Reader Inquiries

Answers by Rick Donnan

How do I manage sodium in a hydroponic solution?

Rick Donnan

Answer by Rick Donnan

Just wondering, what is the best way to lock up sodium? I’m having big sodium issues in my hydroponics. See More

Did the Hanging Gardens of Babylon really exist?

Rick Donnan

Reader Inquiries columnist Rick Donnan.

There have always been doubts as to whether the Hanging Gardens actually existed, as explained in my column of September 2006. New evidence shows that it was real, but the story had the wrong place and the wrong king. See More

How important is water quality in hydroponics?

Nutrient ManagementPart 4

What is the impact of raw water quality in hydroponics and how can this be managed? See More

What are hydroponic fertilisers?

Question
What are hydroponic fertilisers? (Nutrient management Part 3)
What is special about hydroponic fertilisers and how are they used? See More

How do I manage nutrient balance? — Part 1

Question
Nutrition is the next aspect to be covered in this series about hydroponic management fundamentals. It is the aspect that especially new and intending growers often consider to be overwhelmingly the most important aspect of hydroponics. While it is certainly very important, failure to appreciate that it is only one of numerous important aspects of hydroponic management has often led to disaster.

There have been two classic scenarios: (a) “Hydroponics is all about nutrition— hence all my problems must be nutritional.” Wrong! and (b) “I have a proven ‘magic’ nutrient formula, therefore my problems can’t be nutritional.” Wrong again!

See More

How do I manage EC (electrical conductivity)? – Part 2

I will concentrate for the next few issues on covering some of the fundamentals of hydroponics. This is the second part on how to manage EC. I have added charts to this answer to illustrate some points I made in Part 1. See More

How do I manage EC (electrical conductivity)?

Since going digital, the number of subscribers to the magazine has increased greatly. We have noticed that there has also been an increasing interest in the fundamentals of hydroponics, for example, the most popular item is now my answer to ‘How do I manage acid addition and pH rise’. Consequently, I will concentrate for the next few issues on covering some of the fundamentals of hydroponics, starting with how to manage EC. See More

Is the ancient history of hydroponics true or not?

Question
From a US “interested reader”. Is the ancient history of hydroponics true or not?

I have a strong interest in hobby hydroponics and read quite a lot. My current interest is particularly the history of hydroponics. A fan of your column told me you don’t believe that the commonly quoted examples of the ‘hanging gardens of Babylon’ and the ‘Aztec floating gardens’ were actually hydroponic. Is this so, and why not? See More

What acid should I use for pH control?

Question
From a New South Wales lettuce grower.

I once grew lettuce in the soil, but have recently bought an operating hydroponic lettuce farm. The system is a recirculating NFT (nutrient film technique) system with channels on tables. I have been given the previous owner’s fertiliser formula, which had been quite successful, and he also used phosphoric acid for pH control. I recently visited a tomato grower and he is using nitric acid, which he said had been recommended by you. Which acid should I use? See More

From a prospective Australian investor, querying how to plan a commercial hydroponic enterprise.

Answers by Rick Donnan

Answers by Rick Donnan

Question
From a prospective Australian investor, querying how to plan a commercial hydroponic enterprise.

I am part of a syndicate of investors that is interested to set up a hydroponic business. What we require is information about the ongoing costs of running a hydroponic greenhouse and the volume of produce that can be grown. See More

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