Minty Fresh Hydroponics

Today, we were happy to discover that both our systems were dripping consistently and the mint plants looked healthy.  However, the water levels in the gallon jugs of both systems were both significantly lower.  We remedied this by adding a half gallon of water to each system.  We also added one tablespoon of fertilizer to the system with fertilizer to ensure that the ratio of water and fertilizer was balanced.  Plants 1,3, and 4 maintained a consistent number of leaves.  Plant 6 experienced an increase in leaves and plants 2 and 5 decreased in leaves.  We will continue to monitor our systems closely.  Hopefully our plants will continue to thrive when we leave for Thanksgiving Break!

The flow rates of our two systems were drastically different. The system without the nutrients had a drip rate of 5 drips per minute, yet the one with the nutrients was 154 drops a minute. By trying to keep this variable constant, we adjusted our system. We did this by adding blue valves to the tubes, added zip ties to allow the top tube to drip directly in the middle of the bottle, and adjusted the knob on the pump. We then tested the drip rate again, and came up with more even data. The flow rate of plants 1-3 (the plants with the nutrients) was 85 drops per minute, and plants 4-6, (the plants without the nutrients) was 76 drops per minute. We now have a constant flow rate on both systems. 

In order to ensure the accuracy of our experiment which tests the effect of nutrients on mint plant growth, all other factors must be controlled. Measuring the amount of drops from the last water bottle to the gallon bottle, the flow rate of the nutrient system is 154 drops/minute while the flow rate of the non-nutrient system is 5 drops/minute. When our group comes in at the beginning of each class, the flow rate has come to a standstill. However, after we work with the pump pressure for a few minutes, the systems are up and running again. We must figure out a way to keep our two system's flow rate's consistent and the same. Otherwise, we will not be able to contribute the plant's growth to the factor of nutrients alone. In addition to counting the number of leaves each day, we will now measure the flow rate. After a few more days of recording data, we will be ready to make graphs of our data and draw some conclusions. 

Attach the hooks on window, and tie the fishing string from the top bottle in a loop to hang from the hook.

Attach the air tubes to the pump

Fill the reservoir bottle with 1 gallon of water (water should be coming out of air lift tube and into the top bottle)

If water is flowing consistently, fertilizer can be poured into the respective side (the three bottles that will be receiving Alaska Pure Kelp Plant Food)

Add zip ties to the hook so that the water bottles can reach the gallon jug.

Use tape to attach the airlift tube to the zip tie and top water bottle.

Bend the top of the air lift tube and insert into the top of the first plant holder bottle (forming a U-shape inside the bottle) The end of the tube should be pointing down.

Put plants and clay pellets into net cups (shake out any dirt on the roots to avoid dirt getting into the system)

Place 1 net cup into each water bottle upside down

Then place the net cup with the plants on top of the upside down cups in the water bottles

The plants on the system with no fertilizer (plants 4-6) were growing well and had a total gain of 4 leaves over the past 4 days.  The plants in the system with fertilizer appeared to be dying (wilted and brown) and had only gained 2 small leaves over the past 4 days.  After adjusting the flow rate and the air pump, the system with fertilizer had a very consistent flow rate and there was a constant drip of water coming from the bottom bottle.  There wasn't necessarily too much water because the plants were not turning yellow. Now we just need to improve the flow rate of the plants 4-6. 

After assembling and turning on both of our systems yesterday, we checked on them today to find that the system with the nutrients was not dripping any water and the mint plants were dead.  We replaced the dead plants with new ones and we added an extra zip tie so that the tubing was further extended into the system and we then taped the tubing to the bottles to ensure that the water would have a straight passage.  We also closed the blinds to protect the plants from extreme sun.  We also added more water to water jug of the system.

-Chloe

This is what our mint seedlings look like today!  Mint has an estimated germination period of 12 to 16 days.  Our mint has exceeded the 16 day period and although the mint has improved significantly since it was moved to the peat soil, the seedlings are looking a little fragile.  On a better note, they do not have signs of overwatering, which would consist of yellowing leaves.  Hopefully, they will start to look a little stronger as they continue to grow.

Second system built, we put the cups and soil pellets into the water bottles using two cups stacked on top of each other. Ready to plant the mint leaves soon!

After we completed the first half of our hydroponic system, we realized that the water was not dripping through the air lift pipe as effectively as we had hoped. After removing the PVC pipe and trying out a taller gallon jug, their was still no improvement. We brainstormed ways to increase the pressure and therefore increase the water's velocity. Jacquelyn brought up how you can increase the water pressure in a hose by partially covering the nozzle with your thumb. Beth suggested that we apply this reasoning to our system and utilize a thinner air lift tube to increase pressure. At first we thought that the thinner tube had decreased the pressure, but after waiting a few moments for the pressure to build, our system was working perfectly. Here is a video of our completed system! All we need to do now is wait for our plants to fully mature. 

Push the air lift tube up one of the PVC pipes

Make sure that the mouth of the air lift tube is pointing straight down

Fill up the gallon jug

Make sure that the mouth of the last plant holding bottle feeds into the mouth of the reservoir bottle.

Create a stack with the three water bottles by nesting the top mouth of the bottle into the hole cut out from the bottom of the next water bottle.

Weave fishing line through the holes at the base of the top plastic water bottle. For the second and third water bottles, put the string through holes and tie a knot so that all of the bottles are connected.

Here are the steps we all completed today!

Cut the adapter tubes (2 inches) and pump tube (already cut) and the air lift tube (4 feet).

Insert 2 small holes (for the needles) in the airlift tube (2.5 inches from the bottom) on both sides

Attach half of the adapter tube over the end of the pump tube and insert the needle into the adapter tube.

Place the needles into the air lift tube.

Use plumber's tape to wrap around the needles and any connection between tubes.

Using a saw, cut the 2 PVC pipes at 10 inches.

Place the 2 10 inch PVC pipes in the gallon jug

Use a zip tie to attach the 2 pipes to the opening of the gallon jug

1) Gather all materials

2) Use the cap of the 1.5 liter water bottle to trace a circle at the bottom center of each 1.5 liter water bottle with the sharpie.

3)  Burn a small hole in the center of each water bottle bottom using solder iron.

4) Use a plug in power drill to widen the hole.

5) Use the printed template to trace on the bottom part of the bottle below the center.

6) Use an Xacto knife to cut out the circle traced on each water bottle

7) Use the cap to trace the circle on the top shoulder of each gallon reservoir bottle with a sharpie

8) Cut out the traced circle with the Xacto knife

9) Paint the top half of the water bottles with the white acrylic paint, which will be facing downward.

10) Puncture two corresponding small holes with the tip of the soldering iron, on the bottom base of the bottle.

-Jacquelyn (photos)

Tools Used:

-Dewalt plug-in drill in order to cut a perfect circle for each water bottle

-Soldering iron in order to burn the holes on both sides of the bottom of each plastic bottle and the hole at the bottom too (originally we were to use an xActo knife, but this iron expedited the process)

-an xActo was used to cut a larger hole in the shoulder of the gallon water bottle 

Plant Progress:

The original soil (potting soil) used for our seeds was not sufficient and the mint seeds were transferred to a peat soil that is richer in nutrients, approximately 9 days ago.  The seeds should germinate in the next 3-4 days.

Next week we'll begin building this design! Still waiting on our mint seeds to germinate.

Advantages:

plants can be grown anywhere

uses 1/20th the amount of water compared to soil-based farming

doesn’t require pesticides, fertilizers, or other chemicals because there is no chance of soil-based diseases or pests.

crops grow twice as fast

creates a more controlled environment

needs 20% less space than soil-based farming

water can be reused multiple times which is more cost effective and conserves water, compared to traditional gardening which uses run-off

requires less labor

can control nutrient balance

no soil setup

vitamin content is 50% more in hydroponically grown plants

crops can be grown all year round

Disadvantages:

initial setup of hydroponics is costly

requires constant supervision

if there is a power outage, the plants will dry out

technical knowledge is needed for growing plants with hydroponics