Growing hydroponic tomatoes – Part One

Growing hydroponically means you can control most of external conditions influencing your crop. Primarily, the controlled environment lets you achieve maximum crop-yield, crop production in the absence of suitable soil and the ability to ignore ambient temperature and seasons. Water is used more efficiently and one can grow more than soil-based growers using the same land area.

Contrary to perceptions of undernourished hydroponic tomatoes that grow in less than favorable conditions without adequate light and with no flavor, hydroponic tomatoes taste as good as the next tomato. The hydroponic tomato is isolated from the soil and hence safe from soil-based pests, crop-diseases and salinity. The tomato is also a product with high economic value, so it makes sense to produce it using the best systems, i.e. hydroponics systems. Tomatoes are easy to grow whether you are using indoor or outdoor hydroponics gardening systems, but you have to take care of their specific nutritional and environmental needs. Here are some factors that could make or break your hydroponic tomatoes!

Tomatoes need a moderate temperature range to grow optimally. High temperatures are easier to handle, but not above 93 degrees F. The ideal range is 55 to 85 degrees F and frost or prolonged cold is a simply a no-no. Exposure to strong light for at least five hours a day is a must. Nutrients need to be easily absorbed and should be rich in nitrogen. Tomatoes totally respond to pollination. Unless you want to artificially pollinate your plants, you must make them available to natural pollinators, which means turning them over to insects and wind. But most greenhouses and indoor spaces obviously can’t use natural pollinators, so you have stick with the artificial way. Tomatoes suffer in the wind and in polluted air. Don’t overwater them, but make sure you give them adequate water. Too much or too little doesn’t work here.

One can grow hydroponic tomatoes from seedlings, transplants or seed. Seedlings or transplants are the easiest, but seed provides more customised solutions as there are more varieties of tomato available to you, that are not produced as commercial seedlings or transplants. Seed growing has another advantage; it’s less expensive as you can plant scores of seeds and select the best sprouts. And this will still cost less than buying a few dozen seedlings or transplants. Advanced Nutrients is a good place to look for hydroponics plant nutrient solutions that which are organic or synthetic; their products, like No Shock or Jump Start for example, aid plant growth in the crucial first few weeks after sowing.

Once you know your tomatoes, you can start practising specialised techniques that will make your seed-grown crops a success. Like pre-germination, for instance. Here, you place seeds on a dampened paper towel in a covered container and keep this container in a warm and dark place. Peat pots or rockwool cubes can also be used to pre-germinate seeds. Your seeds should sprout within 5-7 days. If they are on a paper towel, replant them into peat pots, rockwool cubes/slabs, soil or other media. This should be done only after the seeds have sprouted to show a white “rootlet” that’s about half an inch long. Growers who intend to grow their seedlings in soil usually use an early root zone mixture which is lighter and more aerated than regular root zone media. This allows young plants to navigate the media with their delicate, beginning root systems.

Dissolved Solids in Water (TDS)

The dissolved solids in water can cause problems in your garden. Pure water is often not available for hydroponic growers. Usual salt imbalances can be kept in check with a PH correction program. But there’s a limit.

Already existing salts and other solids can combine with elements in the nutrient solution and create havoc in your garden. Water containing more than 50 parts per million (ppm) of calcium and magnesium can create serious problems. Other common elements that may be present in hard water include various carbonates, sulphur, sodium, iron and boron.

You must make a thorough scientific analysis of the water you will be using and if the results are not very good install a reverse osmosis filter system, de-ionisation system or use pure water without any added minerals.

It is critical that the nutrient solution not exceed the plant's tolerance for dissolved salts. That tolerance can vary for every crop. Unless you know the specific tolerance of a given crop, it is best to use a nutrient between 800 and 1,200 ppm. When in doubt, remember – Less is More.

Not all salts give equal ‘conductivity’ and may be misread as ‘weak’ or ‘strong’ though they may not be so. Be aware that a nutrient may be stronger than what it appears to be. Always pay attention to manufacturer’s recommendations for mixing nutrients and measure the resultant ppm (though the actual ppm may vary due to nature of the salt).

Weather has an impact on the intake of nutrients and transpiration of water by plants. In hot, dry regions the ppm may rise and the opposite holds true in cool, humid environments. At the same time, a fast growing crop can take in a huge quantity of nutrients. In such case, if your reservoir is small, you’d better change the solution frequently to avoid slow, spindly growth and plants that look sick. Some plants that are light feeders will intake nutrients slowly.

Different types of plants have differing nutrient needs. All plants may need similar nutrients. But the ratios in which they are required can differ greatly for various plants. The growth stage of the plant impacts its nutrient requirement greatly. During rapid vegetative growth and structure building, a plant needs a lot more nitrogen. But when it is flowering or developing fruits, requirements of phosphorous and magnesium may peak. That’s what gives hydroponic growers an edge over soil growers –ability to manipulate nutrient concentrations for enhanced growth.

Nutrient formulations that have the same NPK combination throughout the plant’s growth cycle do not do justice to your plant’s needs. Some nutrient formulas may be developed for a particular plant only eg: tomato, orchid, etc. It is best to use a multi-stage nutrient that allows you to adjust the total ppm and NPK ratios according to the requirement of the plant to gain full advantage and maximum profits from your hydroponic garden.