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Hello fellow saber's!

I was just thinking it would be a good idea to have a pinned thread about germination and care for cacti seedlings until they are Semi-mature/mature.

At the moment i have a question also to start off.

I planted heaps of cacti seeds into some takeaway containers and most of them all germinated there was all sorts of cacti. but i think i may have left them to long eaither in to dark conditions beause they were quiet elongated or because they got to dry... as they all died :( i had them in pure river sand.

so how long should i keep them in the containers next time, how often should i water them and what lighting conditions do they need throughout their childhood (if you can call it that)?

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leaving them somewhere dark is never a good idea.

don't think, they don't need light at the beginning..., and then I will move them once the germed,... because you might forget, and you did forget to move them...

I heard as well a story here from one of the cacti specialist here, who said, he got old lazy to germ seed, to sprout because he did place the seed into full sunlight for a couple of day's befor sowing out.

I check on my seedlings at least every two day's, and although some people would idealy never open the container (in fear of introducing pest), I do it so to avoid any chance of drying out.

young cacti seedlings love water, heaps of water.

I give them 2 h direct morning sun, and the rest of the day, just bright, but I don't use take away containers, but flower pots with sheets of glass on top (or a dome made out of a soft drink bottle).

the take away containers create more algae problems then pots...

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I like the idea of this thread mate :),

If people are wanting to ask questions they should try to list the kind of cactus seed if known, if there is lighting going to be used tell us what kind of watts & the kind of medium use to sow the seeds in. The more you can add about these things the better an answer you will probably get.

jwerta, how long did your seedlings live for? The first thing that comes to mind is the river sand & lack of nutrients for your seedlings, I personally don't use straight river sand but have heard it is great for starting your seedlings but soon they will need potted up into a mix that has nutrients in the soil or they will need to be given fertilizer regularly. When making a mix to use for germinating seeds I think about how long I am planning on leaving the seedlings in there for & make up a mix that suits, for example if I was planning on grafting all the seedlings soon after germination I would probably use straight river sand.

Cheers

Jox

Edited by Jox
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I was ferting them for a while.

umm there where like 10 out of over a 500 that where still kinda green but they where very shrivled up

maybe like just under a year ahah

oh and i had them siting on a windowsill with indirect sunlight

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I agree with jox, and also don't like river sand as a medium.

but some people do alright with sand, but they use fertilizer more often me thinks...

I use (searls) seed raising mix, and sieve the top layer, so it's ultra fine, than sprinkle the seeds so they are embedded (after using the mister, the mister makes the seeds settle down), but not covered by soil.

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I started with lophs in straight sand in a takeaway container on the windowsill. They didn't germinate well and because it was my first attempt, I think I got the water/light mix wrong. They germinated in about 3 weeks, but after a month or so, looked sickly and eventually 90% died. I managed to save about 4 out of 30 germinated from 100 seeds.

I've finally got the shelves I built lit up and they're working a treat. The lights are mounted up in the bottoms of the shelving trays and they heat through the shelf and keep the containers at 29-32deg c - All up the lights put out 100 watts. So that's 27 watts per shelf (2 rows of 1.25m).

5m x LED Strip (3014, 180LEDS/m, Lum 2070, 21.6W/m - Approx 90Lm/w, 5500k)

The soil mix I'm using now seems to be going well - I've done 3 lots with this mix and haven't had any problems and have almost 90+% germination and zero deaths - so I scaled up and planted 12 containers of various cacti, and I'm trying my luck with mugwort, silene capensis, calea z and a few other things I've had trouble germinating.

I chose this mix because the seed raising mix and coir have a slow release fert in them - my biggest problem is planting out, so this mix seems to be very tolerant of neglect, but may succumb to damping off if too wet.

- 2 cups osmocote seed raising mix

- 2 cups coarse sand

- 1 cup coconut coir

- 1 tablespoon dolomitic lime

I've had these containers in the shelves for 1 week running for 14 hours on, 10 hours off and they started germinating yesterday - so 6 days and they're off!

These are the shelves

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This is the dirt (I don't flatten it because I find the seeds fall into the grooves nicely)

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These are the lophs that are a little over a month old in the mix mentioned above

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Question: What is the max temperature cactus seeds can handle? On a hot day the temp got up to 34deg c

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Edited by IndianDreaming
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Is your mix you are using measured with normal cups? If so I would have thought that a tablespoon of lime was a lot. I haven't checked on the application rates so I could be wrong but It might be worth checking.

Your set up looks good and I will be interested in how your lights perform.

Are the temps that you are talking about the temp on the shelf or is it the soil temp. From my experience the air temps at around 35 deg is a great temp if you can hold it at that but you need to make sure your lights are not heating the soil from the bottom and cooking your babies. If this is the case you can add an insulator on top of each shelf and place your trays on top of that.

Wood will work ok if you want just reduce the temps a bit fiber sheet like blue board works well as it tends to spread the heat along the shelf more than wood. If you need to get more serious the you can use styrene sheet 10 mm is reasonably cheap and works well.

The other way to deal with hotspots on metal shelves is to lay a piece of mesh on each shelf and place your trays on that which lets air circulate underneath same can be done with heat mats and trays that don't have thermostat controls.

The biggest issues I am still having with seedlings is turning them red. I have found the hardest to get right are trich's and they also seem to be the hardest to correct once they have gone red. They also seem to totally stall while they are red.

I will make another post in this thread later with the setup that I am using now which has solved numerous issues that I was having.

Cheers

Got

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heres a write-up i did a while back for Gtarman, hope its of some use to a newbie

SOWING:

  • I reckon you need a tray that allows for minimum 3-4cm deep soil, too shallow and it dries out too quickly.

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  • I use 50/50 seived potting mix and fine pumice. By fine pumice i mean no big chunks, the grade i use for seedlings is 3ml.. If you can find pumice it would be preferable to perlite. The problem i have with perlite is that it floats in water, so after a couple months of you watering your seedlings it gradually rises to the top of the mix, partly separating itself from the soil mix...and then it crowds your seedlings. I'm sure you could use other types of crushed stone, grit of some sort. Some ppl make up special mixes for arios and other miniatures using various crushed stone, if you cant locate fine pumice, UTSE maybe.
  • I always pre-soak my soil before sprinkling over the seeds, i dont cover the seed at all, although i spray it lightly with rainwater and then the tray goes in a moisture chamber on the heatpad. I havent grown using artificial light but im sure it would be perfectly fine to lean a little lamp over them if your location doesnt have much natural light.

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  • Keep a spray bottle with rainwater (if u can) handy and spray atleast 2-3 times a week (maybe less if you are not using a heatpad) and then the secret to success has to be a little bit of fert at the right time. I use half strength seasol when they are about 3 months old, its amazing to watch. They almost appear to grow overnight!

HARDENING OFF:

  • At this size, roughly 3-4months old they are ready to be hardened off / taken out of the chamber and gradually exposed to the real world:

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  • When you do this, you have to do it gradually. Begin by taking the lid off, at first just for half a day at a time, then gradually work your way up to a full day with the lid off, ensure you keep up the watering during this time, you dont wana shock them!!
  • Once you have weaned them off the high humidity, repot them into bigger pots, be gentle! Expect a couple to die at this stage, they are still delicate and easy to mush if you're not being careful. Losses are inevitable at somestage or another, but for me its usually this one.

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  • When you have repotted them, slowly begin introducing them to sunlight. They should ideally be in a position where they get dappled sunlight for an hour or two each day, remember they are still very delicate at this age and will burn easily. Under the table in the greenhouse is one of the best positions I have found for this stage.
  • From here onwards, its really up to you to use your intuition and decide how much light they can handle and how much water they need. I have been very rough with some seedlings and put them in full sun too early, they will usually survive, but will turn purple and this will stunt their growth considerably.

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Got: Probably more like mug sized, 400-500ml - I think you're right, a tablespoon is a bit much, I was thinking of changing it to half a teaspoon in the last batch, but it looked like such a small amount when I put it in that I just plopped some more in.

The temperature is the soil temp - The middle top container has a temp/humidity probe in it that goes 3mm into the soil (you can see the wires in the pic above) - So the surface temp of the soil got to 34 - which I think might be uncomfortably high - I've read that 41 deg c is the point where you should panic - but with the lids on, at 34 deg, the humidity was 88% - which may help. I'm wondering if the 41 deg is the temp of desert sand without humidity.

It's too close for comfort so I'll be raising them up slightly with some wire mesh and will be able to tell within 20 or so minutes if that's enough. Thanks for the comments, I'd thought of mesh, but not the wood or foam, they're both great options if the mesh doesn't cut it.

Ceres: Wow - they're some really nice looking seedlings - especially at the hardening off stage. That's when my last lot went red, and yes, I put them out in sunlight that was too bright and they burned, very quickly. I'll take a photo and post it here so that people can see what the sunburn looks like - if you know what to look for you can probably whip them out of the sun before damage happens. It was about a 2 hour period at midday that burned a whole tray of seedlings :( I put them into some darkened high humidity shelves for a week and they have started to spring back to l life, although they'll be scarred.

Ceres: How do you get the seedlings out when transplanting? I've been using the handle of a fork to dig in beside the seedlings and pry them out...

Regarding Pumice: For Victorian members, I contacted Ausperl.com.au and there's a supplier of horticultural pumice in sizes of 1mm-4mm, 1mm-7mm and 4mm-10mm - 'Sure Gro' in Dingley Village. For Sydney folk, you can probably contact Ausperl as their main office is in Sydney. I'll let you know what the prices are etc.. when I contact Sure Gro if anyone is interested. I have the same, 'float to the top' issues with perlite and the scoria I have locally is too big.

Edit: Here is the temperature/humidity sensor I'm using, it was $2.50 from ebay - there's also dial type ones for $2.50 too - It's been an extremely useful gadget and works perfectly.

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Edited by IndianDreaming
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Ceres: Wow - they're some really nice looking seedlings - especially at the hardening off stage. That's when my last lot went red, and yes, I put them out in sunlight that was too bright and they burned, very quickly. I'll take a photo and post it here so that people can see what the sunburn looks like - if you know what to look for you can probably whip them out of the sun before damage happens. It was about a 2 hour period at midday that burned a whole tray of seedlings :( I put them into some darkened high humidity shelves for a week and they have started to spring back to l life, although they'll be scarred.

Ceres: How do you get the seedlings out when transplanting? I've been using the handle of a fork to dig in beside the seedlings and pry them out...

Yeh man, its soo easy to burn them at that stage :( i think the most important thing to do when you burn them is to give them a good drink! I have been shocked how quickly my plants have been damaged by the sun this spring, but you do seem to be able to enact some pretty effective damage control if you get them into the shade ASAP and provide a good drink straight away.

To pop out seedlings i use just whatevers handy, sometimes the back end of a spoon or fork, sometime a plant tag or pencil :)

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Transplanting seedlings

I use the hook end of one of these. :)

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They are called a Machinists scribe and are nice and light and easy to hang onto. The shaft diameter is only about 3mm.

To lift out individual seedlings I will use the straight end to loosen and then lift it out with the bent end. If I am doing a whole tray I use the bent end and work from one end to the other by loosening and lifting.

I would think any hardware ( $2 - $3 ) should carry them in the tool section or you could make your own out of some heavy gauge wire.

I also have these which would be the best 3 dollars that I have spent ( the kit even came with some labels) and they have cool names :lol:

The dibber is great for transplanting but it gets the most use for pere cuttings and the widger is just a handy little thing that gets used for all sorts.

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Cheers

Got

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first up, Thankyou everyone for this thread :worship: :worship: :worship: :worship: :worship: :worship: :worship: :worship: :worship: :worship: :worship: :worship: :worship: :worship:

I noticed a fellow SABer cant remember :bong: who used a layer of fine gravel on top of their seedling tray and I thought this was a pretty genius idea as even when bottom watering my seedlings i have had some issues with the sand/soil washing away from the base of them and i reckon it would also be good to help retain moisture in the growing medium as well.

But, i did wonder when would be the best time to add the gravel?? :scratchhead: :scratchhead: ....and would the seedlings be able to squeeze through a light gravel surface?? :scratchhead: :scratchhead:

ocd edit: maybe with the gavel there you wouldnt know if the soil/sand had washed away from the base of the seedling :scratchhead: :scratchhead: :scratchhead:

Edited by glimpse
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I had been adding a layer of course diatomaceous earth ( D.E., diatomite ) or similar after my seedlings were up. This was mainly to stand them up as many grew on there sides and even upside down but it was very time consuming.

Now I am putting a layer down on top of my mix and then sowing the seeds on top. This is working a lot better as most of my recent seedlings are all growing up the right way. :) The only thing I do after I have sown the seeds is to just knock any seeds that are sitting on top of the course covering down into the gaps.

I also have a different way of bottom watering now which I will explain in another post. The issues I had with bottom watering by dunking was because I use a lot of courser particles in my mix all of the fine pieces are the seedling mix and coir and they float up onto the surface which just defeats the purpose of my mix as the top is where all of the water ends up being retained.

This layer was put down well after the seeds had germinated.

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Cheers

Got

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They look like fantastic tools Got - I think with 12 trays in the shelves I'm gonna spend the $3 and invest.

So - a bit reluctantly, I've taken some shots of my dungeon dwelling Frankenstein freaks that suffered though my learning curve... Maybe someone can learn what not to do by seeing these, or maybe if you see yours heading in this direction you'll be able to rectify the problem before they get shunted to the dungeon of disasters...

Sunburn

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Etiolated

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Lack of nutrients - Left in the container too long - Put in too bright light - These are surprisingly 18 months old! They're still alive and I'm in the process of picking them out and transplanting them...

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The repair centre - these looked the same as above but are on the mend after re-potting, it'll take awhile but they will spring back.

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I learned a lot though these failures. The etiolated ones above all fell over like Got mentioned and I didn't know about gravel or pumice or scoria - I did try a few toothpicks as stakes but it was a futile exercise. Get onto any problems you notice early. I could have saved the sunburnt ones because I saw them gently whitening, then 2 hours later they were yellow and red, burnt and wilted.

The biggest thing I learned was what Ceres mentioned, light is a killer. I've now found the 4 sweet spots in my yard.

  1. Full sun
  2. Dappled shade all day
  3. Morning Dappled Sun for 2-3 hours
  4. Full shade all day with bright ambient light

4. is currently where all these little Frankies are living, 3. is where my latest hardened off cacti are, 2. is where I have the larger seedlings, 1. is for the big boys

Hopefully someone will see the signs of one of the above issues and be able to fix the problem before it gets too bad. :)

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IndianDreaming I have a few things that I have collected that I keep in my shed to deal with mixes and seedlings. Those little tools are really handy plus I have a range of cheap stainless steel sieves with varying size holes plus one one of the bunnings plastic ones. I wash and pre sieve all of my different additives that I use for my mixes and keep them in plastic tubs.

My seed raising mix that I am using now consists of Zeolite, diatomaceous earth, course sand, coir and seedraising mix with the organic parts only making up about 20%

One of the best things with using this mix is it has a noticeable color change between wet and dry.

I have been using a slightly different way of keeping my seedlings in humidity recently. This is not my idea it is from an exceptional Australian grower that posts at the Australian cacti forum and the cacti guide. I wont mention his name here but his posts are not hard to find.

Ok here goes. .

He has been using what he calls a wet box this is basically a clear plastic tub with a capillary mat in the bottom. I have been following his setup as close as I can and this involves starting the seeds in pots in enclosed propagation trays on a heat mat. Once the seeds have all germinated the pots are moved into the wet boxes.

Water is added to the capillary mat as required to keep the pots moister levels up. When it is time to bring them out of high humidity you just remove the lid and continue to water via the mat. Once you have been using the mats for a while you have a good idea about how much water you need to add to wet the pots through.

This system is very basic but what it has done for me is take a lot of the guess work out of watering as once the pots are wet through I just wait for them to dry and then wet the mat again wait a day and if the top layer of the pot isn't wet ( DE changes color ) add more water.

The hardest thing for me to get this set up was finding capillary matting over here. I started using chucks wipes which worked surprisingly well but I had to use a number of layers. I have ended up using the felt type material used for furniture packing (furniture removals )

The only other thing I had to do was drill more holes in the bottom of my pots. If the right style of pots are purchased then this would be unnecessary but I had already bought a few hundred pots so I drill holes. :)

Propigation box on heat mat

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Wet boxes

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The temperature is the soil temp - The middle top container has a temp/humidity probe in it that goes 3mm into the soil (you can see the wires in the pic above) - So the surface temp of the soil got to 34 - which I think might be uncomfortably high - I've read that 41 deg c is the point where you should panic - but with the lids on, at 34 deg, the humidity was 88% - which may help. I'm wondering if the 41 deg is the temp of desert sand without humidity.

I think from what I have read and experienced you are correct with those temps. mid thirties should be good but up into the forties I start to worry

I don't know how your lights are with there heat output but watch for hot spots. I have spots on my shelves that get a lot hotter then the rest because the ballasts from the lights underneath produce a fair bit of heat

Ceres

That was a great write up and it looks like you have your seed raising dialed in.

I will add more again later including some photos of the slowest growing Trich seedlings in the world. Yes I will also post pics of my early disasters.

Keep it coming guys and girls

Cheers

Got

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I'm new to cacti and have had mixed results with seedlings, been blundering my way through...

Too much light too soon and too much water seem to have caused the failures. Getting better at it now however. The following is my current method...

I've been using just comercial seed raising mix mixed 50/50 with fairly course grit from the river, washed and sieved to remove the sand particles and with a few pinches of ground limestone mixed in. This goes into a plastic container, about 1 litre, pop tops are good, as in the pic but the clip lock ones are better. Then a thin layer of straight seed raising mix sprinkled on top. This is Microwaved for a few minutes to kill any nastys before allowing to cool before wetting the mix with a sprayer containing Thriam fungicide and boiled rain water. Then the seeds sprinkled on top, trying to take care that they are spread more or less evenly followed by a spray of the fungicide again. Then into bright indirect light in the greenhouse.

Then when they have germinated (hopefully) I have been slowly increasing the time with the containers lids off untill they are open all day and then, eventually, open all night as well.

Every time without exception I have managed to over expose them to light to some degree.

Next I start thinking that they will dehydrate and die the instant the moisture level falls away so overwatering is the next problem. This leads, in extreme cases, to the root rotting off and me being left with a tiny (usually red from the mistreatment mentioned above) seedling that gets nursed for months and months before it almost always passes away in a tiny but final heartrending disaster involving much grief.

I think, for me anyway the main lesson in all this is patience. That and letting go enough so the seedling can do it's thing without constant interference... Usually watering it again.

Here is a pic of some astrophytums 2 weeks old.

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Edited by dawnbeaver
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just had my first batch of seeds come up, simple setup - seed raising mix + washed sand (don't know ratio about 70-30?) wrapped in home brew heater (those flexible rubber ones) popped next to front window in a sealable container and sprayed once with mancozeb to kill the mould that was growing. seems to be reasonable germination after about 1.5 weeks? anyway one side is nice and green the other side less so, looking decidedly white actually. they should green up over time yes? they're only a few days old i'd say.....

they're ayacucho x something and either conxtig or tigxlen i can't remember , thanks to whoever gave me the seeds by the way :)

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so is it true that extreme high/low temperature fluctuations really assist germination? i can see how they would adapt to this in their natural environment, some places i read yay some say not to worry about,

what say ye?

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so is it true that extreme high/low temperature fluctuations really assist germination? i can see how they would adapt to this in their natural environment, some places i read yay some say not to worry about,

what say ye?

I say that some seeds require a temperature flucuation to set them off while others do not.

Which are which is another story...

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Hi everyone,

A few people in this thread have made reference to "bright" light having a negative/damaging effect on cacti seedlings, particularly newly germinated cacti.

This may be a silly question, but I'd like clarification on what is meant by "bright light" causing damage?

I can understand the damaging effect of UV from sunlight on newly germinated cacti or any other plants for that matter. By "bright" light are people referring to sunlight, which could essentially mean the damage is caused by UV. Or is light intensity itself a factor that causes damage, and if so, does anyone have a brief explanation why? I've been reading for the past few hours on the topic but I can't seem to find a solid answer. It appears to be quite a complex topic.

Previously I've germinated cacti seeds using indirect sunlight on a window sill, and I've also used a simply CFL cool white bulb (perhaps a phillips 24W) with success.

However I've recently purchased the following Phillips 80W CFL to play around with: https://simplyhydroponics.com.au/component/k2/item/476-compact-80w-fluoro-hydroponic-light-kit.html

Specs:

  • Special coil design to concentrate light output
  • Very high lumen per watt ratio (66 lumens per watt)
  • Reaches optimum light output in less than three minutes
  • Wattage and lumen output remains constant during operation
  • 6500k
  • Guaranteed 80 watt with 6400k

Would you class this light as to bright for germination and the initial stages of growth for cacti or other plants for that matter? Would this light cause damage and as such, is it more suited to cacti or plants that are more established?

Thanks in advanced.

J.

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Sorry to bump an old thread but does anyone have an answer for the guy above me?

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They just arent used to direct sun light as older seedlings. Direct sunlight not only inhibits germination and takes too much moisture from the soil. It can also cause sunburn, which will kill freshly germinated seedlings. Older seedlings are fine if slowly adapted to direct sun light. There is no max temperature or way to say how much is too much for a certain batch of seedlings. It greatly depends on how old and healthy those seedlings are.

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Artificial light might be less dangerous because I never had sun damage from a lamp. Just heat damage. It´s probably that the sun can produce a lot more intense UV rays than those lamps. Just make sure to avoid heat damage (eg HPS lamps tend to get really hot) but as far as I know, I feel like the lamp isnt that of a problem. Cactus seed need diffuse light to germinate and the only thing I´d avoid as the plague is putting them in the direct sun. I guess it´s hard wired into their DNA not to germinate when left in full sun, because the chance of survival is not great. But I´ve seen great growth rates from seedlings that were put under lamps very early on. I use a LED lamp to overwinter cactus seedlings and it does not cause UV damage. So if the CFL damages anything, try the LEDs.

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What LED lamp do you use EG? I keep looking at LEDs but don't want to waste my money on a bad LED.
Am going to be buying a new light soon, was thinking of getting this one:

http://www.ebay.com.au/itm/251333590174?_trksid=p2060353.m1438.l2649&var=550277822353&ssPageName=STRK%3AMEBIDX%3AIT

One more question, anyone have any idea what causes white spiderweb like mold? It doesn't seem to spread via contact? Or is it just the seedling dying and rotting?

V420

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