Methods for Removing Seeds from Hips.
Cut hips in quarters to remove seeds. Do not be afraid of damaging the seeds, which are extremely hard. A small steak knife that has a sharp pointed tip is a good tool to use when extracting seeds. The blade can be used to quarter the hips, and the sharp tip is handy for prying out the seeds.
If you have a large number of open pollinated hips, you may want to save time by using a kitchen type blender (with dull blades). One temporary way to produce dull blades is to wrap tape around the normal blades (such as stainless steel tape with an adhesive backing that is sold for repairing rust spots on car bodies); other options are to bend the blades so that they are more perpendicular to the direction of rotation, file the sharp edges off of the blades, run the blender with a sand solution until the blades are dull, or to simply replace the blades with homemade blunt blades. A blender that has a metal to metal contact between the motor and the blade unit is recommended (such as an Oster - plastic or rubber contacts tend to strip under the heavy load of rose hips) . Add water to the ripened hips and blend at the lowest speed. To remove the pulp, use two round wire kitchen strainers. The first with relatively large openings is the type sold for cooking French fries in oil. The second is a standard kitchen strainer that has relatively small openings. Place the large screen strainer on top of the small screen strainer. The place the ground up hips in the large screen strainer and press on the pulp with the back of a large spoon. This forces the seeds and the mashed pulp through the large screen. Then direct a stream of water through the pulp on the fine screen to remove as much small pulp as possible.
For an important cross you can use tweezers to hand pick the seeds from the remaining pulp. For open pollinated aged hips, you can try putting the pulp and seeds together into the enzyme soak described elsewhere (a complete cleaning may not be necessary, one can often get a very rapid germination from these combined seed - rotting pulp batches. One can only speculate concerning the reason for this rapid germination behavior: possibly the enzyme soak accelerates the decomposition of the germination inhibitor chemicals in the pulp, and / or the enzyme soak accelerates the release of ethylene which is a germination promoter.).
Except in the above case where the rose hip is well rotted, make sure that the seeds are clean of any fleshly material from the hip as the fleshly material will contain germination inhibitors. Here again, the blender is useful as a short run in a sand solution will clean the hips. One can prepare a second blender container for this use by using epoxy glue to mount a screen above the blades. The screen weave should be large enough to pass the sand but too small to pass the seeds. Add the sand - seed - water mixture to the modified blender container. The sand and water will pass through the screen while the seeds will remain above the screen - protected from the blades. For this step the blender is run at high speed and effectively acts as a "sand blaster". Alternately, you can use a plastic scrubbing pad and a little abrasive scouring soap to clean the seeds.