day one of WEEK TWO: Small Growth, High pH, Add More Nutrient Solution

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:
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.


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