Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?


--
__Pascal Bourguignon__ http://www.informatimago.com/

Our enemies are innovative and resourceful, and so are we. They never
stop thinking about new ways to harm our country and our people, and
neither do we.

Its probably an experiment that has been done in many high schools around
the world.

How about growing a fungus on Uranus instead?

BTW, what is your idea of a "normal" plant?


"Pascal Bourguignon" wrote in message
...

Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?


--
__Pascal Bourguignon__ http://www.informatimago.com/

Our enemies are innovative and resourceful, and so are we. They never
stop thinking about new ways to harm our country and our people, and
neither do we.

Why doesn't someone moderate this post??



"Cereus-validus" wrote in message
om...
Its probably an experiment that has been done in many high schools around
the world.

How about growing a fungus on Uranus instead?

BTW, what is your idea of a "normal" plant?


"Pascal Bourguignon" wrote in message
...

Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?


--
__Pascal Bourguignon__ http://www.informatimago.com/

Our enemies are innovative and resourceful, and so are we. They never
stop thinking about new ways to harm our country and our people, and
neither do we.

"Cereus-validus" writes:
"Pascal Bourguignon" wrote in message
...

Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?

Its probably an experiment that has been done in many high schools around
the world.

So, what are the results?

How about growing a fungus on Uranus instead?

BTW, what is your idea of a "normal" plant?

Any plant you could find in your garden, like tomatoes, beans, etc.

--
__Pascal Bourguignon__ http://www.informatimago.com/

Our enemies are innovative and resourceful, and so are we. They never
stop thinking about new ways to harm our country and our people, and
neither do we.

Pascal Bourguignon schreef
Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?

* * *
This will depend on exact circumstances, but put like that plants will grow
as much in a day no matter how long it lasts (24 hours or a month)

On the moon, it is either always sunny or always in the dark, not 14
hours on and 14 hours off.


On 02 Sep 2004 08:58:54 +0200, Pascal Bourguignon
wrote:

"Cereus-validus" writes:
"Pascal Bourguignon" wrote in message
...

Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?

Its probably an experiment that has been done in many high schools around
the world.

So, what are the results?

How about growing a fungus on Uranus instead?

BTW, what is your idea of a "normal" plant?

Any plant you could find in your garden, like tomatoes, beans, etc.

In article ,
P van Rijckevorsel wrote:
Pascal Bourguignon schreef
Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?

* * *
This will depend on exact circumstances, but put like that plants will grow
as much in a day no matter how long it lasts (24 hours or a month)

Surely they'll grow more in 14 days of constant light than in 12-24
hours of same, but the 14 days of darkness will be very harmful for
most plants at growing temperatures. Prolonged darkness causes
etiolation and yellowing in all growing plants. If I leave
something on the lawn, the grass underneath takes only a few days to
look unhealthy, and two weeks would kill most of it, except, of course,
in winter when the plants are dormant. You can kill most weeds, or set
them way back, by use of light blocking mulches.

Constant light can be helpful when plants are in a vegetative state,
but if you do or don't want flowering, you have to control night
length. For example, short nights (long days) will make lettuce and
most brassicas (cabbage family vegetables) go to seed instead of
producing leaves, which is undesirable. Many ornamentals (and
fall-flowering weeds) need long nights (short days) to stimulate
flowering. I don't know which vegetables are in this group because
most of my experience is with a cold temperate climate. I do know that
beans (Phaseolus) had their short-day-flowering requirement bred out of
them as agriculture moved north from Mexico to southern Canada in
pre-Columbian times. Day length requirements could probably be bred
out of a crop, possibly very quickly by genetic engineering techniques
once the relevant genes are idenitified, but you aren't going to have
as easy a time getting around the fact that most plants will use up
their reserves and begin to die well before they've survived 14 days of
darkness.

Considering the difficulties of building a transparent structure that
is strong enough to resist vacuum and meteorites on the moon, I think
it would be much more practical to have surface solar collectors to
generate electricity to power lights to grow plants. Obviously, you'd
need some method of energy storage for the lunar nights, but growing
crops under artificial lighting is a solved problem. For example,
vegetables have been grown in deep mines in northern Ontario, taking
advantage of the natural heat at depth and the cost of supplying
vegetables in reasonable condition to remote areas with too short a
season and too little heat to grow them on the surface profitably.
IIRC, these projects mostly produce tomatoes and cucumbers, but there's
a lot of developed technology for growing lettuce in surface
greenhouses with supplemental lighting in winter at higher latitudes in
Europe where less supplemental heating is needed in such structures
than in Canada.

Note that your lunar garden provides the valuable function of removing
CO2 from the air as well. Many plants grow better in elevated levels
of CO2, and it's sometimes used commercially to increase growth in
greenhouse lettuce crops, usually by burning propane.

Btw, you might consider how else this lunar colony is getting its
energy. Is it all solar, or is some derived from e.g. a nuclear
reactor? In the latter case, there may well be plenty of energy
available to power lighting for plants.

On Thu, 02 Sep 2004 09:04:51 GMT, Elie Gendloff
wrote:

On the moon, it is either always sunny or always in the dark, not 14
hours on and 14 hours off.



\Maybe that's why he said 14 days, not 14 hours. suppose?



On 02 Sep 2004 08:58:54 +0200, Pascal Bourguignon
wrote:

"Cereus-validus" writes:
"Pascal Bourguignon" wrote in message
...

Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?

Its probably an experiment that has been done in many high schools around
the world.

So, what are the results?

How about growing a fungus on Uranus instead?

BTW, what is your idea of a "normal" plant?

Any plant you could find in your garden, like tomatoes, beans, etc.

--

- Charles
-
-does not play well with others

Elie Gendloff wrote in message . ..
On the moon, it is either always sunny or always in the dark, not 14
hours on and 14 hours off.

No, check any adequate reference work for "lunar day". Unless you're
situated on the terminator, it's approximately 14 days 18 hours light,
14 days 18 hours dark.

--
Chris Green

"Pascal Bourguignon" wrote in message
...

Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?

The ultraviolet light in the sun light on the moon would kill most plants.

Some will adapt to the 14 day of sun an night but most higher plants would
not do well. Lichens would do fine. They might even stand the UV.
--
Gordon

Gordon Couger
Stillwater, OK
www.couger.com/gcouger

schreef
Considering the difficulties of building a transparent structure that
is strong enough to resist vacuum and meteorites on the moon, I think
it would be much more practical to have surface solar collectors to
generate electricity to power lights to grow plants. Obviously, you'd
need some method of energy storage for the lunar nights, but growing
crops under artificial lighting is a solved problem. For example,
vegetables have been grown in deep mines in northern Ontario, taking
advantage of the natural heat at depth and the cost of supplying
vegetables in reasonable condition to remote areas with too short a
season and too little heat to grow them on the surface profitably.
IIRC, these projects mostly produce tomatoes and cucumbers, but there's
a lot of developed technology for growing lettuce in surface
greenhouses with supplemental lighting in winter at higher latitudes in
Europe where less supplemental heating is needed in such structures
than in Canada.

Note that your lunar garden provides the valuable function of removing
CO2 from the air as well. Many plants grow better in elevated levels
of CO2, and it's sometimes used commercially to increase growth in
greenhouse lettuce crops, usually by burning propane.

Btw, you might consider how else this lunar colony is getting its
energy. Is it all solar, or is some derived from e.g. a nuclear
reactor? In the latter case, there may well be plenty of energy
available to power lighting for plants.

* * *
Yes, I did not think this through. All things being equal the total amount
of assimilates will be the same for every day = light+dark-period
(photosynthesis going on until the cut-off point is reached by water
shortage), but respiration (per light+dark-period) will increase 28-fold and
the plant will die.

Of course it is entirely academic, as any kind of structure built on the
moon that would keep out a vaccuum would also alter just about all the
circumstances. A meaningful answer is not really possible. Almost certainly
some kind of artificial lighting scheme would be put in effect (perhaps
something involving mirrors and satelites?), almost as a matter of course.
PvR

A Science Fiction book from the fifties will likely go into the matter more
deeply. I remember one of them speculating on the effect of 'virgin' moon
soil on plant growth.

"Gordon Couger" writes:

"Pascal Bourguignon" wrote in message
...

Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?

The ultraviolet light in the sun light on the moon would kill most plants.

I assume that UV filters would be integrated to the green-house...


Some will adapt to the 14 day of sun an night but most higher plants would
not do well. Lichens would do fine. They might even stand the UV.

What about genetic modifications to help tomatoes and potatoes adapt
to that schedule?


--
__Pascal Bourguignon__ http://www.informatimago.com/

Our enemies are innovative and resourceful, and so are we. They never
stop thinking about new ways to harm our country and our people, and
neither do we.

writes:

In article ,
P van Rijckevorsel wrote:
Pascal Bourguignon schreef
Has the experiment of growing plants under the light conditions of the
Moon surface ever been done? What would happen if you tried to grow
normal plants with lights on for 14 days and off for 14 days?

* * *
This will depend on exact circumstances, but put like that plants will grow
as much in a day no matter how long it lasts (24 hours or a month)

Surely they'll grow more in 14 days of constant light than in 12-24
hours of same, but the 14 days of darkness will be very harmful for
most plants at growing temperatures. Prolonged darkness causes
etiolation and yellowing in all growing plants. If I leave
something on the lawn, the grass underneath takes only a few days to
look unhealthy, and two weeks would kill most of it, except, of course,
in winter when the plants are dormant. You can kill most weeds, or set
them way back, by use of light blocking mulches.

Constant light can be helpful when plants are in a vegetative state,
but if you do or don't want flowering, you have to control night
length. For example, short nights (long days) will make lettuce and
most brassicas (cabbage family vegetables) go to seed instead of
producing leaves, which is undesirable. Many ornamentals (and
fall-flowering weeds) need long nights (short days) to stimulate
flowering. I don't know which vegetables are in this group because
most of my experience is with a cold temperate climate. I do know that
beans (Phaseolus) had their short-day-flowering requirement bred out of
them as agriculture moved north from Mexico to southern Canada in
pre-Columbian times. Day length requirements could probably be bred
out of a crop, possibly very quickly by genetic engineering techniques
once the relevant genes are idenitified, but you aren't going to have
as easy a time getting around the fact that most plants will use up
their reserves and begin to die well before they've survived 14 days of
darkness.

Considering the difficulties of building a transparent structure that
is strong enough to resist vacuum and meteorites on the moon, I think
it would be much more practical to have surface solar collectors to
generate electricity to power lights to grow plants. Obviously, you'd
need some method of energy storage for the lunar nights, but growing
crops under artificial lighting is a solved problem. For example,
vegetables have been grown in deep mines in northern Ontario, taking
advantage of the natural heat at depth and the cost of supplying
vegetables in reasonable condition to remote areas with too short a
season and too little heat to grow them on the surface profitably.
IIRC, these projects mostly produce tomatoes and cucumbers, but there's
a lot of developed technology for growing lettuce in surface
greenhouses with supplemental lighting in winter at higher latitudes in
Europe where less supplemental heating is needed in such structures
than in Canada.

Note that your lunar garden provides the valuable function of removing
CO2 from the air as well. Many plants grow better in elevated levels
of CO2, and it's sometimes used commercially to increase growth in
greenhouse lettuce crops, usually by burning propane.

Btw, you might consider how else this lunar colony is getting its
energy. Is it all solar, or is some derived from e.g. a nuclear
reactor? In the latter case, there may well be plenty of energy
available to power lighting for plants.

Thank you for your comprehensive answer.

Indeed, if there's nuclear energy available, it would be simplier to
use artificial light. But storing solar energy is hard and not too
efficient (you need a lot of heavy batteries, or complex
electro-chemical processing), so if natural light can be used at least
half of the time, the better.

--
__Pascal Bourguignon__ http://www.informatimago.com/

Our enemies are innovative and resourceful, and so are we. They never
stop thinking about new ways to harm our country and our people, and
neither do we.

In article ,
P van Rijckevorsel wrote:
Yes, I did not think this through. All things being equal the total amount
of assimilates will be the same for every day = light+dark-period
(photosynthesis going on until the cut-off point is reached by water
shortage), but respiration (per light+dark-period) will increase 28-fold and
the plant will die.

Hmm. Assuming somebody is providing water and other reasonable care to
these plants, they will respire for 29+ days of the month, and
photosynthesize around the clock for the other 14.5+. They probably
won't grow twice as fast during the round-the-clock light phase than
they would with 12 hours on and 12 hours off, but they will grow at
least somewhat more. Whether they can accumulate enough photosynthate
to survive the dark half of the cycle is problematic, but they will
certainly get etiolated and weakened, and do a poor job of removing CO2
to purify the air for the humans in the habitat, much less provide them
with vegetables. If the plants are being used to purify waste water,
your habitat will end up in deep... umm... unprocessed waste water for
half the month.

I think we may be saying the same thing, but it's hard to tell, since
the word "day" is being used for three very different amounts of time
here. From real life experience, I know that I get lots more than a
day's growth out of 14 terrestrial days of constant light than from one
day, but probably not twice as much as 14 days of 12-hours-on 12-hours-off
lighting under the same conditions, i.e. raising garden transplants
under fluorescent lights in my basement. I check the plants daily and
water and fertilize as needed.

Of course it is entirely academic, as any kind of structure built on the
moon that would keep out a vaccuum would also alter just about all the
circumstances. A meaningful answer is not really possible. Almost certainly
some kind of artificial lighting scheme would be put in effect (perhaps
something involving mirrors and satelites?), almost as a matter of course.

Note that you aren't going to get much light for a good bit of the lunar
day when the sun is near the horizon. Overall, lighting is likely to be
one of the least expensive inputs to this scheme, considering that all
or most of the materials are going to have to be imported from Earth,
and a catastrophic failure could result in lethal CO2 poisoning for
everybody in the habitat. (10% CO2 is lethal to most mammals.)

A Science Fiction book from the fifties will likely go into the matter more
deeply. I remember one of them speculating on the effect of 'virgin' moon
soil on plant growth.

Most science fiction uses handwaving instead of even
back-of-the-envelope calculations for these things. The writer refers
to hydroponics for air quality, fresh veggies and even ignores the
waste water aspects (who wants to eat food grown on sewage in our
culture?), plus a nice park or such for the characters to interact in.
These guys are writing stories, not engineering manuals, and the "hardy
unsung engineers create a paradise fit for women and children by
cleverly building gadgets" story is kind of passe', and was seldom very
practical in the first place. But it sold magazines to teenage boys.

IIRC, since lunar and Martian regosols have never been exposed to
weathering and leaching, they are full of salts to a toxic level for
plants What's more, they've never been exposed to oxygen, so are
generally intensely reducing and will gobble up all that expensive
oxygen you need to breathe and be pretty caustic to handle or try to
grow in.

For a well-written novel that considers the problems of jump-starting
an economy and ecology on Mars, read Kim Stanley Robinson's Red Mars.
It describes the chemical properties of Martian regosols, and how the
characters deal with them.

Interestingly, the main reason the Biosphere II habitat failed was that
the designers didn't take into account that concrete absorbs CO2 from
the air for years after it first sets, converting calcium oxide to
calcium carbonate. The concrete structure constantly drained CO2 from
the closed system, depriving the plants so that food production was
much less than expected. There's a lot to be learned about the details
of maintaining closed systems for any but rather short time periods,
and especially when resupply is extremely difficult and expensive.

It's a lot of fun to speculate about, however.

schreef
Hmm. Assuming somebody is providing water and other reasonable care to
these plants, they will respire for 29+ days of the month, and
photosynthesize around the clock for the other 14.5+.

* * *
Yes, it is all in the assumptions. And OP provided very little in the way of
common ground to base assumptions on.

* * *
They probably
won't grow twice as fast during the round-the-clock light phase than
they would with 12 hours on and 12 hours off, but they will grow at
least somewhat more. Whether they can accumulate enough photosynthate
to survive the dark half of the cycle is problematic, but they will
certainly get etiolated and weakened, and do a poor job of removing CO2
to purify the air for the humans in the habitat, much less provide them
with vegetables. If the plants are being used to purify waste water,
your habitat will end up in deep... umm... unprocessed waste water for
half the month.

I think we may be saying the same thing, but it's hard to tell, since
the word "day" is being used for three very different amounts of time
here.

* * *
A day is a light and darkperiod (i.c. a month on the moon). However, as soon
as people actually go and live on the moon an artificial day will be
established (probably of 24 hours).
* * *

It's a lot of fun to speculate about, however.

* * *
Possibilities are endless, which makes sure that SF stories that
conscientiously try and get it right become unreadable quickly.
PvR