unit measure about 5 x 5 and was created for Maker Faire 2016 and 2017 in San Mateo. When the system is in full production in the summer, you can harvest 2 heads of lettuce per day! It was inspired by this YouTube video (https://youtu.be/EJjAWF2DfWY), but I made some modifications to make it a bit easier to build and smaller in size. It can be built for about $200 in parts over a weekend. Most of these parts can be bought at your local hardware store, although some are probably easier/cheaper to source online.

How to build your own A-Frame instructions.

Amazon or eBay Pipe System

Instead of building your own homemade system, you can purchase a similar system on Amazon or eBay. Just search for “hydroponic pipe system”.  These systems can typically be purchased for around $100. I wanted to try one of these systems and I had good results.

The pipes are smaller than the 3” ones used on the homemade systems and are in metric sizes so you can’t go to a local store to replace/expand the system.  Also, the net cups are half the size and you will only be able to grow about half as many plants as advertised because the spacing is too tight to grow full heads of lettuce.

Nonetheless, this may be a great starter system or option for someone that wants to purcahse a ready-to-use system.

Vertical Tower System

This vertical system allows you to have a very high density of plants in a very small space. Each tower can hold 32 to 48 plants! Technically, this is an aeroponic system since the roots sit in air and the water drips down the tower to touch each plant. I purchased this system from an overseas company I found on Alibaba. It is similar in design to the Tower Garden, but much less expensive. The bad part is that Alibaba is really not set up to sell to consumers in the US. The quality of these products is so-so. I stopped using these towers because I experienced leaks along the seams that resulted in lots of algae growth on the outside of the towers.

ZipGrow Tower System

This is a different type of vertical system. ZipGrow towers. In these systems the plants are in mesh-like polyester material, similar to filter media, that lets air and water contact the roots. The density of plants is much lower than my other vertical system, but plants do grow well in the ZipGrow towers – especially basil. One downside is that towers cost about $65 each (plus shipping).

Ebb & Flow Peppers

Peppers are a great plant to grow with hydroponics. The method I use is to grow the plants in large rock wool cubes - either 4” or 6”. The irrigation method is called ebb & flow or flood & drain. Basically, the plants cubes are in a large tray, and once or twice a day you flood the trays with nutrient water. There are two openings in the tray - one where the water fills the tray and another as an overflow drain. Use a basic timer to control the times. And easy and productive way to grow all sorts of peppers.

AutoPots

AutoPots are a completely different type of system. For larger plants with a deeper root system, the other hydroponic systems are not appropriate. I use AutoPots for tomatoes, peppers, cucumbers and more. The plants grow in a soil-like material – I use a mixture of coco (coconut husks) and Perlite. This substrate does not provide any nutrition to the plants. All of the nutrition comes from the enriched water.

Each AutoPot contains a small float valve to control the level of water in each plant tray. The water with nutrients is held in a large tank. As each plant uses more water, it draws water from the tray using a capillary effect. When enough water is consumed, the float valve opens fills the tray.

The great part of the AutoPot system is that the plants are watered/fed automatically. And no power is required. You just need to fill up the tank with water and nutrients every week or so. I’ve had great luck with the system growing lots of tomatoes, peppers and cucumbers.