It all started with an outside garden in 3 raised beds. Each bed was 4 feet wide and measured between 8 and 20 feet long. I built these raised beds 8 years ago. In the first 2 years I had a great return on my work investment. I grew tomatoes, cucumbers, peas and green onions just to name a few. But as the years went on I started to see smaller plants with more and more disease problems. Even after using fertilizer and balancing the PH of the soil, I could not recreate my original first few years of vitality. I was very discouraged at how much work it took and how little we received through the year. I was never very good with weeding the garden and watering it was always a chore. As our family grew I had less and less time to dedicate to our garden. When we took vacations, the garden suffered with automated watering systems that would fail and damaged plants for the year.
With this in mind I started to get into hydroponics. I knew the technique existed and had always thought that it was something for huge industrial farms that used special equipment. It is true that there is different equipment involved than a traditional garden but this is not something you need to invest a large sum for or dedicate all your free time to. For me this was an answer to fix the less than satisfactory results I have had with raised beds and it was something that always interested me.
In retrospect I am not sure what really drove me to this but as the saying goes, sometimes its not about the destination but about the journey.
I have to say that before building this hydroponics garden, I had to do a lot of research from various sources. I did not write down where I found most of these answers so I will add all the credits I can remember. If you feel I missed something please let me know and I will be happy to make a link back to the original ideas. I found http://www.goodshomedesign.com/how-to-grow-168-plants-in-a-6-x-10-space-with-a-diy-a-frame-hydroponic-system/ particularly useful in the use of uniseals and the general design.
The design starts at the reservoir. There are several things in the 30 gallon tote.
- Nutrient rich water.
- The water in the system is taken directly from our pressure tank in the house.
- About 300 PPM of calcium and magnesium is in our well water.
- pH of about 5 to 6 . (slightly basic is not the ideal pH for growing most vegetables, keep reading to learn how to drive the pH down if you have basic water)
- I used General Hydroponics Maxi Series for nutrients.(grow and bloom).
- Followed the feeding charts for the nutrients.
- This reservoir was changed about every 2 weeks.
- submersible water pump (runs 24x7)
- air stones connected to an air pump. (runs 24x7)
- Float valve connected to the water supply. This keeps the water level full as plants pull water from the system.
Each tube is suspended with J hooks. These hooks allow you to hang the bottom pipe then use the length of the hook to easily get the correct height of the next line. The spacing works out as well.
Each pipe has a hole drilled for net cups between 12 and 18 inches apart. Different distances are appropriate for different plants. Follow the directions on the seed packets to find out how much distance is needed between plants. It looks really skimpy and a waste of space in the beginning but as the plants grow, cramming them too close together makes them stretch for space and then fall over and break.
In the net cups I used clay pebbles to help keep the plants upright.
As for the actual plants I grew basil, broccoli, tomatoes, peppers, rainbow chard, kale, cayenne peppers, zucchini and cucumbers. Most of these plants were started from seed in small peat disks. As it came time to transfer the seedlings to the a frame, I washed out as much of the peat as possible from the roots and placed the bare plant in the clay pebbles. Some of the tomato and pepper plants were quite large and were started in potting soil. This beginning method was easier to wash off but left me picking out bits of soil from the filter for a few weeks as I could not get all of it out of the roots. I used a 5 gallon bucket of water to wash the roots, taking care not to be forceful. I took my time with a dunking/ light water flow technique and was able to get most of the dirt off. When I planted these larger plants I could only fit a limited number of pebbles in the cup. However there was enough pebbles to lock together in order to allow the roots to grow in the water and establish a good base for the plant. I think transferring these larger plants stressed them out a bit. It took 2 weeks after planting to see them stop wilting and to show new growth. I knew they were a bit large to do this but I couldn't plant them any earlier as I needed the time to finish the frame construction.
Every night I also monitored the pH. As plants use nutrients in the water the pH changes. Different elements are only accessible to the plant at certain pH levels. It takes a variation between 5 and 7 to cover the needs of the plants as they grow. I tried citric acid and vinegar to drive down the pH from my water level of 7.5. The problem with these acidic liquids is that they break down quickly and the pH goes right back up. This was not sustainable for a 24 or even a 48 hour period. I finally found that sulfuric acid did the trick. It's available at any hardware or auto parts store. Its relatively cheap and a little goes a long way. It comes in a 30% solution of acid to water. This was way to strong to add it to the garden as is. I read that I could dilute it down to between 3% and 5% by mixing it with reverse osmosis water. I started mixing 100ml of the 30% solution and 700ml of reverse osmosis water in a ball jar. I realize the ml markings on the jar are horribly inaccurate, but it seemed to be good enough in this situation. After some trial and error, I was able to decipher how much of this acid solution to put in my garden to give me my desired pH. I finally found that adding 100ml of the 3% to 5% solution would bring pH down 1 point. That's 250ml of solution per night. I found this amount worked for me but based on how much water is in the system it will vary. It also mattered where I was in the cycle of reservoir changes because plants consume nutrients at different rates and these left over nutrients affect pH in different ways. I read that such dramatic swings in pH was bad for plant health, but this is something that I could only solve by some expensive sensors, computer and dosing pumps. For me it was worth the risk just adding the acid when I could. A word of CAUTION: Sulfuric acid WILL BURN YOU if you get it on your skin. Keep some baking soda close and wear protective gloves and goggles. I found that once diluted it was not as dangerous but still not something I wanted to touch. A second benefit to using sulfuric acid is that the plants seemed to respond well to the extra sulfur. I noticed that when I stopped using vinegar that a slime disappeared from the inside of my reservoir.
When I posed the question to my wife as to where to put our hydroponic garden she gave me the 6x10 area over the septic tank. This is how I settled on the dimensions. The spot had always been an eye sore and needed to be covered. We decided to build the entire 6 by 8 ft frame on skids, just in case we ran into a problem and we needed to access the tank. Thankfully we did not :) We also put down mulch and landscape fabric to keep the weeds from growing up.
Next to the frame I needed a reservoir for the water. This reservoir is just a 30 gallon storage bin from Costco. I think it cost me $6 to $8. I wanted to keep the water cool so I dug a hole in the ground and made sure the top of the reservoir was 2 inches above the ground to keep any rainwater out. You can also see in this picture the plywood cover for the reservoir. This cover was done to keep the sun from heating up the water.
I decided to orientate the system with the plants facing east and west. The north is left and south is right of this picture. The reason for this orientation was to allow plants on either side of the A frame equal access to the sun. This area receives a lot of sun and I new that even though most plants like full sun, too much could be a problem. The A frame is out of the shadow of the house around 10 am and the west side (facing us in this picture) stays in direct sun until 7pm. I thought the balance was a good choice.
Inside the reservoir is a submersible pump. It's connected to PVC piping thats 3/4 inch wide and fitted with a hose thread fitting onto the pump. In order to make the act of taking the pump out and cleaning it easier, I used a coupling on the lid. The pump I purchased can barely push water 6 feet in the air. This lower pressure made the pipe fittings easier to handle and I didn't have to pressure test anything. It did however cause some problems with balancing out the pressure so that all the pipes didn't received equal water. It's a bit undersized for this garden but it worked out ok. I will probably repurpose it next year and purchase a slightly stronger pump ( maybe one that can push water 10 feet in the air).
The other item pictured in the photo above is the float valve. It's typically used for a reverse osmosis tank system but for the low price of $5 from amazon it was an easy choice. I had seen others use the float from a toilet but that was more complicated and costly. The 1/4 inch feeder line is connected directly to the well pressure tank for the purpose of keeping the reservoir topped off.
This is a homemade gravity filter. I could not find anything that I liked that was pre made at the price I needed. I initially had problems with my valves becoming clogged up with any bits of roots or debris that worked itself into the system. I built this out of some screen and a piece of 4inch pipe. The feed goes in from the side and is connected to a pipe inside the end about 1 inch from the bottom. In the middle there are simple screens to catch any debris. At the top there is the exit pipe. This exit pipe is below the top about 2 inches. It's the same idea as a septic tank. Good clean water is in the middle of the pipe. Solids fall to the bottom, any debris gets stuck in the screen and if anything floats it gets stuck in the top. The bottom of the pipe is a simple screw pressure test plug.
This shows some of the material that was filtered out. The material consists mostly of bits of roots and calcium from our water supply. I even found seeds from trees sprouting in there! If you think about it we are creating the perfect environment for plants to grow. we are growing not only the plants we want but also anything that gets into the system. Seeds are particularly problematic because they get caught in filters and start to send out roots. These roots get stuck in pumps and valves causing blocked water flow. Once water flow stops, oxygen levels drop and anaerobic bacteria start to thrive. This bacteria causes a foul odor and can harm your roots quickly. I had this problem pop up a few times but I was able to catch it and clean out the problems before it did permanent damage.
Here is the pump after 2 weeks of use. Its covered in calcium deposits. The easy solution to this is to take it out and soak it in vinegar for a few hours. After the soak the calcium wipes right off and the vinegar does not hurt the submersible pump.
Here you can see the drain pipes from each 4 inch plant pipe. They are able to be adjusted using uniseals. These seals work pretty well for easily sealing a bulkhead and allowing a pipe through. The trouble with them is that they are really tight and it takes a significant amount of force to adjust the pipe. I found out that using dish soap on the pipe makes this movement much easier and does not harm the plants like oil can.
The drain pipes should be adjustable because you need to raise and lower the water level as the plants mature. Each of the plants are in their little cups, each cup sits 2 inches into the 4 inch diameter pipe. You want enough water in your pipes so that the water is touching the roots when you initially put your seedlings in the system. As spring turns to summer the roots grow and they eventually get to the bottom of the pipe. At this point the plants only need a small amount of water in each tube. Adjusting these drain pipes allows you to customize each tube to the length of the roots.
I also found that some people were using aerobic bacteria to help their plants. The idea here is that you use this bacteria to break down some of the inaccessible organic compounds in the water. The roots are then able to use these broken down compounds. I decided to try this idea out using aerobic bacteria from compost tea. I used a 5 gallon bucket of water and a stocking full of compost from our compost pile. I tied that to the top of the bucket and put in air stones connected to an air pump. I then added molasses to the mix ( since bacteria thrive on sugar) and let it sit for 3 days. The result did not smell and turned the water a light brown color. I added this water into my reservoir and noticed new growth on the plants. However I have no idea if that was due to their lifecycle, weather or if it was my bacterial brew. I also noticed that when I went on vacation and had to stop adding my compost tea, there was not as much growth as I would have expected. So in my opinion the result of the bacteria was positive.
Plant roots should always look pearly white. If they are not you have a problem. Even if your roots look healthy, if you smell something rotting then its probably your roots and you have to do something fast to stop it.
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