Month: October 2012

day one of WEEK TWO:

Before Class:
Growth: Plant is now a total of 1 and 5/8″ tall. Plant has grown a little over 3/4″ in two days!
Water Temperature: 75.1 degrees Fahrenheit
pH Level: 7.3

After Class (the changes we made to our system, if any):
Growth:
Water Temperature: 73 degrees Fahrenheit
pH Level: 5.6

Here are a few pictures of our plant’s growth:

 

 

 

 

 

 

 

 

 

Here is a bit clearer picture of our plant’s growth:

 

 

 

 

 

 

Notes and Other Thoughts:

In the last post I said I would comment on the type of lighting we are using. We are using a special grow lightbulb that is 400 Watts. It runs on a 12 hour cycle, 12 hours on, 12 hours off.

We seem to be getting very high pH levels. I did a quick search on some hydroponic blogs and also checked out a few websites from a simple google search. I had to filter out some of the material myself, but I have come to several possible theories. (1) There is a possibility that the tap water we used to mix our nutrient solution had a high pH. A pH of 7 is neutral and is somewhat ideal for tapwater, so this may be the reason. (2) In the early growing stages, plants will absorb mainly nitrates which will actually raise the pH levels. I think this too makes a lot of sense. We have seen astounding growth in just two days, and I think it is entirely possible that the plant is making use of these nitrates, which is essentially food for plants. (3) Back to the nutrient solution, if we continue to see such a high pH, I am wondering if we shouldn’t just mix a different batch of solution and pay VERY close attention to the pH. If we could dilute the solution, I imagine that we will be more satisfied with our pH level. I would really like to find an answer soon because I know that high pH levels can cause stress on a plant, and this is the last thing I want to happen to our tiny plant. It needs nutrients and comfortable conditions in order to grow big, healthy, and fully.

I’ll look into it more and keep posting!

-Dustin

It’s been a week since I have last checked up on our hydroponic system. Last Monday we planted our a few seeds of baby lettuce in the rockwool surrounded by Hydroton so that the rockwool stays in place. Once the plant develops, our goal is to transplant it into the Hydroton to allow the roots to stretch out and fully develop. We chose baby lettuce because it is fast-growing and has an early germination of about 11-14 days. That way, if a problem does occur or our system  does not perform as well as we would like it to, we have enough time to make modifications and not fall behind our classmates. As I’ve said before, this is our first time doing something like this and it is going to be a process of trial and error, mixed with a little luck. We’ve done our research and feel confident our system will produce a healthy green plant, but just in case, we are leaving ourselves a little wiggle room in case things don’t go as planned.

Our plant has been growing for about a week now and below are some observations that I’d like to keep a running record of:

day one of WEEK TWO:

Before Class:
Growth: Plant is now 3/4″ tall. Plant has grown 3/4″ since last week
Water Temperature: 72.9 degrees Fahrenheit
pH Level: 7.0

After Class:
Growth:
Water Temperature: 73 degrees Fahrenheit
pH Level: 6.4

Here are a few pictures of our plant’s growth:

 

 

 

 

 

 

 

 

 

 

It has been a whole week since we planted our seeds and we are already seeing a little bit of growth. I would have liked to see more growth than just 3/4,” but I think our nutrient solution had something to do with the lack of growth. When we checked on our plant in the beginning of class, our nutrient solution level had dropped significantly. The pant was not getting the desired amount of nutrients because the level had dropped, maybe due to evaporation? We added more solution and found that the pH was a little high for our preference. It was at a 7.0, which is neutral. However, plants prefer a slightly acidic environment, between a 5.5 and 6.5 pH, in hydroponic systems because that seems to be the prime pH that ensures higher growth rates, higher yields, and healthier plants. We added a little bit of what is called “pH Down,” which is a chemical that will bring the pH levels down. I think it is available at most pet stores where tanks and aquatic species are sold, but I am sure that it is available at any local hydroponic store or online. However, although this stuff works like magic, it takes a while to mix in and actually bring the pH down. Note to self: Don’t keep dumping in the pH Down solution in your hydroponic system. Too much of this stuff is not good! We put in 1/2 tsp. and it brought our pH level all the way down to a 3.6, which is definitely not an ideal pH level for our plants. Fearing that we may cause damage to the plant, we decided to dump out our nutrient solution, clean out the coffee container with warm tap water and soap and then we added fresh nutrient solution to our system. Dr. Brusic told us that groups in the past have tried to add pH Up and this back and forth stresses the plants out as there are just too many chemicals involved. So, here’s a word of advice: If you’re going to add ANY chemical to your system, do it in very small quantities. It is much easier to add the chemical little by little than it is to start over. We finally got our desired pH after adding new solution and a very small amount of pH down, as our solution is around 7.0 without it.

We also added more nutrient solution this time. In a weeks time, the liquid solution level had dropped significantly to where I don’t think the plant was receiving proper nutrients. I am not sure why, but my guess is that it has something to do with evaporation. Our nutrient solution is mainly water and it makes sense that some may be lost due to evaporation, but also, the plant needs that solution to thrive. I don’t think it would hurt to check up on the plant every other day, if not every day, just to make sure our solution level is at desired level where the plant can receive proper nutrients, but also not be completely submerged in it.

In my next post I will specify what lighting we are using, the intervals of when the light is on and off, and will hopefully have some pictures within the next week that continue to document our plant’s growth. I also have to start thinking about transplanting in the coming weeks, but I’ll cross that bridge when I get there.

-Dustin

Constructing Our Hydroponic System:

Bob and I decided that we wanted to make our system as simple as possible for several reasons. (1) This is our first time experimenting with hydroponic plants and we didn’t want to get too in over our heads (2) By keeping things simple, hopefully we can influence others who do not have gardening or hydroponic expertise to give it a try (3) Most of our materials are recycled materials and because of that, we not only keep cost down, but we find other uses for things like the coffee container that may otherwise be thrown away.

Here is what we have been working on the past week and a half:

Here Bob is cutting a hole in the top of the coffee container. The smaller hole is for the PVC pipe which will create that suction we need to force water up the tube and into our growing medium. The larger hole is for the yogurt container, which is where our plant and growing medium will sit. We were careful not to make the holes too big because we want a good seal for maximum suction. We also don’t want light reaching our nutrient solution to avoid algae build up.

Bob is using a 3/16” drill bit to drill holes into the yogurt container. There are cups called “net cups” available online and in local hydroponic stores, but we want to make our design as cost efficient as possible, so we chose to emulate the net cups. The idea is that the holes in the cup allow for our nutrient solution to reach the plant, but also so that he roots of the plant have somewhere to go once the plant grows in size.

Here is the PVC pipe inserted in the coffee container with a small tube connecting it to the inside of the yogurt container. This design works on the idea that air will be pumped down the tube from the capped end of the PVC. This air will reach the bottom of the tube housed in the PVC that will create a suction (assuming we have a good seal on the PVC cap and where the tube enters the cap) and this suction will force our nutrient solution up the PVC and will travel from the PVC to our yogurt container by means of the small piece of tube shown in the center of the picture. This system is a drip system.

We have been having a lot of trouble getting a nice, steady, even drip from our system. We tried all sorts of different sizes to cut the PVC, we adjusted the tube depth, and even tried different angles for the PVC, however, the drips were inconsistent and we didn’t like what we were seeing. Last class we were fortunate enough to have a hydroponics expert, Marc from Hydro-Ponics of Harrisburg, come in to give us some pointers on how to effectively grow plants in hydroponic systems. He proposed that we get rid of the PVC pipe entirely. Our system works on the principle that the solution is oxygenated by the air pump and is then pumped up a tube housed in the PVC that will travel to the yogurt container to give our plant the nutrients it needs. This is a fairly simple system, but he recommended we get rid of the PVC pipe and make it even simpler.

Our new design features a shorter length of tube running from the air pump into the coffee container. This tube will rest at the bottom of the coffee container with an air stone attached to it to oxygenate the solution. So we nixed the PVC, used less tubing, and essentially we have the same basic function that our previous design had, just with less material. The purpose of the PVC contraption was to deliver the oxygenated solution to the plant. However, our new system works a little differently in HOW it delivers the oxygenated water to the plant. Instead of a drip system, this is now what is commonly called a “deep water system” where the plant is actually submerged in the solution.

Unfortunately we only have one coffee container, which meant we only have one lid. I did what any Tech Ed. major, or what any perfectly rational human being would do, and I used duct tape to patch up the hole where the PVC used to be inserted. We also dilled more holes in our yogurt cup because Marc advised it so that we are sure that our plant receives ample nutrients and has somewhere to stretch its roots our when it comes time for that. We also drilled a hole using the same 3/16″ bit we used earlier in the bottom of the coffee container for the air hose to feed into from the air pump. We inserted the tube and then applied a cheap silicon adhesive to it to ensure that we do not have any leakage. because the tubing is bigger than 3/16″ but smaller than 1/4,” we just wiggled the 3/16″ bit around a little bit in a circular motion until we got our desired hole size in the container.

We’re ready to plant now. We just need to mix the nutrient solution, decide on what seeds we want to plant, and track down an air stone.

-Dustin

 

After conducting some research on hydroponics, Dustin and I chose to go with an air lift drip system. Near completing the construction, we began to test the air lift and came across an issue. The pump was not producing a large enough drip and the drips were inconsistent. We happened to luck out and were able to talk to talk to an expect in the field of hydroponics from the Harrisburg area. He gave us a few pointers and suggested ditching the air lift drip system. Saying that a deep water culture system would yield much better results. This was a simple and quick change over. We will post with pictures as soon we get them uploaded