NASA
has

funded

research


and

development


of


new


advanced


materials

to


improve

Aeroponic


reliability


and
maintenance

reduction.


It

also


has

determined


that


high


pressure


hydro

-

atomized

mist


of


5-

50

micro

-

meters
micro
-

droplets

is


necessary

for


long

-

term

Aeroponic


growing.


For

long

-

term

growing,


the


mist


system

must
have
significant


pressure


to


force


the


mist


into

the


dense


root


systems.



Repeatability


is


the


key

to


Aeroponics
and
includes

the


hydro

-

atomized

droplet

size.

Degradation


of


the


spray


due

to


mineralization

of


mist


heads
inhibits
the


delivery


of


the


water


nutrient


solution,


leading


to


an

environmental


imbalance

in


the


air

culture
environment.

Special


low

-

mass


polymer

materials

were

developed

and

are


used

to


eliminate


mineralization

in
next

generation


hydro

-

atomizing


misting

and

spray


jets.
Nutrient

uptake
The

discrete


nature


of


interval


and

duration

Aeroponics


allows


the


measurement


of


nutrient


uptake


over


time
under
varying


conditions.


An


Aeroponic


system

was


used

for


non-

destructive


measurement


of


water


and

ion
uptake

rates


for


cranberries.


In


the


study,


these


researchers


found


that


by

measuring

the


concentrations


and
volumes

of


input


and

efflux


solutions,


they


could


accurately

calculate


the


nutrient


uptake


rate.


After

verification
of

their


analytical


method,


they


went


on

to


generate


additional


data


specific


to


the


cranberry,


such
as
diurnal


variation


in


nutrient


uptake,


correlation

between


ammonium


uptake


and

proton


efflux,


and

the
relationship
between


ion


concentration


and

uptake.


Work


such

as

this

not


only


shows


the


promise

of
Aeroponics

as

a

research


tool


for


nutrient


uptake,


but


also


opens


up

possibilities

for


the


monitoring

of


plant
health

and

optimization


of


crops


grown


in


closed


environments.
Atomization

(>65


pounds


per


square

inch


(450


kPa)),


increases


bioavailability


of


nutrients,


consequently,
nutrient

strength

must


be

significantly

reduced

or


leaf


and

root


burn


will


develop.


Note

the


large


water


droplets
in

the


photo


to


the


right.


This


is


caused


by

the


feed


cycle


being


too


long


or


the


pause


cycle


too


short;


either
discourages

both


lateral


root


growth


and

root


hair


development.


Plant


growth


and

fruiting


times


are
significantly
shortened


when


feed


cycles


are


as

short


as

possible.


Ideally,


roots


should


never


be

more


than
slightly
damp


nor


overly

dry.


A

typical


feed/pause


cycle


is


<


2

seconds


on,


followed

by

~1.5

-

2

minute


pause

-
24/7,

however,

when


an

accumulator


system

is


incorporated,


cycle


times


can

be

further


reduced

to


<


~1
second

on,


~1


minute


pause.
Types

of


Aeroponics
Low-
pressure

units
In

most


low

-

pressure


Aeroponic


gardens,


the


plant


roots


are


suspended


above


a

reservoir


of


nutrient


solution
or

inside

a

channel


connected

to


a

reservoir.


A

low

-

pressure


pump


delivers


nutrient


solution


via


jets

or


by
ultrasonic

transducers,


which

then


drips

or


drains


back

into

the


reservoir.


As

plants

grow

to


maturity

in


these
units
they


tend


to


suffer


from

dry


sections

of


the


root


systems,


which

prevent


adequate

nutrient


uptake.


These
units,

because


of


cost,


lack


features

to


purify


the


nutrient


solution,


and

adequately


remove


in

-
continuities,

debris,


and

unwanted


pathogens.


Such


units

are


usually

suitable


for


bench


top


growing


and
demonstrating

the


principles


of


Aeroponics.
High-
pressure

devices
High-
pressure


Aeroponic


techniques,

where


the


mist


is


generated


by

high

-

pressure


pumps,


are


typically

used