root zone manipulation
However , root zone volume control in soilless systems helps increase the productivity and produce quality of some crops in certain situations . Vegetable seedlings grown with some root restriction usually result in shorter , hardier transplants that are better able to survive the stress of planting out and establishment . In fruiting crops like apples and grape vines , root restriction limits vegetative growth while improving the quality of the fruit in terms of soluble sugars and other parameters . There is also evidence that root restriction in the seedling stage of some hydroponic crops helps hold back excessive vegetative growth , leading to earlier flowering , more compact plants , and an advantageous vegetative-reproductive balance . To achieve this kind of root restriction , growers carefully select the size of the seedling rooting container or , as is more common , hold the seedlings in their propagation cubes / containers for a longer period so root restriction begins to occur before planting out . Other studies show root restriction can improve the nutritional value of hydroponically grown vegetables . Pak choi , edible chrysanthemum , endive , and lettuce cultured in a deep-flow system with restricted root zone tubes had an increased carbon-to-nitrogen ratio and percentage of dry matter , as well as higher ascorbic acid ( vitamin C ) and anthocyanin levels . These results could be due to a stress response like that found in crops grown under deficit irrigation or with a high EC , but it is most likely thanks to a combination of internal plant processes triggered by compounds produced by the restricted root system . Increasing root restriction , however , also inhibits growth . So , growers need to establish a compromise in the garden . Roots should be restricted to the point where a crop still produces sufficient foliage while seeing an improved nutritional value .
Sharing Substrates
In many hydroponic systems , plants often share a growing bed , container , or slab , allowing root systems to intermingle . Some studies show that plants sharing a root zone with a neighbor can produce more root mass in comparison to those growing alone . It is believed sharing space allows plants to enhance their competitive ability . These findings , however , may be species specific ; it appears that the roots of some plants can sense a neighbor ’ s roots and respond to them accordingly , while others cannot . Further studies may also eventually help us determine if and how plants grown side-by-side in hydroponic systems influence each other ’ s growth .
“ SOME STUDIES SHOW that plants sharing a root zone with a neighbor can produce more root mass in comparison to those growing alone .”
Top : Some plants produce more root mass when sharing the root zone with a neighbor .
Bottom : Hydroponic heirloom tomatoes can benefit significantly from the use of root stocks .
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