For the past two summers, I have tried growing a few vegetable plants on the sunny side of my house with poor results. The young plants bought from the nursery never had enough time or warm weather to mature. This year, I decided to try something completely different: hydroponic gardening.
What is Hydroponic Gardening?
Hydroponic gardening is the growing of plants in a soilless environment. There are 6 hydroponics gardening methods:
- Ebb and Flow
- Nutrient Film Technique
- Dutch Basket (Drip System)
- Wick System
- Deep Water Culture
Ebb and Flow
Ebb and Flow uses pumps and a large water reservoir to periodically flood the plant roots with nutrients and water. An easy method is using a large plastic tote to contain the nutrient solution with the plants sitting in a deep tray on top of the lid. The nutrient solution is pumped into the tray from the reservoir below, and then is allowed to drain back into the reservoir.
Nutrient Film Technique (NFT)
NFT uses PVC pipes that have holes cut into them to house the plants. The nutrient solution is pumped from a reservoir to the top of the pipe and allowed to flow down through the pipe, wetting the roots of the plants. The pipe is set at an angle so that excess nutrient solution flows down and returns to the reservoir.
|Nutrient Film Technique at Living With the Land, Disney World, Orlando, Florida|
|Nutrient Film Technique (detail). In this photo, the nutrients are pumped to the top of the PVC|
gutters using flexible silicon tubing.
|Disney World Science Intern showing us how to they make the ebb-and-flow hydroponic system using rain gutters and rain toppers.|
Dutch Basket (Drip System)
The Dutch Basket System uses a drip system where the water is transported via plastic pipes to a series of specially designed buckets that have a drain at the bottom. The plants are set in a net basket filled with perlite or another medium. The nutrient solution is dripped into the basket, soaking the roots; the excess fluid flows out the drain at the bottom of the bucket and into a PVC pipe which transports it back to the reservoir.
|Dutch Basket System, Living With the Land, Disney World, Orlando, Florida|
|Dutch Basket System (detail). The bucket drains into the PVC pipe through a hole at the bottom of the bucket.|
Notice that the bucket is slightly indented at the bottom to accommodate the pipe.
Aeroponic systems spray nutrient solution onto the plant's roots. This method maximizes the root's exposure to oxygen and nutrients. Aeroponics is widely used in the gardening industry to propagate plants.
|The aeroponic system at Living With the Land, Disneyworld, Orland, Florida. In this photo, you see the plants transported out of the spray chamber. The plant's roots are exposed to air for a period of time and then they are brought back to the nutrient chamber, where they are sprayed again with the nutrient solution.|
The Wick System
The wick system uses a wick, such as a rope, to transport the nutrient solution from a reservoir to the plants using osmotic pressure. It works the same way as a candle wick drawing up melted wax to the flame.
Deep Water Culture
Deep Water Culture submerges the plant's roots in the nutrient solution. To aerate the roots, oxygen is bubbled into the nutrient solution using an air pump and airstone. This is the simplest hydroponic method, so I chose a Deep Water Culture System for my first hydroponics garden.
Deep Water Culture Bucket System
Deep Water Culture Materials List:
Deep Water Hydroponics is the easiest to try since it's very simple to set up with items purchased local hardware or big box store.
- 5 Gallon Bucket (black preferably). I found very cheap black 5-gallon buckets at Fleet farm. Black buckets prevent algae growing in your bucket. You can use the white buckets, but you will need to paint the outside black using acrylic paint to cut out the light entering the bucket.
- Mesh Basket. You can find them at the local nursery. I used ones specially designed for 5-gallon buckets that I found at my local hydroponics store. You can also buy them online:
|Mesh bucket that fits snugly on top of 5-gallon bucket from Amazon.com|
- Grow Medium. The recommended grow media are a light ceramic pebble called Hydrocorn, Hydroton, and Leca Clay. You can also use Perlite. I purchased a big bag of Hydrocorn from my local hydroponic supplier, Eco Garden Supply, for a great price. Local hydroponics stores are a good place to see different setups and ask lots of questions.
|Leca clay pebbles available at Amazon.com|
- 1/4" Silicon Air Tubing. You can purchase this at a local pet store in the aquarium section or online. You can use the clear tubing too, but silicon is much more durable and less prone to collapsing.
|Silicon air tubing from Amazon.com|
- An Aquarium Air Stone. You can purchase this at a local pet store in the aquarium section or online. Larger ones are better as they produce more air bubbles.
|Large air stone from Amazon.com|
- A Check Valve. A check valve is an inexpensive device that prevents water from backing up into your air pump, causing an electrical short, or worse. You can purchase at a pet store or online.
|Check Valves from Amazon.com|
- An Air Pump. You can purchase this at a local pet store in the aquarium section or online. I like the ones that have at least two outlets.
|Strong air pumps with two outlets from Amazon.com|
- PVC Fittings. You can purchase at the local hardware store. You will need a 3/4" or a 1" 90-degree hose barb.
|hose barb from Menards|
- Rubber Grommets. You can purchase at local hardware store or online. I bought mine at the local hardware store, but if you buy bulk online, you have an assortment of sizes for a great price.
Rubber grommets from Amazon.com
- 3/4" or 1" Black Flexible Tubing. Can be purchased at Lowes, Menards, or Fleetfarm. I couldn't find any at Home Depot.
|3/4" black tubing from Amazon.com|
Equipment Electric Drill
|Electric Drill from Amazon.com|
- Assorted Spade Drill Bits
|Spade drill bits from Amazon.com|
Utility knife from Amazon.com
How to Put the Deep Water Culture System Together
1. Cut two 3/4" slices on the bucket then fold down the middle portion. This gap will allow the airline tubing to pass from the inside of the bucket to the outside without pinching.
Hydroponic bucket with airline tube
2. Drill a 5/8" hole at the bottom of the bucket. Rub a little dish soap around this hole and a 3/4" rubber grommet, then install the grommet in the hole. If you have 1" PVC fittings, cut a 1.25" hole.
3. Cut a 1-foot length of black PVC tubing. If you are using 1" PVC fittings, use 1" PVC black tubing. Insert the 90-degree hose barb into one side of the tube. If it's difficult to push in, soak the end in a tap hot water for 5 minutes.
4. Then insert the hose barb in the grommet. Refer to the "Deep Water Culture System" illustration above.
5. Pour the Hydrocorn into the net basket and give it a good rinse with a garden hose to wash away any ceramic dust. Pour clean Hydrocorn into a bowl and set aside.
6. Wash plant roots. If you are using a plant from the nursery, take the plant out of the container and gently knock off as much soil from the roots. Using your garden hose, rinse away the rest of the soil.
7. Pour a little clean Hydrocorn into the mesh basket so that it cover 1/3 of the basket. Then gently place your plant into the center of the basket and slowly pour the rest of the Hydrocorn into the mesh basket. You can use a small cup to scoop up the Hydrocorn to avoid spilling it all over the floor.
8. Measure 3.5 feet of airline tubing. Insert the air stone into one end of the airline tubing and the check valve into the other end. Make sure the check valve is inserted the right way with the arrow pointing towards the air stone (which would be the direction of the air).
Then measure out enough airline tubing so that it will reach from the check valve to a plugged in air pump. You can shorten the distance from bucket to air pump using an extension cord.
|Airline tube, check valve and air pump|
9. Fill bucket 3/4 with RO or distilled water. You can also use tap water, but you will need to dechlorinate the water using aquarium water conditioners
which you can find at a pet store:
|Water dechlorinator from Amazon.com|
10. Place the mesh basket with plant into the bucket. Plug in the air pump.
Indoor Hydroponic Garden: summer tomato plant cut down after being brought indoors
When your plants are young and the roots are short, I had my water levels quite high to ensure that the tiny roots get food and water. As the roots started growing outside of the mesh basket, I dropped the water level to the bottom of the basket. Having the water line just touch the bottom of the basket allows the ceramic media to be moist but not soaked in the nutrient solution allowing the maximum amount of air around the roots.
Hydroponics Water Works
Good water quality is important to a successful hydroponic garden. RO or distilled water is recommended because it is very clean. Another important factor is the PH of the water. Plants love slightly acidic water because it allows the absorption of nutrients. In the Midwest, our water is very hard and alkaline with a PH of over 8. Plants like a PH between 5 to 6.
To measure the PH of your water, you need a PH tester that has a wide PH range. The PH test from General Hydroponics measures from 4 to 8.5.
|Ph test from Amazon.com|
To lower the PH of the water, you can use phosphoric acid or sulphuric acid. You can buy Phosphoric acid in dry form from Amazon.com called General Hydroponics PH Down. I use a liquid form purchased at a farm supply store:
|Phosphoric acid from Tractorsupply.com|
Since I only run a small number of buckets, I use a pre-mixed fertilizer from Urban Hydroponics called "Tomato Fertilizer 20-18-38". The number at the end provides the ratio of Nitrogen, Phosphorus, and Potassium (NPK). From my research, this is a good ratio for a hydroponic fertilizer. It also has the right amount of calcium and magnesium sulfate.
|Urban Hydroponics Tomato Fertilizer 20-18-36|
I've read that some hydroponic gardeners use Miracle Grow water soluble tomato fertilizer with good results with plants that are not heavy potassium feeders. Unfortunately, Miracle Grow fertilizers color water blue, so the PH test are impossible to read. Consequently, you will need to adjust the PH of your water before adding the fertilizer.
|Miracle Grow Water Soluble Tomato Plant Food from Amazon.com |
How Many Nutrients to Add?
Hydroponic gardening requires the nutrients to be at specific concentrations which can be measured by the conductivity of the water using a TDS meter. The more dissolved minerals and salts in the water, the higher the conductivity.
|TDS Meter from Amazon|
If your water is hard, like mine, you need to measure the TDS of the water before adding any nutrients. The number you measure is your baseline number where you will need to add Nutes to the level the plant requires.
There are different levels of nutrients required at different stages of the plant:
- 500-600 PPM for young plants
- 800 to 900 for maturing plants that are growing larger root and leaf systems
- 1400 to 1800 for mature plants that are producing fruit.
I haven't read definitively that hard water is bad for hydroponic gardening. Many have suggested that high calcium levels are great for growing tomatoes. My guess is that if your hydroponic garden is not flourishing in your hard water, mix it with 50% rain or RO water.
Water softened by a water softener is not recommended because the water contains too much salt which can hurt delicate plants. I'm using 50% softened tap water and 50% RO water in my nutrient solution to see if my plants will be able to tolerate a small amount of salt.
The water levels should be checked often, sometimes every day, depending on the environment. In the summer, I had to add 1/2 a gallon of water to my buckets every day.
Using Hydrogen Peroxide
3% Hydrogen peroxide is used to keep the bacteria levels down, especially if the water temperatures are very warm. I use 2 tbs. every 3 days during warm weather and 2 tbs. a week in cooler weather. I purchase my OH from Walmart for about a dollar a bottle.
Changing the Nutrient Solution
The "Nutes" need be changed every one or two weeks, depending on the size of the plant, if its providing fruits, and the temperature. If it's sunny and hot and you are growing a large squash plant, I would change 50% of the nutrient solution every week. Every 2nd week, drain the buckets by pointing the black PVC tube down so that it's horizontal or lower.
Carefully take the mesh basket with plant and place in a clean empty 5-gallon bucket so that the roots are never touching the ground. The dirty bucket is sprayed with a 1:4 bleach solution, wiped down, and rinsed very well. Refill with dechlorinated water or RO water, adjust PH, then add dried nutrients. Return plant into the now recharged and clean bucket.
My Hydroponics Garden Summer 2014
My original hydroponics garden was actually a combined deep water ebb-and-flow system. I had drilled holes and connected the buckets with 1/2" and 1" tubes so that water could flow in and out of the buckets using a large pump. I thought this would work, but it didn't because my garden is not level enough. I ended up disconnecting the water pump and just ran the buckets like a traditional deep water system.
|Day One of my first hydroponics garden. June 9th, 2014 |
|I used a large pond pump because I had multiple buckets. I made a waterproof vented box for the pump.|
|June 18th, the appearance of the first squash flower|
|June 18th, 2014. Gem squash flower.|
|July 16th, 2014. First gem squash appears!|
|Lots of tomatoes but none are turning red.|
|A good harvest of gem squash, pepper, cherry tomatoes, and heirloom zebra tomatoes.|
In total, I harvested 10 gem squash, 20 peppers, and at least 3 big metal bowls of tomatoes. I admit, it's not a the bumper crop I was expecting with all the effort and cost of setup. However, when discussing my crop results with friends who have soil gardens, I didn't fare too badly. Since it was an unusually cool summer where the temperature maxed out at 86 and only for a week or two, many soil gardens produced very little to nothing. However, the more experienced gardeners I spoke to still had a very good harvest, despite the bad weather, since they have large gardens that have full sun.
Overwintering My Summer Plants
When the weather turned cold in September, I decided to keep some of my plants in a new indoor hydroponics garden. I bought new buckets, filled them with water and nutrients, and chose which plants to save. I decided to save my cherry tomato plant, some herbs and strawberry plants that I grew in soil planters.
For this indoor garden, I'm keeping it simple.
|From the left to the right: cherry tomato plant, lemongrass, curry plant, rosemary, lavender, and strawberry.|
The buckets will have no extra holes drilled into them to accommodate an easy drainage tube. I'll have to change the water by scooping out the water using a cup and a bucket, but I'm avoiding the danger of springing a leak and all the water pouring onto my carpeted floor.
I'm keeping the nutrient solution in low concentrations (under 700 PPM) since I've just uprooted these soil-based plants. I've also cut down all the branches from the tomato plant in the hope that it will go into hibernation mode. The buckets are situated next to a west facing window on top of a sturdy train table. I haven't cut slots into the buckets yet so the silicone air tubing is pinched.
I will be updating this post every couple of weeks to let you know how my plants are faring indoors. Thanks for reading!
Indoor Hydroponics Update: October 18th, 2014
|New growth on the tomato plant! I didn't kill it!|
DIY Hydroponics Garden: Deep Water Culture
Late Night Bites: World Street Kitchen Restaurant
Fisherman's Wharf, Victoria B.C.
Tucson Gem Show 2013