LEGUMES AND NITROGEN FIXATION
Nitrogen fixation by legume plants occurs when symbiotic bacteria known as Rhizobia colonize the root system and take up residence within visible root nodules . These bacteria can absorb nitrogen gas ( N 2 ) from the air and convert it into ammonia ( NH 3 ) to be used by the plant . In return , the bacteria receive a carbohydrate food supply from the plant . The bacteria ’ s contribution is particularly useful for crops where nitrogen may be limiting in the soil or growing medium as it provides a source of free nitrogen fertilizer . In a well-fed hydroponic crop where we can supply plentiful nitrogen in a highly soluble and immediately available form , the use of nitrogen fixation may not seem to be that beneficial . However , with the increasing interest in organic nutrients and hydro-organic systems , nitrogen-fixing crops do have a major advantage . Organic nutrients and systems often experience issues with nitrogen nutrition , as plants have a high requirement for this element and can deplete it from organic solutions and systems very rapidly under rapid growth conditions . Nitrogen availability is dependant on the rate of microbial conversion of organic materials to plant-available forms of nitrogen , and this may not keep pace with high-density , vigorous plant growth . Even though there is no soil present to act as a plentiful source of inoculum in hydroponics , Rhizobia symbiosis does often occur naturally . To speed up the process , plants can be inoculated with the correct species of nitrogen-fixing bacteria . These are widely available as microbial products or incorporated as seed coatings . Also , keep in mind that the root nodules that form on hydroponic legume crops are visible and appear as knobbly , rounded growths that can reach the size of a pea , firmly attached to the root system . These have sometimes been mistaken for root pathogens or other diseases by inexperienced growers , but they are a perfectly natural occurrence .
To speed up the process , plants can be inoculated with the correct species of nitrogen-fixing bacteria .”
GOURMET LEGUMES
The legume crops commonly grown in hydroponic systems tend to exclude commodity crops such as pulses and instead focus on the higher-value fresh vegetable , garnish , and gourmet baby produce types . The development of new , dwarf , or “ container ” varieties of peas and beans are particularly advantageous to indoor gardens and small hydroponic systems , as they produce high yields on relatively small and compact plants that don ’ t require trellises or supports like the tall climbing types do . Both peas and beans are also used as micro greens and sprouts , taking even less space than mature plants and requiring only a few days from seeding to harvest . Peanut plant seedlings . grow cycle 35