blomma wrote: Pfg, glad you are passing on the Deno method.
Domehomedee, the seed mentioned that need flunctuating temperature is because they have double dormancy like iris seeds and need it to break dormancy and sprout.
Here is how I sprout Iris seeds, which can be used for any seeds that require fluntuating temps.
Store seeds in the fridge until you are ready. I start my seeds 3 weeks prior to winter weather---between October and November in my zone since I have many cultivars. Begin the process by soaking the seeds over night in a container filled with hand hot water. Allow to cool. The seeds need to remain in cold water for at least 3 weeks. Change the water out daily using a strainer to catch the seeds (to prevent losses). No nicking is necessary. This soaking and rinsing treatment is to remove the seed germination inhibitor present in the seed or seed coat. Outdoors, the fall rains and melting snow in winter do the same thing over a 3 to 4 month period.
If you have only a few cultivars the method below is a quicker way to remove the inhibiting factor. It cuts the soaking time in half since each time you flush, the inhibiting factor becomes less.
Buy nylon knee highs---cheap in Walmart. Put the seeds in the knee high so that they'll end up in the foot then take the knee high and a tag and use a mideum binder paper clip to attach the tag to the open end, or tie a knot.
Remove the top from the toilet tank. Drop the knee high into an area of the tank where it won't interfere with the moving parts in the tank. Be sure to leave the open (or knotted )end outside the tank. The foot part or closed part is put in the tank. The tank top and the binder clip, or knot, will prevent the sock from sinking into the tank and get flushed.
I use plastic shoe boxes with lids---inexpensive from Walmart---to sow seeds in. Drill or burn drainage holes at the bottom. After soaking, sow the seeds in pre-moistened potting soil 1/2" deep. I cover the containers and leave them out all winter long on North side of my house. An unheated shed or garage works also. Iris seeds require 12 weeks of less than 40 degrees temperature that fluctuate to break dormancy. They will sprout during spring when temperature reaches 55 to 70 degrees.
If you live in a climate without cold winters, the fridge can be used. It will just take a bit longer to break dormancy.
When the weather begins to warm in the spring, remove covers. As the seeds sprout place where they will receive morning sun. When large enough to handle, pot them up. I use 3" foam coffee cups with holes pierced at the bottom. Here in Wyoming, May 31 is the safe time to plant in my nursery.
Iris seeds can be stored in ziplock bags and placed in the crisper in the fridge. They will remain viable for years.
Below is my bin full of iris seeds planted in plastic boxes. Dec. 2011.