Note: This description of hydroponic tomato gardening is the continuation of a long narrative, which I've broken into several pages. Click here if you'd like to go to the beginning.
The great advantage of growing a crop hydroponically is that you have precise control over the minerals and nutrients that are fed to your plants.
You can fine-tune the nutrients that your plants are getting with far more accuracy than when growing them in the soil.
That ability to precisely control the nutrients your plants receive is how you'll achieve the maximum of quantity and quality from your plants.
But that wonderful benefit of hydroponics can also be a bit of a two-edged sword.
Since your plants will receive only the nutrients that you feed to them, it's crucial that you give your plants a balanced diet. Make a mistake with your nutrient formulation, and your plants will suffer.
Even a small mistake can be costly.
And since tomato plants require 16 different micronutrients and macronutrients, it's easy to make a mistake when mixing your nutrients from scratch.
Fortunately, though, there are formulations available which come pre-mixed. So you don't have to measure and mix 16 different elements when you're mixing nutrients (unless you prefer to do it that way - and some growers do).
That means, of course, that you also don't have to shop for, buy, and store 16 different ingredients.
For my large tomato greenhouse I buy a nutrient mix designed for hydroponic tomatoes. I use this mix in combo with three other chemicals: calcium nitrate, calcium chloride, and magnesium sulfate. So I have 4 ingredients to measure each time I mix nutrients, instead of 16.
With a hydroponic system, every time you water your tomato plants, you'll also be feeding them. Usually that's accomplished in one of two ways:
1) A nutrient concentrate is injected into the irrigation water using water-activated mechanical injectors.
2) The nutrient is mixed with a large container of water, which is used as the source of each irrigation cycle.
I've used each method in my tomato greenhouse.
The injector method is the easiest and possibly the most accurate method. Using this method requires mixing the nutrient concentrate only once a week or so. But it does require daily monitoring to assure that the injectors are working properly.
The second method - which we'll call the 'bulk tank' method - requires measuring and mixing nutrients more frequently - at least for a large-scale operation. But the bulk tank method is probably the best method for small, hobby operations. That's because a small hobby operation would need much less volume.
Where I might go through 500 gallons a day of nutrient solution, a hobby operation might need only 5 gallons.
And the bulk tank method is the more economical option, too, because quality injectors are quite expensive!
Most hydroponic tomato operations use a timer of some sort to manage irrigation cycles.
You can buy timers that initiate irrigation cycles based upon a preset time interval. But you can also buy timers that initiate irrigation cycles based upon the amount of sunlight the plants have received.
When tomatoes are grown hydroponically, they need to be watered and fed frequently. Plan on being able to deliver at least 12 irrigation cycles per day.
We use spray stakes to deliver the irrigation water - one spray stake in each Bato bucket.
There's another hydroponic technique sometimes used for tomatoes called the Nutrient Film Technique (NFT).
Using NFT, the tomato roots grow in tubes through which a very shallow layer - or film - of water continuously circulates. No perlite or other form of growing medium is used. I've read of numerous problems in growing tomatoes using this method; I've never tried it myself.
I know that NFT works great for growing hydroponic lettuce, though!
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Watering length and frequency for hydroponic tomatoes
I've built a small bato bucket system in a room with 3 tomato plants. You said at least 12 irrigation cycles per day. Would that include lights out time? …
Plain old gardener - a question about hydroponics Not rated yet
I am just finishing up the installation of a small hydroponic system. I have 7 bato buckets for tomatoes and three rail systems for lettuce. I don't …