Most sites indicate seeding oats and clover at about 50 pounds per acre. Oats are not a particularly good winter cover crop since they tend to die at low temperatures, although they may be a fair nurse crop for the clover. The radish would be sown at about 10 pounds per acre.

Can't help with the rates since I forget and go with specific plates in my Gardenway planter anyway. I've used oats planted here in mid-Sept. for an excellent cover as they will pull up residual N from the preceding veggies, grow lots of tops for cover and then either frost kill in the Fall or get mowed down if they try to go to seed. The result is improved soil tilth in the following Spring and substantial soil surface cover from Fall through Spring cultivation. Planting too early yields a stand that goes to seed, too late and not as much cover as I'd like so, mid-Sept. works best here.

This year I decided to plant oats as a nurse crop for Berseem clover fro the first time. The clover and oats were planted about 2 weeks ago as that was supposed to be the best time for the clover though a little early for the oats. the clover was planted in roww on 10" centers with the oats alternating on 20" centers. Everything has come up well with the oats really humping it. the clover seems to be poking along pretty slowly so, not too sure how much cover it'll provide for the Winter. The clover hopefully will be well established to get a good fast start come Spring.

As for the radishes, my only experience with them was this Spring, they got a fantastic start but too many weeds got going amongst them so I mowed the whole mess down and kept the weeds cultivated for the Summer. Maybe a much higher stand density would have worked better to smother the weeds, live and learn ya know. Good luck and don't stop trying different stuff for your area.

And here's the cover crop now, the pic soesn't do it justice, it' a beauty! Kim, it's fine with me that the oats die as they will still do their job. If I wanted something that would survive Winter I'd plant a rye. Crap, can't get the pic, oh well.

The purpose of a cover crop is to provide some means of aiding in keeping soil in place, preventing soil erosion. Oats, because they are killed by freezing weather, do not provide that although they could be a good green manure crop at this time of year if turned in before they are killed off.
Leaving soil bare and exposed to the ravages of the winter winds and rain is not an environmentally sound thing to do and is one reason why a winter cover crop is planted.

If the oats (or any cover) set a good enough root system and a bit of a canopy in your area it doesn't matter if it's alive or dead.

Cover crops don't need to be living to do their job. Some prefer fast-growth/quick-kill crops leaving their stubble in the field.

Kim, erosion control and mopping up and recycling nutrients for next year's crops are my goals for a cover. The oats do die after a hard frost (not yet here) but have established a great deal of growth above and below ground by that time. My oats are now approaching 2 1/2' tall and are planted dense enough that as the killed tops lay down they will totally cover the ground with a solid mat. The extensive root systems make for beautiful tilth the following year. It took me a few years to figure out when and how to plant oats to achieve my goals.
One handy plus to the dead tops the following Spring, if it has been wet and I want to plant a row of early crops like cabbage or broccoli I can very easily rake the dead tops off the strip in order to allow the soil there to dry quicker. Those tops get composted or used as mulch later.

Temp hit 5 last night and the oats are still green and standing, takes about 0 deg. to finish them off. The wind driven snow a few nights ago got caught in the stand nicely, a big plus for this arid place.

This may interest some here.

Here is a link that might be useful: Radishes for cover crops

That is of course interesting.

Many of the grain farmers with cattle here raise turnips or tillage radishes in the Fall and turn the cattle out to graze the tops.

kimm, That is a nice video of Joel Gruver's work. I sow the radishes in a random manner that covers all the soil......love them.