In the indoor gardening industry, there is an ongoing debate about flushing the growing medium. Some gardeners claim that flushing the plant roots with copious amounts of fresh water removes the “chemical taste” from fruits and vegetables, and it should be a standard gardening practice. Others claim that arbitrary flushing is unnecessary, and it disturbs the natural balance of nutrients at the root zone. Some even suggest that flushing steers the plants to become more vegetative, right at the time when the plant’s energy should be directed towards fruiting and flowering. So to flush or not to flush, that is the question!
Personally, I fall into the “spoon-feeding” camp, giving the plant exactly what it needs when it needs it. By spoon-feeding, no fertilizer salts ever build up to toxic levels in the growing medium, and there is no need for flushing. If all of the essential elements are provided in the perfect balance at each stage of plant growth, flavors and aromas develop naturally, and the roots and fruits remain actively growing all the way to harvest. But if gardeners over-fertilize their plants and even one element builds up to toxic levels, flushing is the cure.
Nitrate-nitrogen is often overused in indoor gardening, especially in hydroponics. Nitrate is a luxury element. In other words, when given excess nitrate-nitrogen, plants will continue to take it up whether the plant needs it or not! Some of the unneeded nitrogen is stored in the vacuoles inside plant cells, and it can reduce the quality of food. Fortunately, nitrate-nitrogen is very water soluble, and it is easily washed away from the root zone. The best practice is to limit nitrate-nitrogen and to make sure that there is at least 15-20% leachate (water flowing out of the pot) every time that you fertigate. But if nitrates build up in the growing medium, thoroughly flushing with a quarter-strength nutrient formula and yucca extracts can be very beneficial. Once excess nitrates are removed, more of the plant’s energy can be used for fruiting and flowering instead of being wasted trying to assimilate the unneeded nitrates!
Accumulation of heavy metals can also be a problem in indoor gardening. Small amounts of trace elements are essential to plant growth, but there is a narrow window between deficiencies and toxicities. Flushing is often the best first aid when serious nutrient imbalances are suspected. First flush the roots with room-temperature water and yucca extracts to remove excess nutrients; then water the roots with a medium-strength nutrient solution. If it was a nutrient deficiency, no harm done… the fresh nutrient solution will provide the missing essential element. But if the problem was a nutrient toxicity, flushing will remove the excess minerals and the fresh nutrient solution will help bring the root zone back into balance.
To completely saturate the root zone, always add yucca extracts to the water when flushing. Yucca is a natural wetting agent, and it has a mild detergent-like effect for washing excess salts from the root zone. In normal watering, paths are formed through the growing medium, and salts can build up in the dryer areas. But yucca makes the water wetter, thoroughly penetrating the entire root zone. A little yucca goes a long way. Eight ounces of powdered yucca extracts can treat up to 4000 gallons of water!
Commentaires