Quixote Posted August 22, 2015 I successfully sprouted three little loph seedlings, and they look healthy enough, but stopped growing. They basically haven't grown since they sprouted, each of them has those little hairs/baby spines, they are dark green colour, but they just won't grow! In the beginning, I kept them under plastic wrap, but I took that off because I feared mold (it killed a previous batch). Then I had them in the sun for some time, they turned reddish so I put them in the shade again. Now they are no longer red, and I have tried having them in half shade. In the last couple of weeks I put them in quite a lot of sun, thinking they might miss sun and warmth. They don't seem to be hurt, but won't grow either. What can I do? I fertilized them only once. Share this post Link to post Share on other sites
zelly Posted August 23, 2015 i recently grew out a tub full of these guys....seeds were planted on 4-10-15 and they remained in the sealed plastic tub for 2 months under florescent lights. Month 3 I cracked opened the lid to harden them off, but still under the lights. Last week I put the tub in my gh where the seedlings & plants are in full sun but uv protected. Currently they're .5 cm in size and growing quite nicely back atcha, at what age would you put a newborn infant out in the full sun? Share this post Link to post Share on other sites
Anodyne Posted August 23, 2015 Don't they always do this? I thought they grow fast initially as the plant uses the reserves that were stored in the seed, then the growth stalls for awhile until the seedlings get a foothold & send out roots to find their own food. 1 Share this post Link to post Share on other sites
Quixote Posted August 23, 2015 (edited) Don't they always do this? I thought they grow fast initially as the plant uses the reserves that were stored in the seed, then the growth stalls for awhile until the seedlings get a foothold & send out roots to find their own food. I don't know. It's my first attempt at growing these from seeds. I don't have any heating mat or flourescent lights, just a little pot in a window sill... I hope you are right. They don't seem to be unhappy, just not in the mood for growing. Might be because they need the warmth, but without the direct sun. And the only way I have of making it hot for them is to place them in the sun... Edited August 23, 2015 by Quixote Share this post Link to post Share on other sites
Philocacti Posted August 24, 2015 You can put a piece of cloth or a few layers of tissue paper on it and place it in the sun to warm up and not getting burnt at the same time. However you have to put enough tissues to diffuse all the extra light. 2 Share this post Link to post Share on other sites
Quixote Posted August 24, 2015 Good idea about the tissue paper. But since they are not turning red, I guess they are not getting burned? Share this post Link to post Share on other sites
Quixote Posted September 13, 2015 (edited) Update: I put the seedlings under some plastic cover again, with ventilation holes. But one of them died because of mold, so I removed the lid again. Now there are two left. They look healthy, green, 5mm diameter. On rainy days I take them away from the window and place them under a a halogen spot in my kitchen (propped up by a bottle of Glenfiddich 15). The idea is that they need more heat than my North European window-sill is able to provide, but that on the other hand, the summer sunlight up here is too bright. So, under the halogen they should get a bit less intense light, but a whole lot more heat. Edited September 13, 2015 by Quixote Share this post Link to post Share on other sites
Spanishfly Posted October 14, 2015 (edited) Quixote - incandescent lights, including halogen - are totally the wrong spectrum for raising virtually any type of seedlings. My standard light for cactus seed raising is a pair of 20W 6000K fluoros - from a Chinese bazaar for a few Euros each. In the winter I put my seed trays on a reptile heat mat (from a pet store) plugged into a lamp dimmer to control the temperature. Edited October 14, 2015 by Spanishfly Share this post Link to post Share on other sites
Quixote Posted October 19, 2015 Quixote - incandescent lights, including halogen - are totally the wrong spectrum for raising virtually any type of seedlings. My standard light for cactus seed raising is a pair of 20W 6000K fluoros - from a Chinese bazaar for a few Euros each. In the winter I put my seed trays on a reptile heat mat (from a pet store) plugged into a lamp dimmer to control the temperature. Not sure what you mean about the spectrum, as halogen is supposed to match 99 pct of the sun's spectrum? At least that's what I read... Share this post Link to post Share on other sites
Spanishfly Posted October 19, 2015 No incandescent bulb can have a colour temperature close to the sun´s 5800K. I use 6000K fluoros. Share this post Link to post Share on other sites
zelly Posted October 20, 2015 No incandescent bulb can have a colour temperature close to the sun´s 5800K. I use 6000K fluoros. Like all incandescent light bulbs, a halogen lamp produces a continuous spectrum of light, from near ultraviolet to deep into the infrared.[13] Since the lamp filament can operate at a higher temperature than a non-halogen lamp, the spectrum is shifted toward blue, producing light with a higher effective color temperature. https://en.wikipedia.org/wiki/Halogen_lamp Share this post Link to post Share on other sites
Spanishfly Posted October 20, 2015 (edited) Sure, halogen lamps operate at a higher temperature than standard incandescent bulbs. But no incandescent lamp can produce a colour temperature higher than 3700K - the melting point of its tungsten filament !!!!! For your cacti sprouts invest in some 6000K fluoros. Edited October 20, 2015 by Spanishfly Share this post Link to post Share on other sites
Quixote Posted October 24, 2015 (edited) No incandescent bulb can have a colour temperature close to the sun´s 5800K. I use 6000K fluoros. I think I mixed up colour temperature with CRI - Colour Rendering Index. So, basically, my cactus will look its natural colours when under a halogen lamp, but that doesn't necesarily mean the cactus is happy. I wonder if halogens are completely useless for seedlings, or if they are just not optimal? Edited October 24, 2015 by Quixote Share this post Link to post Share on other sites
BedOSpines Posted October 25, 2015 halogens are good for cooking your seedlings ;p. 1 Share this post Link to post Share on other sites
zelly Posted October 25, 2015 But no incandescent lamp can produce a colour temperature higher than 3700K Maybe not in your part of the world? Color: 6500K Full-Spectrum Frosted https://www.iqlightbulbs.com/satco_s4816_a19f60vlx.asp Color: 6500K Full-Spectrum Clear https://www.iqlightbulbs.com/satco_s4819_a21c75vlx.asp Share this post Link to post Share on other sites
Spanishfly Posted October 25, 2015 (edited) You said it, bedofspines / about all they are good for !!!!! Edited October 25, 2015 by Spanishfly Share this post Link to post Share on other sites
2XB Posted October 25, 2015 So Zelly are you saying we can grow plants under halogen/incandescent or are you just saying they have a Broad colour sprectrum.. . Because everything I've read about growing with incandescent says yes you can use them but the results are shitty.. Would love to learn otherwise man as naturally the bulbs you are linking are much cheaper than. HPs, CFl or whatever are the popular grow light options at the moment.. . I have read they are great for. Red spectrum but all those graphs don't mean. Much to me.. .... Please elaborate? Share this post Link to post Share on other sites
Spanishfly Posted October 25, 2015 (edited) I wrote this twice - sorry all Edited October 25, 2015 by Spanishfly Share this post Link to post Share on other sites
Spanishfly Posted October 25, 2015 OH FGS - how many times does it have to be said ??!!! You cannot grow cacti seedlings under incandescent lights - which includes halogen. Get some fluoros - if you are so impoverished that you can´t even stretch to a couple of fluoros then just give it up. Jeez what do we have here - schoolkids with NO income at all??!!! Share this post Link to post Share on other sites
BedOSpines Posted October 25, 2015 (edited) You can, but only if your Richie Rich, and have lots of fans. The luminous efficacy of a typical incandescent bulb is 16 lumens per watt, compared with 60 lm/W for a compact fluorescent bulb or 150 lm/W for some whiteLED lamps.[3] - edited grammar. Edited October 25, 2015 by Bedofspines Share this post Link to post Share on other sites
Spanishfly Posted October 25, 2015 (edited) If you´re RICH (get the basic grammar right)??? My two fluoros cost me €8 - if you can´t afford that pittance you should give up !! Edited October 25, 2015 by Spanishfly 1 Share this post Link to post Share on other sites
BedOSpines Posted October 25, 2015 (edited) Sure, halogen lamps operate at a higher temperature than standard incandescent bulbs. But no incandescent lamp can produce a colour temperature higher than 3700K - the melting point of its tungsten filament !!!!! For your cacti sprouts invest in some 6000K fluoros. By the way, the k in 3700k refers to Kelvin. Not degrees. https://en.m.wikipedia.org/wiki/Color_temperature 1600 melting point of the glass. Edited October 25, 2015 by Bedofspines Share this post Link to post Share on other sites
BedOSpines Posted October 25, 2015 I've had my loph seedlings under two of these, they are doing well. http://www.ebay.com.au/itm/4pcs-50cm-7020-12V-LED-Strip-Light-Cool-White-Bars-Camping-Caravan-Boat-Car-NEW-/351542014745?hash=item51d9897319:g:rf8AAOSwo0JWJyWM Share this post Link to post Share on other sites
Spanishfly Posted October 25, 2015 (edited) Yes I know Edited October 25, 2015 by Spanishfly Share this post Link to post Share on other sites
Spanishfly Posted October 25, 2015 (edited) Yes, Bedofspines - I sort of know what a Kelvin is - I used to teach physics - first at school then in the Royal Navy. Initially a degree Absolute, then a degree Kelvin - then just a Kelvin (K). The temperature interval is the same as a degree Celsius ( C ). Edited October 25, 2015 by Spanishfly Share this post Link to post Share on other sites
