Cactus under lights!?

[lhb2444]

Hey hey,

I have a 250watt fluro light that I use to grow leafy greens like lettuces and things and I'm wondering whether it would be useful for drying out cuttings/rooting cuttings, I can obviously easily control the amount of water the cactus is getting when under cover to ensure they don't rot so does anyone had any experiences with this?

And also following on from this would I be able to keep the cactus from going in dormancy over the winter months by imitating its summer growing conditions?

Thanks in advance!

[Foo]

[BBGONE]

Hey hey,

I have a 250watt fluro light that I use to grow leafy greens like lettuces and things and I'm wondering whether it would be useful for drying out cuttings/rooting cuttings, I can obviously easily control the amount of water the cactus is getting when under cover to ensure they don't rot so does anyone had any experiences with this?

And also following on from this would I be able to keep the cactus from going in dormancy over the winter months by imitating its summer growing conditions?

Thanks in advance!

 

Yes it must work.

The only I advise is to use Metal Hallide lamps instead of flouro.

Starting from 250 W, Metal Hallides are more efficient.

Personaly I have 400 W lamp (with reflector) with color temp. 6000 K.

The light spreads better, and its intensity close to sunlight.

Flouro light generaly good for short plants,

and it is better to have U tube CFL lamps (like OSRAM dulux L),

and not spiral lamps.

One more point, if you growing cacties, it is better to use lamps that have some blue waves.

the Color of the cacties would be better, and they are more stout, if they were grown

under lamps which contain blue spectrum.

So better to take lamps with higher color temp (6000 K and more).

HPS contains very little blue spectrum, the cacti will grow, but be thin.

Edited April 7, 2011 by BBGONE

[bℓσωηG]

4 sale 250watt metal halide lamp, ballast, shade used one year only make an offer

[2Deep2Handle]

lhb i have to agree with everything BBGONE stated! MH or HPS would prob be better,

as for me...i use the u shaped compact flouros (54watt 5200k bulbs (there like $16 from bunnings and just wire your own sockets))

5200k (or close) vegatating

2500k (or close-id slip a little higher not lower) to TRY and reproduce flower or fruit.

You really need HPS or MH (MH actually emits the best spectrum for budding but HPS gives better overall growth(in most species))

Cheap DIY CFL grow light

I veg all my small cacti pups and cuts to about 5 inches. Opuntia in particular seem to love it.

300watt flouro bench with fan on it to mimic wind for some things and reduce heat running 20/4. Cacti love the heat, but too much humidity for too long increases the risk of rot among many species of cacti, so if the heat gets above 30c-ish, then you don't want a stupidly high humidity as well. Just asking for rot IMO

If you go with flouros effective distance is like no greater than 5 inches but like 1-3 inch is most prefereable.

Edited April 7, 2011 by 2Deep2Handle

[Rabelais]

Remember Cacti use CAM Photosynthesis. Someone more knowledgeable should confirm but I believe it means they wont grow under 24hr light cycle, remember they will probably need at least 6 hrs of darkness (they only take in CO2 during night?). I know it probably sounds obvious, but I have heard of many people who use 24hr cycles for certain plants to keep things toasty in winter.

Something that might trip-up someone starting out in growing cactus under lights.

[tripsis]

Good point Dale. That's right, they fix CO₂ at night, so I expect that darkness would be necessary for them.

[Foo]

Good tips all round!!

[C_T]

i don't see trich doing very good under lights... the cost/benefit ratio would be quite negative.

[Gunter]

i used HPS lighting to raise cactus seedlings for many years, it works very well, but it is not ideal for larger plants whose main photosynthetic surfaces are on their sides, not their tops, so a light positioned for cactus of a columnar nature should not be on top, it should be at the side or an angle

[Evil Genius]

Hi lhb, using HPS Lamps to bring Cacti over the winter is possible but very uneconomical. Its very expensive and it wastes a lot of energy by producing heat. If i were you, i´d get me a nice 150-300 Watt LED Lamp. Its totally sufficient and compared to the costs of a HPS lamp, its way less expensive. In my eyes, LED Lamps are the future because they become more efficient every year. bye Eg

[BBGONE]

i don't see trich doing very good under lights... the cost/benefit ratio would be quite negative.

 

I grow Trich. seedling under CFL light upto 2 years old.

The results much better than growing them under sunlight on windosill.

This is because the light is stable (no bad weather, no clouds, no too hot direct sunlight)

And they dont need stagnation period, growing two years without breaks with day time between 14-16 hours.

So if you grow from seeds, in two years the cacties are much larger and healthy than ordinary growing.

And there is one more benefit, the light goes verticaly on them (on their tops!) - but just a little slanted, so they grow directly upright,

and getting much fatter (to absorb more lights).

If you need to provide more lights from sides, add side reflector (as in growboxes all sides reflect the light)

I use 2 U- shaped lamps OSRAM DULUXE L 55 W (totally 110 W) with ALANOD reflector.

I'm planning this winter (i'm situated in nothern hemisphere- europe) to use MH lamp (400 W) on larger plants.

My lamp produces 150 000 LUX on 50 cm distance from it.

It can be used to grow 90 cm. cacties all year round (I saw pictures on our local forum).

The first attachment is T. Pachanoi (4 years old, grown fromm seeds, 90 cm long) in hydro culture under HPS lights, due to lack blue spectrum is too thin. (this is not mine, i downloaded this picture from another forum)

The second attachment is our locally manufactured HID lamp with built-in internal reflector.

It has large bulb and is only slightly heated on the surface (no more 100 C).

Edited April 13, 2011 by BBGONE

[BBGONE]

Hi lhb, using HPS Lamps to bring Cacti over the winter is possible but very uneconomical. Its very expensive and it wastes a lot of energy by producing heat. If i were you, i´d get me a nice 150-300 Watt LED Lamp. Its totally sufficient and compared to the costs of a HPS lamp, its way less expensive. In my eyes, LED Lamps are the future because they become more efficient every year. bye Eg

 

In my opinion LED lamps is marketing gimmick.

If you look more closely on their specs. they provide less lumen output per watt (55 Lm/W) in comparison to HIDs (MH 90 Lm/W, HPS 100 Lm/W).

And transformer gives no less heat than from HIDs, only distributed over more space.

LED lights cost incomparably higher than HIDs.

So no economy.

Edited April 7, 2011 by BBGONE

[Gunter]

one day perhaps the LEDs will be as cost effective as the HPS, but so far they produce less light per unit of electricity and their narrow spectrum seems to be a drawback, i've yet to see LEDs produce decent growth compared to HPS in side by side comparisons with any plant species

I've found that a 400W HPS really does not cost much to run and it is excellent for cactus seedlings

at about $0.05-0.10 per hour (US dollars) 12 hours a day nearly a dollar at most and often less than that, this means a total cost per month of about 20-30$, something many people can justify easily

for seedlings one can grow 10,000 seedlings easily in a small space, at the cost of $20-30 a month that is easily worth it, however for larger plants who do not respond well to overhead lighting it is far harder to justify.

[tripsis]

I've read that HPS is better for inducing flowering and MH better for vegetative growth. Is that correct?

[mac]

I've read that HPS is better for inducing flowering and MH better for vegetative growth. Is that correct?

I have heard this, i think it would also depend on the spectrum & colour of the lamp used

[Gunter]

in my experience HPS promotes a bit more elongation, not actually thinner growth per say, just more elongated growth

but is not any more suited for flowering than MH

both MH and HPS come in a variety of flavor/colors these days and one can select a form that is designed for horticultural use

however side by side studies of the most basic forms of the two lights are fairly easy to find and do not show one lamp to be superior to the other in any significant way with the exception of HPs tending to be a bit more efficient in terms of light produced per unit of energy

[tripsis]

What colour temperature is best for vegetative growth (of any plant, not just cacti)?

Edit: Also, is there an approximate conversion of the output of the light (in lumens) to the amount of surface area it can cover effectively?

Edited April 8, 2011 by tripsis

[mac]

wiki can explain things better than me

Blue spectrum light may trigger a greater vegetative response in plants.[2]

Red spectrum light may trigger a greater flowering response in plants.[3] If high pressure sodium lights are used for the vegetative phase, plants grow slightly more quickly, but will have longer internodes, and may be longer overall.

http://en.wikipedia.org/wiki/Grow_light

[Gunter]

those wiki references (2 and 3) have no scientific study or link and just refer to a marijuana growing page

and the word may in each of these sentences means that they are not totally accurate or demonstrated

Blue spectrum light may trigger a greater vegetative response in plants.[2]

Red spectrum light may trigger a greater flowering response in plants.

in side by side studies of grow lights I've yet to see anything like a "greater vegetative response"

the only thing clear is that red light triggers greater elongation in some species, but this does not mean that plants have less vegetative growth.

http://en.wikipedia.org/wiki/Photosynthetically_active_radiation

several studies have shown that when tested side by side, HPS lights outperform MH lights of the same wattage and the former give greater yields, largely because they tend to be more efficient and produce more lumens per watt.

http://en.wikipedia.org/wiki/File:Par_action_spectrum.gif

red is between 600-700nm, there is a rather large peak there and that corresponds to photosynthesis, the difference between red and blue light in terms of PAR is negligible in many species

[tripsis]

So, if one was to use HPS lights to overwinter plants and keep them growing, how much surface area does one 400w light cover?

[BBGONE]

So, if one was to use HPS lights to overwinter plants and keep them growing, how much surface area does one 400w light cover?

 

This depends on reflector used (and side reflectors), but no more than 4 sq. meters.

just buy cheap luxmeter and test light intensity in the area.

it must be no less than 10000 lux at the bottom of this area.

P.S. - HPS are only 10% outperform MH lamps,

but MH lamps have better spectrum, especialy for cacties, they are much more fatter in this case and have bluish

frosted skin, like on sunlight.

Edited April 8, 2011 by BBGONE

[tripsis]

Thanks, good to know a basic sort of guideline. Getting a luxmeter is a good idea.

Do HPS heat up light MH? Also, I've read that the intensity of the light can be too much for young plants. Is this true even if the lights are a fair distance from the plants?

[Gunter]

if you keep the plants away from the bulb, neither HPS or MH will be too intense for seedlings

a 400 watt light will be good for about a square meter

In my experience growth rates from HPS are better than with MH, I've grown cacti for 5+ years using HPS lighting and bulbs are available that have as much blue in them as any MH

[BBGONE]

if you keep the plants away from the bulb, neither HPS or MH will be too intense for seedlings

a 400 watt light will be good for about a square meter

In my experience growth rates from HPS are better than with MH, I've grown cacti for 5+ years using HPS lighting and bulbs are available that have as much blue in them as any MH

 

I changed lamps to MH (6000K), because i wanted that the look of cacties be better.

Maybe i'm wrong, i had not experimented much with HPS lights,

i just assumed that in nature, sunlight contains appreciable amount of blue spectrum.

It is better to experiment with different light source to select the best for cacties.

Now i grow them under CFL 6500 K, they appear to thicken more than from natural lights on windowsill.

It is maybe due to the fact, that lights pour on their tops, so they just adjust their growth point (they grow on the top) to take more light.

Even T. bridgesii seedlings (grown first year on windowsill), now have become clublike.

I found one article here http://www.kadasgarden.com/CLophophoramescaline.html

it says that for Lophs. in tissue culture the best for their growth was blue light, surprisingly the second was green,

and the third was red.

But alk. production was better in full dark (without growth at all).

I took pictures of my cacties on the fifth of april, and will take them again on the fifth of may to show the difference in their size in a month period.

Edited April 8, 2011 by BBGONE