Soak the rose seeds overnight. Then in the morning strain the seeds of and then - wait for it - place into a blender with some more fresh water. Turn the blender on to LOW and wizz for a few seconds in order to remove most of what is left of the pulp. You may lose a few seeds here but you can always skip this step - especially if you are short of seed.
Alternatively you can clean the pulp from your rose seeds by spreading them out on a clean cloth or towel and scrubbing over them with a suitable brush. Be aware that this can end up being quite a lot of work.
From this point, professional rose grows tend to chill their seeds from between six to ten weeks before planting as this will encourage germination. If you leave them in any longer, is has been known for rose seeds to germinate in the fridge!
The most popular method of refridgeration is to place your clean, seeds on to a piece of good quality, damp paper towel. Fold the paper towel over a couple of times and then place into a seal-able plastic bag. This can now be left in the salad compartment of your fridge.
Rose seeds collected as late as November - and possibly as late as December and January in warmer climates - can be planted as soon as they are retrieved. However, if they have been chilled then they can be sown in early spring. If there is a risk of frost then this will need to be done under protection.
Allow the soil to drain off then move the pots/tray into a warm and sunny position. Place a clear cover - such as a sheet of glass or perspex - over the the pot or the pots/tray and place in a cool yet sunny position. If there is no risk of frosts then the containers can be placed outside into a cold frame.
Keep the soil moist and after six weeks or so your rose seeds should begin to germinate. As soon as you seed the seedlings emerge, remove their clear cover. If the seedlings are in a cold frame then the lid can be left open during the day - don't forget to shut it at night. The seedlings will continue to sprout while the weather is cool but growth can be arrested if the young plants get to warm!
Once the rose seedlings are a few inches tall then can be potted on either into 3/4 inch pots, or if you are feeling brave then can be planted directly into a prepared bed outside. From there it will take just three years to reach maturity.