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260-A Primer on Hydroponic Gardening: Growing in Water 

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Hydroponic gardening is a soil-free horticulture method for raising crops both indoors and out, and it’s a lot simpler than it appears to be. To share what you need to know to get started in hydroponics, my guest this week is Master Gardener and experienced hydroponic gardener Roger Sadowski.

Roger is a native of Cleveland, Ohio, but he now lives and gardens in North Carolina, zone 8, where he enjoys the much longer growing season. He’s someone who is always trying out new ideas and new methods of growing crops. He’s been experimenting with hydroponics for the last five-plus years after meeting author and horticulturist Brie Arthur. He had watched the episode of my public television program “Growing a Greener World” with Brie on hydroponics and decided to give it a shot himself. It turned out that he and Brie didn’t live that far from each other. He contacted her, and she invited him over. They’ve been friends ever since.

 

Roger Sadowski

Roger Sadowski lives and gardens in North Carolina, where he has extensive hydroponic gardening systems. (Courtesy of Roger Sadowski)

 

From the time he was small, Roger had a garden with his father and loved being out there planting seeds and watching it grow. When he got married and bought a house, he had a small backyard and small garden — but then he retired and moved to North Carolina, where he has a half-acre backyard. Now his gardening activities could really spread out.

Hydroponics is a new and exciting way of growing for him, and it’s been a successful journey, he says. To share his excitement and experience, he’s written about hydroponic gardening for this local Master Gardener newsletter, held seminars and done speaking engagements, and has assisted several individuals who want to try hydroponics.

Root crops such as potatoes and carrots won’t work in hydroponic gardening, but crops that grow above the soil surface in traditional horticulture are candidates for hydroponic gardening.

 

hydroponic gardens

One of Roger’s hydroponic gardens at his home. (Courtesy of Roger Sadowski)

 

Before proceeding any further with our discussion on hydroponics, I want to take a moment to remind you that I have a new book coming out in September, and it’s available for pre-order now. The title is “The Vegetable Gardening Book: Your complete guide to growing an edible organic garden from seed to harvest,” and I’m very excited for you to read it. It’s chock full of insider tips and new-to-you information that will help you step up your gardening game and tackle challenges. 

What Is Hydroponic Gardening?

Hydroponic gardening is growing plants in nutrient-rich water rather than soil. 

In traditional gardening, the soil itself and supplemental fertilizer provide nutrients to plants — though using fertilizer can be unnecessary if you have really great soil. In hydroponics, fertilizer is a must because crops growing in water can’t get the nutrients they need any other way.

The Benefits of Hydroponics

Hydroponics enables gardeners to grow crops indoors, year-round. But hydroponics can also be practiced outdoors, where there are numerous other benefits to enjoy.

In hydroponic gardening, the nutrient levels of the water can be checked and adjusted right on the spot. In soil gardening, the soil must be sent to a lab, and it can be weeks before results come back. 

To adjust nutrient levels in soil gardening, gardeners add soil amendments and then test again to know if the amendments worked to bring the nutrient level into line. But when hydroponic gardeners adjust the nutrient levels, they know right away if the nutrient level they are seeking was achieved. 

In soil gardening, water percolates down through the soil, runs off and evaporates, and plants transpire the moisture that they have taken up. Hydroponic gardening systems, for the most part, recycle water. 

Hydroponics allows more plants to be grown in a smaller area. And those plants grow more quickly because they aren’t competing with other plants in the soil for the same nutrients. 

 

hydroponic lettuce

Hydroponic lettuce can grow much faster than soil-grown lettuce because it gets a steady stream of nutrients in oxygenated water.
(Courtesy of Roger Sadowski)

 

One of Roger’s favorite things about hydroponic gardening is there is no weeding involved. And when hydroponic gardening is conducted indoors in a controlled environment, there are virtually no pest and disease issues. Even outdoor hydroponic gardening systems experience minimal occurrences of diseases — though pathogens like tomato blight that are carried in the wind can still be an issue.

According to Roger, hydroponically grown vegetables also taste better, which he attributed to having the ability to tailor the nutrients to the specific crops. 

Hydroponics can also deliver a greater harvest: Last season Roger grew eight tomato plants and yielded around 350 pounds of tomatoes. 

 

Hydroponic lettuce

Hydroponic lettuce a month later. Look how much it’s grown!
(Courtesy of Roger Sadowski)

 

How Much Does It Cost to Start a Hydroponic Gardening System

There are readily available videos and guides online that will show you how to get started in hydroponic gardening for as little as $100 — if not less. You can grow lettuce and herbs hydroponically without breaking the bank in this kind of starter system. 

To get into the more extensive, more complicated hydroponic systems that are used for crops like tomatoes and peppers, the costs begin to add up. “If you went out and bought all of these products, it would be pretty expensive,” Roger says. His advice is to start with an inexpensive system, and if you like it, then build upon that. 

How Much Work Does It Take to Have a Hydroponic Gardening System?

If you have a hydroponic garden, you can’t just set it and forget it. Roger checks the nutrient levels in his system every two or three days, and that’s what most hydroponic gardeners do. If it rains on his outdoor system, he needs to adjust the nutrients accordingly.

To check pH and nutrient levels, there are paper test strips that can be used, but Roger uses moderately priced meters that monitor the nutrient levels and pH.

There are liquid and powder “pH up” and “pH down” products available for hydroponic gardening. Roger finds the liquid much easier to work with; hydroponic gardeners who use powder have to mix it in water before adding it to their system. The process should only take 10 or 15 minutes.

Roger advises adding just a little bit of “pH up” or “pH down” at a time. A little goes a long way. It’s easier to keep adding a little more until you get it right than it is to go over the top and have to fix it. 

Hydroponic systems also require electricity to run the water pump and air pump, though the electric demands are not much, and timers can reduce the electric cost further.

 

hydroponic gardening system

Roger checks the nutrient levels and pH in his hydroponic gardens every two or three days.(Courtesy of Roger Sadowski)

 

The Dutch Bucket Hydroponic Gardening System

The Dutch bucket, or bato bucket, system uses a series of growing containers connected to the same water pumps. The buckets are filled with a substrate, which, in Roger’s case, is perlite. A drip line supplies the nutrient solution and a drain line returns the solution to the tank so it can recirculate. 

Rogers has two Dutch bucket systems, each with eight buckets.

Commercial grade pots or any 5-gallon buckets can be used. The plumbing is made out of PVC pipe and the drippers are made out of irrigation tubing. A plastic storage tote serves as Roger’s reservoir. A pond pump moves the water and an aquarium pump and an airstone in the tank oxygenate the water.

For his tomatoes and peppers, Roger has his pumps set to turn on for 45 minutes at 6 a.m., noon and 6 p.m. When the pumps are not on, the roots sit in perlite, which holds onto some water as well as nutrients that the roots have access to while the pumps are off. Roger reports no problems, even on 100° days. A few peppers get a little droopy but perk right up again when the pump comes back on as scheduled. 

 

How the Dutch bucket hydroponic gardening system works.

How the Dutch bucket hydroponic gardening system works.
(Courtesy of Roger Sadowski)

Nutrient Film Technique

The nutrient film technique suspends plants in tubes or channels that are on a slight decline. At one end is a dripline that feeds nutrients down the tube, and a film of the nutrients passes through the roots, where they are absorbed. At the end of the tube, the water is collected by a tank to be recycled.

The nutrient film technique requires the system to be on 24/7. It is suitable for herbs and lettuce, Roger says.

PVC pipes, vinyl rain gutters and plastic fence posts can be used as the channels or tubes.

“These systems don’t have to be like you see,” Roger says. “Your imagination can run wild with them.”

 

The nutrient film technique pumps nutrient solution down a tube or gutter. (

The nutrient film technique pumps nutrient solution down a tube or gutter. (Courtesy of Roger Sadowski)

 

Ebb And Flow

An ebb and flow hydroponic gardening system involves plants suspended in a tank. A pump turns on to flood the tank for a given amount of time, the roots absorb nutrients, and then the pump drains the tank. The cycle is repeated with the use of a timer. 

When the pump is off and the water is out of the plant tank, the roots have the opportunity to absorb oxygen. Many ebb and flow systems also use an air pump to oxygenate the water.

Roger had an ebb and flow tank that is timed for 15 minutes flooded followed by 10 minutes empty, then repeat.

Aquaponics

Aquaponics is a combination of aquaculture and hydroponics. Aquaculture is raising aquatic animals while hydroponics is about raising plants in water. 

In an aquaponics system, the water from a fish tank or a pond is pumped to plants. The water is rich in nitrates and ammonia from fish waste, which feed the plants. When the water returns to the fish tank, it is cleaner.

Aeroponics

Aeroponics was my gateway into growing food indoors, specifically the Tower Garden promoted by Stephen Ritz of the Green Bronx Machine. It uses mist jets instead of water pumps.

The Tower Garden is an upright garden with little removable pots on the side for individual plants. Nutrient solution is pumped up to the top and then drips down past the pots so the roots can absorb the nutrients. Like the ebb and flow, a Tower Garden operates on a timer.

Tower Garden is just one brand, and this idea can be found in several similar products.

Roger says another version of aeroponics can be homemade, with plants suspended in a tray, and pump jets that mist the roots with nutrient solution. This can be made for less than $100 with an ordinary storage tote and some PVC pipe.

Choosing Hydroponic Gardening Nutrients

Hydroponics nutrients are available in powder/granule form and liquid form. Roger prefers the powder/granule form, which comes in three parts: fertilizer, calcium nitrate and magnesium sulfate. Each is mixed separately in buckets, then mixed together and added to the reservoir. 

“A lot of the different vegetables have different nutrient requirements,” Roger points out. Lettuce won’t need as many nutrients as tomatoes and peppers, so it’s not a one-size-fits-all equation.

There are many liquid products to choose from. One type is added when first starting out, and another is used when buds start forming, and another when they are blooming. Roger finds this to be extra work compared to using the powders.

Roger uses organic products, though chemical products are available as well.

 

A Dutch bucket hydroponic garden.

A Dutch bucket hydroponic garden.  (Courtesy of Roger Sadowski)

 

Choosing Hydroponic Gardening Substrates

Roger’s substrate of choice is perlite, but there are quite a few options. Porous clay balls known as expanded clay aggregate are another popular option for bucket systems. They help retain moisture and oxygen and also hold the roots in place well.

Coir, made from coconuts, can also be used, but Rogers doesn’t like it because of its naturally high salt content. 

Rockwool is cubes made from slag and rocks heated and spun like cotton candy. Rockwell can be used for starting plants that will be transplanted into soil, but Roger uses it in his hydroponic system for growing lettuce. 

 

Rock wool cube

Rockwool, or mineral wool, is made out of basalt rock and chalk. It can be used as a growing medium for hydroponics. (Courtesy of Roger Sadowski)
(Courtesy of Roger Sadowski)

Water for Hydroponic Gardening

Roger says the water itself is important because it’s what carries nutrients to the plants. Not just any water will do. Commercial systems put water through huge filtration systems or use distilled water because it has a neutral pH. For a home gardener, the cost of distilled water will be prohibitive. 

Water from a reverse osmosis system is excellent for hydroponics. Well water, even after its filtered, will have impurities like magnesium. 

Tap water includes chlorine or chloramine (a combination of chlorine and ammonia) which Roger removes by letting the water sit in a drum with an airstone for a time so the chlorine will dissipate. Alternatively, ascorbic acid (vitamin C) can be added to tap water to get rid of chlorine. Activated charcoal or the bottle from the pet store of solution that’s added to fish bowls are two other ways to reduce chlorine.

Meters for Hydroponic Gardening

Roger advises staying away from cheaper meters, which often don’t give accurate results. He has a $45 pH meter and a $55 electrical conductivity meter. Both work quite well, though the pH meter does need to be calibrated from time to time, which Roger says is not that difficult.

The electrical conductivity meter, or EC meter, checks the parts per million (PPM) or total dissolved solids (TDS).

Having a good thermometer is also important. If the temperate of the nutrient solutions goes above 80°, the plants have a harder time taking up the nutrients. Roger keeps his tanks in a shady spot to keep the water from overheating or buries the tanks in the ground. He also drops frozen jugs of water into the tanks on hot days.

 

EC meter

A moderately priced electrical conductivity meter is used to monitor the nutrient levels in Roger’s hydroponic gardens.
(Courtesy of Roger Sadowski)

 

Starting Seeds for Hydroponics

Roger germinates seeds in seed-starting mix. When the seedlings are ready, he removes them from their trays, removes the soil from the roots as best he can, and dunks them in pots of water to rinse off the dirt. Then he plants the seedlings into the perlite in his hydroponic systems. Dirt can clog pumps and irrigation tubing, so it’s important to take care of it before transplanting the seedlings. Roger strains his perlite in a paint strainer for the same reason.

 

Lettuce in net pot

Net pots are used in many hydroponic gardens to allow water while containing the roots and substrate.
(Courtesy of Roger Sadowski)

 

I hope you enjoyed my conversation with Roger Sadowski. If you haven’t listened yet, you can do so now by clicking the Play button on the green bar near the top of this post.

Have you tried hydroponic gardening? Let us know your results and experience in the comments below.

Links & Resources

Some product links in this guide are affiliate links. See full disclosure below.

Episode 181: The Power of a Plant: Stephen Ritz and His Incredible Green Bronx Machine

Episode 238: Peat Moss: Examining the Challenges of Its Ongoing Use in the Face of Climate Change

Episode 256: The Challenge (and Solution) for Using Coconut Coir as a Seed Starting and Growing Medium

joegardener Online Gardening Academy™: Popular courses on gardening fundamentals; managing pests, diseases & weeds; seed starting and more.

joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.

joegardener Online Gardening Academy Master Seed Starting: Everything you need to know to start your own plants from seed — indoors and out. 

joegardener Online Gardening Academy Growing Epic Tomatoes: Learn how to grow epic tomatoes with Joe Lamp’l and Craig LeHoullier. 

joegardener Online Gardening Academy Master Pests, Diseases & Weeds: Learn the proactive steps to take to manage pests, diseases and weeds for a more successful garden with a lot less frustration. Just $47 for lifetime access!

joegardener Online Gardening Academy Perfect Soil Recipe Master Class: Learn how to create the perfect soil environment for thriving plants.

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Growing a Greener World®     

GGW Episode 205: Hydroponics

GGW Episode 813: New Ways of Growing Our Favorite Vegetables

Electrical conductivity meter

Expanded clay aggregate 

 pH meter

Reverse osmosis system

Rockwool

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Disclosure: Some product links in this guide are affiliate links, which means we get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us, and compensation is not an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, Milorganite, Soil3, Greenhouse Megastore, PittMoss, Territorial Seed Company, and TerraThrive. These companies are either Brand Partners of joegardener.com and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.

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