Spinach about a week after nutrients added.

 The spinach I was growing managed to complete most of its life cycle. Around a week after my last post I added the nutrient solution to the plants’ water, thats when they really started to take off.  I had one hiccup during the test run where I didn’t properly sent the flow rate of one the IV bags and half the nutrient solution was lost. If I was a little less… well lazy that day… I would have replaced it , but I didn’t.  So the IV bag ran out of nutrient solution and some of the plants died before they reached maturity.  Luckily, the rest of the plants managed to reach their flowering stage.  So overall, the IV bags were incredible useful. Thanks Jordan for the idea!

 Seeing how classes are starting to pick up, I figure now is a good time to stop the experiment and take some time to look over my notes.  But, I hope to have another prototype built by the end of next month. ( Btw, sorry for not being around open house lately to discuss hydroponics, I have a night class that meets at the same time this semester).

Speaking of which, a friend of mine who frequently stops by open house, Ian, has taken the plans of the hydroponic garden I built two years ago and built one of his own at home.  Suffice to say, the plants have grown wild and are firmly in control of his bedroom. Given how successful his garden has been, he’s inspired me to dust of my old plans and think about building another, LARGER, set up for just for show (the hydro setup currently at Hive is mainly for experimentation).  That’s all for now…

Spinach reaching maturity.

New hydroponic setup… Let’s just say my carpentry skills are a little rusty.

So here is a quick update on my hydroponics setup at Hive76.  In my previous post I uploaded a video on a hydroponic garden I built in my basement two years ago.  My goal was to build the setup with as little moving parts as possible to ensure the garden required little maintenance.  With the hydroponic garden I am building at Hive76 I decided to keep to the spirit of simplicity but a completely different approach with it.

With my latest version I am using medical grade IV bags to store the water above the plants.  Then by attaching a mechanism to the IV bags known as a ‘flow controller’, gravity pulls the water from the bags to the plants below at a consistent rate.  The rate at which water flows through that controller be anywhere from 5 to 250 ml / hr.

The IV bags and flow controllers are great because they are very inexpensive (one IV bag and flow controller cost me a few dollars from medtecmedical.com).  Plus they can potentially be reused since they are being used on plants and not humans if you are careful to prevent contamination. But possible the most useful thing about using IV bags is that they require no energy to operate, which further reduces costs.

IV bags filled with water.

To evenly distribute the water that is supplied by the IV bags to the plants, I put the plants within a medium of rockwool cubes that are about 1 cubic centimeter in size.  The rockwool essentially acts as a sponge that takes the water that is supplied by the IV drip and evenly distributes it to all the plants within the container.

I’m testing my current hydroponic setup on spinach seeds at the moment.  The plants are still in their infancy so I have not added nutrients to their water supply yet but I plan to do so in about a week(adding too high a concentration of nutrients to young plants can damage their roots).  My short term goal is to monitor the spinach in my hydroponic setup through its entire life cycle, taking general notes along the way.  After the plants have finished their life cycle I want to take some time to build a second prototype and post its plans on Hive’s webpage. Hopefully by that point, the system will be a useful platform for scientific experimentation. Then the real fun can begin!!!

Gravity flow controller: controls the flow rate of liquid from the IV bags.

Germinating seed in rockwool and temperature probe.

Hydroponics has the potential to revolutionize farming as we know it because it allows for plants to be grown in highly controlled environments.  This means that the light, water, and nutrients that plants need to thrive can be optimized to promote rapid growth while reducing waste and pollution.   Also, as mentioned before, hydroponics systems be built vertically instead of just horizontally, which is a huge benefit in dense urban environments like Philadelphia.

Even with all the potential benefits of hydroponics, it has yet to become a competitor with traditional farming in the open market.  There are many reasons for this, one reason is that the cost of lighting in an indoor hydroponic system will always cost more than traditional farming, which gets its light for free from the sun.  (Luckily the cost of lighting is dropping all the time with advancements in florescent bulbs and LED technology.) Another reason is that there is a lot of politics around farming that doesn’t favor the development of hydroponics.

Despite all the this, hydroponics is still holds a lot of potential to revolutionize agriculture.  It is also a great way to learn about plant science.  I’m particularly interested in using hydroponics to develop a low cost platform for amateur science experiments.   The hope is that by empowering people with the right tools , the next breakthrough in agriculture might come from a high-school student’s science fair project!

The hydroponic system that I am building at Hive76 is very much in the early stages. In the meantime, I wanted to post a video on a previous hydroponic system that I built in my basement 2 years ago.   It works by flooding the roots of the plants with water supplied by a reservoir below.

Enjoy and stay tuned for updates!

Added bonus: these easy-to-make products can be re-created on your own to be used as gifts for the upcoming holiday season!!

All Natural Handmade Personal Care Products Class

Click Here to Get Tickets

Sunday, December 2, 2012, 12:00PM – 2:30PM

Hive76, 915 Spring Garden St, Philadelphia, PA 19123

$25 (includes all materials…but feel free to bring your own essential oil if you have a specific signature scent!)

Double-acting PVC hydraulic cylinder and control valve

The pressure in your typical garden hose is nominally around 40 psi or so, so my first hydraulic cylinder should be able to develop about 125 pounds of force if it had really good seals. This is a proof of concept so I didn’t bother with o-rings or anything, so it leaks like crazy and thus is unable to develop quite those kinds of pressures, although it is quite strong. Moving from a 2″ to a 3″ hydraulic cylinder would bring this up to about 282 pounds of force, not too shabby for garden hose power!

The hydraulic cylinder is made of standard PVC pipe (2″ for the cylinder and 1.5″ for the ram), although I had to use my lathe to turn down a 1.5″ pipe cap to fit inside the outer cylinder. The control valve is made of 1/2″ CPVC fittings and tubing, with the exception of the spool which is a length of 1/2″ solid PVC rod. I had to turn down the spool on my lathe to the appropriate profile and also had to drill out the valve to fit it. The fit is fairly poor but it shows that the concept definitely works. Eventually I am hoping to be able to have all the custom parts injection molded to get the unit cost down cheap enough that it would make a good toy for DIY doodlers and budding engineers everywhere.

44x18 cellulose sheet drying on clothesline

Back in mid September, we made a batch of Bacterial Cellulose in two 44″ x 18″ tray bioreactors, using Adam Korshid’s “blanco cellulose” medium (sugar, yeast and apple-cider vinegar in ratios carefully measured by eye and tongue).  About two weeks later, one of the cultures had essentially failed, but the other had blossomed with a vengeance, coughing up a giant, off-while pellicle that was about 3/8 inches thick and probably weighing a good 10 pounds.  For what it’s worth, it was also quite a smelly beast.  In fact, the smell largely motivated the timing of the harvest (kind of a “get-that-friggin-thing-outta-here” situation).  One unexpected benefit of the stench was that I was able to identify butyric acid as the main offender — so the absence tea in the culture seems to result in increased butyric acid production. Possibly a consequence of the low nitrogen content of the “blanco” medium?  It might be interesting to research the topic …

At any rate, the 44×18 sheet was ultimately dried and delivered to Ann Saintpeter as promised.  We’ll see what she prints on it, if anything.  While the sheet was drying, I discovered that you could kill the smell by dusting it with baking soda.  It also turns out I was late to that particular party — apparently baking soda is renown as an odor killer precisely because it forms salts with organic acids that tend to be some of the main components of many unpleasant odors.

The sheet ultimately dried to look very much like a giant, soft tortilla, complete with a dusty surface (courtesy of the baking soda).  It also ended up with some mild scorch marks, since I was trying to dry it in a hotel room, using the courtesy hair-dryer and iron.  If nothing else, the scorch marks helped with the tortilla-like appearance.

I’m currently embarking on a little experiment to study factors influencing cellulose production, including density of the substrate (i.e. how much sugar to hit the production “sweet spot”, so to speak) and substrate type (supposedly glycerin is the ultimate feed-stock).  If there are any results worth publishing, we will do so — possibly with hardcopies on microbial cellulose paper.

Microbial "paper" formed by peeling a layer from a kombucha "pellicle" (a.k.a. SCOBY)

Microbial cellulose is unlike any material I have ever handled, and it has some remarkable properties.  It is almost pure cellulose — no lignin, no hemi-cellulose etc., so, unlike plant-derived cellulose, you can grow it and use it in its raw form with no chemical processing.  The cellulose molecules are unusually long in comparison to plant-derived cellulose, and the fibrils that the Aceteobacter Xylinum bacteria produce are arranged as stacks of microporous, web-like membranes.  As a result, the material has a surprising strength to weight ratio and endures repeated folding without apparent weakening.  It feels like parchment, but it is extremely hydrophylic and can hold 100x its dry weight in water.  The fact that it is a naturally occurring  hydrogel makes it a great raw material for aerogels and the like, and the fact that it is organized as layers of microporous membranes makes it a good candidate for various kinds of semi-permeable barriers.

To me, it seems like the ultimate green material — no fertilizers, no machinery, little or no post-processing, strong, biodegradable and just generally useful for all sorts of interesting of applications.  Plus, it can be made from waste sugar and can ultimately be recycled by inclusion in paper, or by breaking the cellulose down into sugar and making new cellulose.  What’s not to love?

Cellulose culture using iced tea mix, yeast and water

Anyone can make this stuff.  All you need is a kombucha “mother”, some yeast, some sugary medium and a container in which to grow the stuff.  Here’s a picture of a five gallon bucket that I filled with instant iced tea mix, a packet of yeast and five gallons of water.  I tossed in some fragments from a kombucha mother, poured the  whole shootin’-kaboodle into a shallow tray and within a week, I had a  four square foot mat of cellulose that looked like this:

Microbial cellulose raised in culture of instant iced tea mix

A cellulose culture grown in sugar water and vinegar

Of, course, the iced tea mix was a mistake — the artificial color made the resulting cellulose incredibly gross looking.  It literally looked like someone had vomited their guts up, with the cellulose gel mat playing the role of “giant expelled stomach”.

As a parallel experiment, I raised some cellulose in a culture of sugar water, vinegar and yeast.  This made almost pure white cellulose that cleaned up nicely.  The yield of this “vinegar and sugar” batch seemed slightly lower than the “instant iced tea” batch, but the improved aesthetics may be worth the reduced yield.

I am planning to use the material in a number of ways — I converted the iced tea cellulose into shredded cellulose gel and then dried it in methanol, with the intent of using the fibers to make strong, biodegradable composites.  I also intend to use the sheets for composites and I plan to make some thick structures in order to see if I can convert them to cellulose aerogel.

Sheet of sugar-water & vinegar raised cellulose after quick rinse