| Cactus under HPS |
El Chris
Member
Located in South East UK
User since 24
Aug 2002 - 19 posts
Posted on 11 Sep 2002 at 06:45.53
PM
|
I have half a dozen San Pedros which are
destined for my garden in Spain later on this year. Due to lack of
space in my greenhouse I have no room for these as they are in 6
inch pots and are crowding out my other cacti.
My question is
would they be OK under a couple of 400w HPS lights along with my
other plants?
They would be under 12/12 lighting with temps
between 25c and 28c for the next three months.
Once out in Spain
the temps will be quite a bit lower, the minimum is around
7c.
Will this harm the plants as they will be denied a large part
of their
dormant period by spending three months in the grow
room?
Any guidance would be much
appreciated.
Regards
El Chris
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| Re: Cactus under HPS |
Wylie
Member
Posted on 13 Sep 2002 at 02:48.38
PM
|
As far as I know your cacti will come to
no harm on a grow room. They will probably thrive, but I would
imagine them to prefer your greenhouse in Spain if you could make
room.
I am guessing when I say they will not miss their
dormant period but I believe if they are not near flowering size
then this wont be an issue. I get the journal of the British Cactus
and Succulent Society, and one contributer to the mag. is a grower
who has been having great success using artificial lights only for
the first several years of the lives of 'slow growing cacti'. By
these he means Ariocarpus and Lophophora for example.
If you
introduce cacti to a grow room shared with other plants then you
must make sure that the cacti do not get any drift from sprayed
nutrients or pesticides, even organic ones. Magnesium in the spray
will cause a harmless but unsightly black scarring on the skin, and
if my memory serves me well San Pedro's dont like organic fatty
acids (for pest control). I brush my cacti with isopropyl alcohol to
kill mealy bugs and similar, and it's always handt to have some
iso.
Good luck with the move
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| Re: Cactus under HPS |
El Chris
Member
Located in South East UK
User since 24
Aug 2002 - 19 posts
Posted on 14 Sep 2002 at 11:31.56
AM
|
Thanks for that Wylie.
Welcome to the
community.
There will no danger of drift as I don't spray my
other plants while they are flowering. I will ship them in
today.
They will be placed outside and grown in the ground when I
get them over to Andalucia.
Another BCSS member
eh?
Regards
El Chris
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| Re: Cactus under HPS |
Avalokita
Member
Located in Buckinghamshire
User since
04 Sep 2002 - 20 posts
Posted on 19 Sep 2002 at 02:51.14
AM
|
Your cacti should be fine under HPS
lights, but it depends on a couple of things. If they are 15 to 30cm
tall now, they should be fine under artificial lights for a couple
of months. HPS lights aren’t as intense as sunlight so they will
grow a bit thinner then they would outside. But if they aren’t very
tall yet, this isn’t much of an issue. A 400watt HPS light per
square metre is the minimum light they would need, but a 600 watt
light would be better. The other factor is humidity, because they
can get damaged if the humidity gets too high, as long as you have
good ventilation and the humidity doesn’t go much above 70% they
should be alright.
Cacti do really like growing under
artificial lights, and they are especially good for Lophophora’s
because it is so easy to adjust the light levels to the right
amount. However the fattest Trichocereus cacti I ever seen were
one’s I bought from a commercial cacti supplier, which were grown in
a green house. There were young ones 20 cm tall and 8 cm thick, and
a massive one which was 1.8 metres tall and 11 cm thick.
I’ve had some Trichocereus that I left outside over winter
in the Southern Midlands area in England, and they survived. They
were in a recessed covered area right next to the house, facing
south in an enclosed courtyard, so they were protected from frost,
rain and all the harsh weather. So your cacti should be able to
survive the winters in Spain. Trout’s Notes on Cacti says that they
don’t like frost and humid cold weather. Also it’s wet cold roots
that give them root rot. So when you plant them out, they should be
in an area that’s very well drained.
On the balance of
things, I think it would probably be better to bring them in for the
winter. I agree with Wylie’s advice about being careful to avoid
spray getting on them. Trichocereus cacti are covered with a
protective waxy coating, fatty acids and other sprays can dissolve
this, that’s why they get the scarring on the skin. Also be careful
to avoid knocking into them, because they will get bruised which
will cause a black mushy rot to appear.
Good luck.
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| Re: Cactus under HPS |
El Chris
Member
Located in South East UK
User since 24
Aug 2002 - 19 posts
Posted on 26 Sep 2002 at 07:02.24
PM
|
Thanks for the wisdom Avalokita.
It's
just a temporary home 'till they go abroad. I have two 400w on the
go so I have stuck them in the area where the the light footprints
overlap, they seem happy.
I'm looking forward to getting back
over to Spain to see how my last plantings are
progressing.
Good luck and regards
El Chris
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The current forum time is 13 Oct 2002
11:23.59 AM
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