I'm pretty new to the world of Nep growing- but like most of us, I've wanted to germinate as many seeds of as many varieties as possible. However, after searching all the forums for many hours, the first thing I found was that the information out there is quite disperse and a lot of it is hotly debated.
So I've taken on board a lot of the advice out there and spent a lot of time this year playing around with conditions and seeds, trying to get seeds to sprout. The big breakthrough for me came when our friend Delwin sent me 20 seeds of the N.veitchii Bario highland form- this was top of my list of Nepenthes I wanted, so I ended up obsessing about getting these to germinate. I checked on the seeds every day. Sometimes several times a day. Then kept fiddling with the precise conditions until I had some success.
So- apologies to everyone who has been germinating seeds freely for years- but I thought I'd add my own experiences. I have a feeling that all of this is going to be incredibly obvious to everyone who has germinated Nep seeds before, but, honestly, I've found this information hard to find and confusing when I've found it.
Here's my complete guide to seed germination for beginners.
1. Start with fresh seed. I have a feeling that this is the one thing that causes the most disappointment amongst beginners such as myself. As a generalisaton, old seed just doesn't germinate. No matter how it's been stored, even at 4 degrees C, seed that's been stored for more than as couple of months won't grow. (Well, sometimes it might. But that would be described in a form post called "seed germination for experts".)
Also- seed from dodgy dealers on ebay doesn't grow. There's a couple of reputable sellers out there who sell freshly seed. It germinates freely. I've always believed that Nepenthes seed is very hard to germinate- but I think it's because I've been using old dead seeds before.
2. Sowing medium. Everyone has their own mix- I think the conclusion is that many different compost mixes are equally useful. People use sphagnum moss, long-fibre sphagnum (dead, dried moss), a pet/perlite mix or some combination of these. The critical factor is that it's well drained.
I was using a mix of Shamrock Irish moss peat (25%) and perlite (75%) until I made a horrible, horrible discovery. It works brilliantly for most species- but sometimes it doesn't work at all. With my valuable veitchii seedlings, the ones that germinated in areas of peat did fine, but ones that germinated in contract with perlite simply stopped growing before the cotyledons were released from the seed coat.
So now I still use the same mix of moss peat and perlite- but put a thin layer (5mm) of moss peat on the top of the mix. That's solved the problem.
There might be an explanation in the icps article below (advanced reading, but one of the most useful): some seedlings of some species might be sensitive to impurities that leach out of the perlite:
I had soaked my perlite in rainwater for a week- but still it seemed to poison emerging seedlings, although perlite seems fine for the majority of species and slightly larger seedlings. Not quite sure what to conclude here. Experiments are still in progress.
3. Temperature. This one is easy. Germinate everything in lowland conditions, ie temperatures somewhere between 20 and 30 degrees.
4. Lighting. There's been a lot of debate about this on various forums. Do Nep seeds NEED light to germinate? I don't think so. Do they germinate better if given bright light? Yes.
Well, that's what I think. I'll share my experiences....
Again, this started with my valuable veitchii seeds. Three other people who were germinating the same batch of seeds were getting 80% germination. I was getting none- despite the temperature ranges being similar. I realised that I was growing mine in subdued natural light- the other were growing theirs under bright artificial light.
I immediately went out and splurged twelve pounds on a pair of 9w fluorescent lights (the sort that are designed to go under kitchen wall units to illuminate work surfaces... they even link together!) I put these 2 lights slightly over the top of the electric propagator that my pots of seeds were sitting in, so that the seeds are about 15-20cm away from the lights.
With such low wattage, it makes very little difference to the temperatures- maybe it raised it a couple of degrees, no more.
Suddenly- and I mean within a week- I was getting radically different germination results. I got a flush of germination of 10 different species. Before the addition of lights, I had got one or two seedlings germinating per pot. With lights, within a week or two, I was getting ten times that. Pots where I had a few happily growing seedlings suddenly had a new flush of germination. eg in one pot of Viking seedlings, I'd had an initial flush of 16 seedlings from a seed pod- and no more since. Given bright light, I got a second flush of another 20 seedlings.
Some reinwardtiana seeds which had sat doing nothing for 3 months- 3 seeds sprouted within the week. Some albomarginata that had given me 3 seedlings before, gave me additional 8 seedlings after a week of bright light.
(And my precious veitchii, I've now got 6 seedlings at the cotyledon stage- with more germinating freely now.)
I hope that sharing my experiences here might spark some debate about what works for others. What I've written here is a case of "this works for a beginner like me", so I'm sure a whole heap of additions from those of you with more experience would be very useful for everyone who's struggling to grow Nepenthes from seed.