Many people have asked me this over the years, so I thought I would share it here.
I don’t have a specific method or medium I prefer, but I find that the most common recommended way, with sterilized medium and covered pots does not work for me in my climate, where the temperatures are usually hot. Any covered pot gets fungus here very easily.
Instead, what I do is:
Rinse the medium out thoroughly with as much low TDS water as my budget and patience allows. Medium is usually either very good quality NZ sphagnum with a top layer of finely chopped sphagnum or very well rinsed cocopeat. I don’t heat sterilize it in any way. Depending on weather conditions and if my collection has any plants with fungal problems, I may add some trichoderma to the final rinse.
If I have used trichoderma, I fill the seedling pots and let them sit for a day or two before sowing seeds – lets the trichoderma get a bit of a headstart (or at least in my imagination). Alternatively I may use a fungicide. Neither is necessary if your growing conditions are healthy and you aren’t seeing any fungal issues around.
I sprinkle the seeds on top of the growing medium and give them a good misting down, so that they stick well to the medium. If I have time, I may go over the pot with a magnifying glass to look out for any seeds stuck up in the air without contact with the medium and just press them down. (nothing esoteric, plain logic)
I usually place the pots where they get misted on from the misting system. Alternatively, I may spray them down if they start to look dry-ish. This can be irritatingly often in hot/dry weather, so misting system is better. I also have small bottles with nozzles for when they aren’t under the misting system and I lack the patience to keep spraying. Whatever you use, do it carefully enough that you aren’t washing the seeds into the growing medium – they need to sit on top.
I don’t stand seedling pots in water. I find this encourages algae.
I don’t cover the seeds to maintain humidity, which is usually adequate due to the misting system (I don’t cover them even if the misting system is switched off). Personally, I have not found high humidity to be a big deal for germination, as long as the medium is moist enough.
Sometimes nepenthes seeds do get fungus and it is not on the medium – it is on the seed itself. I am not sure what this is, but I suspect it grows on seeds that are already dead and does not appear to spread to other seeds. If paranoid, maybe spray diluted hydrogen peroxide on the seeds that seem to have the fungus – I have done this, and I have not done this and I can’t honestly say the results were much different beyond the fungus not bothering me visibly when I did.
If you cover seeds and get fungal problems, in my view, not covering them is better. If you MUST cover them for whatever reason (I’ve had problems with byblis liniflora seeds crowding out neps, which could have been prevented by covering), I would suggest leaving the cover at least slightly open for ventilation.
Doing this or similar usually leads to germination any time between two weeks and a month. Some seeds take longer. Maybe 2-3 months. It is very rare for me to have seeds germinate after that. If seeds have not germinated in three months, I usually wait for a season change to see if that does the trick. If it doesn’t, I throw them out.
It is quite common for nepenthes seeds to be unviable and if your seeds appear to be pest/contamination free, but still not germinating…. sometimes it is not your fault. Generally, if you see the seeds clearly, it is worth a shot to keep giving them good conditions and waiting.
Newly germinated seeds are usually tiny and crowded in the pot. I avoid transplanting them for as long as I can. At least a year if possible. If they are very crowded, this may not be possible, in which case, I think it is better to transplant them as soon as possible – before the first two true leaves and while they barely have any roots to prevent root damage.
Overall, for seedlings, I think they grow just fine crowded up unless it is too crowded and there isn’t space to grow or some seedlings start getting stunted because of bigger ones covering them. Apart from that, simply being close to each other does not hurt them. In fact, I think it helps them maintain a microclimate better.
The big fertilizer question: I fertilize seedlings. I use orchid fertilizer. Too much is bad news. The seedlings are tiny. They don’t need a lot. Very little (1/4 of recommended strength) and as often as once or twice a week is better than more concentrated. If in doubt, don’t.
Also one BIG DRAWBACK of fertilizing seedlings: Fertilizer will encourage algae. This will reduce germination in seeds that have not yet germinated. Unless you transplant seedlings into separate pots for growing after they germinate, fertilizing may decrease your overall germination if algae cover up the ungerminated seeds.
This is a rather spontaneous post, so if there is something I have missed, do feel free to ask. Or better still, share how you germinate nepenthes seeds.