I have always assumed that when I am told to plant a seed any significant depth below the surface - say, 1/4" more - I can deduce that it does not need light to germinate, and so I can, if I am low on well-lit places, germinate the seeds under a couch, in a closet or whatever (yes I know that I have to check regularly for germination). Does anyone know if my deduction is or is not valid?
A relatively small number of species do require light to germinate, and for those, you'll see instructions such as, "do not cover", "sprinkle seeds on surface", "surface sow", or, simply, "requires light to germinate". If you are interested in this subject, try to acquire Dr. Norman C. Deno's publications. He's studied seed germination in incredible detail, and his works are absolutely fascinating to read. The publications are available from the author, and from NARGS. Since you are from Vancouver - something of a horticultural hotspot - perhaps there is a horticultural library at one of the gardens (UBC?) from which it would be possible to borrow his works? EDIT: Actually, I should have said, "Your deduction may be valid for the species you are germinating, providing those instructions are well-researched." (Okay, that's assuming the vendor is actually knowledgeable.) Your statement is not a valid generalization, however. My point was that some species do require light, though possibly not the ones you have experience with. For those that don't require light, I have done the same - that is, put them in a dark spot, and move them to light after germination.
Karin, I'm not sure if your question is aimed at me or at the original poster. Deno's experimentation was conducted scientifically (he's a professor emeritis of chemistry at Penn. State), and is reported statistically, so I believe it's as representative as that particular set of data allowed. (I use his findings every year for starting perennial seeds, but have never attempted to duplicate any of his experimentation - I admit I don't have the discipline nor probably even the space to do so in a way that would have any statistical meaning.) He found there are a number of species for which a photorequirement (i.e. absence of light) is the only mechanism that delays germination, and also a number of species for whom germination is totally blocked by light. He was able to group the data into 7 categories of reaction to photoeffects - the two I mention here (an absolute requirement for light, and an absolute requirement for dark) are the endpoints, so to speak of the spectrum of how seeds react to light. Anyway, I highly recommend reading the publications! PS When I attribute this all to Deno, that's not really correct - he cites an extensive list of references on seed germination. But the beauty of Deno's work is that the previous work is summarized, added to his own extensive research, and packaged in a form that is imminently readable - scientific yet approachable!
Sorry, AB, my question was aimed at the OP and not at you. The reference you cite does sound good, though actually your further response and the edit to your first post clarifies its applicability to the question that was asked - thanks! I was curious whether Soccerdad had tried dark germination already or not.
A few years ago I put some plant trays below a sofa, but with variable success. I used to start seeds in the 4" gap between the top of the fridge and the bottom of the above-fridge cupboards, very successfully, which I attributed to the fact that this will be the hottest place in the house (sort of one of the basic laws of thermodynamics, for those who recall such things); I do not think that any significant light could have got there. I germinated some strelitzia seeds in a closed cupboard a few years ago. My reasoning is this: If a seed is to be planted say 1/2" below the surface, the light cannot get to it - I assume, anyway; I do not know how far into typical moist seed-starting mixes light (say, sunlight) will penetrate, but the distance is clearly finite in any event. If the seed germinates when light above the soil does not reach the seed, it seems to follow that the seed cannot possibly need the light-that-it-does-not-perceive, and so one does not lose anything necessary by putting the seeds in total darkness.
There's a very widespread belief that bottom heat and temperatures above 70 deg F are beneficial for starting seeds, and it's very difficult to convince people otherwise. According to Deno (Second Supplement to Seed Germination Theory and Practice), Henry M. Cathey studied the topic extensively and published his findings in 1969. (Hmmm, 40 years of heat mat sales in the meantime...) He studied germination at 5 degree intervals from 50-85 F, and found that it was usually optimum around 70, and markedly lower at the ends of the range. Deno's studies drew the same conclusion - that temperatures above 70 are neither useful nor desirable, with few exceptions (well, two). He concludes that the practice of using bottom heat arose back in the days before central heating (when houses were kept much colder than today) - and is therefore no longer necessary for that application - and for use in cold greenhouses, where it would still be useful. So, the value of bottom heat turns out to be another one of those gardening chestnuts, that just gets repeated from book to book by lazy authors... PS Hmm, I did take thermodynamics, and, even ignoring the evidence above, I can't say that any link between the laws of thermodynamics and seed-starting is jumping out at me, exactly.... LOL!
The laws of thermodynamics only tell you, in this connection, that the area around the fridge will be hot. Unless Maxwell's demon lives in your house.
I often pondered the same thought that light is not necessary for germination but mosture and heat. That is until there is certain amount of evidence to it's need ( i.e. vegatation) and then the light is best filtered (shaded) . The germination is the easy part, getting it to becoming a successful transplant is the hard part for me.
