Not sure what you mean by raspberries that you mow down in the fall. All raspberries have biennial canes, they grow leaves and get tall in the first year then grow short, lateral shoots with fruit in the second year. The canes die after fruiting and should be cut down then, which usually means you are only cutting down half the canes.

If you are mowing all the canes every year, you are cutting down the first year canes so that they will be very short the next spring and will not produce as much fruit.

There are "everbearing" raspberries that produce a summer and a fall crop. They produce a fall crop the first year and a second crop the next summer. If you cut them down after the fall fruiting then you will miss the next year fruit.

See the link below for detailed discussion of fertilizing, mulching and pruning.

Here is a link that might be useful: Growing Raspberries in Ontario

In the TV show Garden Smart, they featured a raspberry farmer who had a variety that he described a mow in teh ground type. Here's description of this fellow's practise. Please note though that these are areas that are higher than zone 5 and therefore things may be quite different in your zone which has a shorter season.

"Adam Hausmann is an organic berry farmer. Often when thinking of berries one thinks of fields filled with strawberries, raspberries and blueberries. But these can be easily grown in your backyard.

Adam especially likes raspberries. There are 2 types of raspberries, the summer and the fall bearing variety. Adam recommends the fall variety because of their ease of care, they are simple to grow. Pick a small corner of your backyard, a fence line, a hedgerow, whatever it might be and till up a small area. Plant the raspberries a foot or a foot and a half apart, mulch them in and you should have fruit for 15-20 years with proper care. Adam heavily composts raspberries because they're heavy feeders. He shows us foliage growth on the plants, because of this and the fact that they will grow to 5 to 6 feet high, they need a lot of nutrients, a lot of nitrogen, they also need a lot of energy to fruit. So around planting time every season he integrates an inch or 2 of compost. The compost slowly integrates itself into the soil, it adds organic matter, nutrients and with rain and time it percolates down into the roots throughout the season. The soil becomes healthier, it holds more moisture which will get you through drought periods better, it keeps disease away because you have healthier canes and healthier plants. He recommends that any home gardener start a compost pile, it will be helpful for not only raspberries but vegetables and flowers as well. Adam has installed a drip irrigation system and puts mulch on top of that. He has 300 foot rows, the drip irrigation emits water roughly every foot or so. This ensures that every plant receives ample water - a gallon or 2 per hour. He then adds mulch. Adam uses either straw or grass clippings, both work well as will sawdust mixed with horse manure. This is another way to add more organic matter into the soil. In Vermont, fall raspberries start fruiting in mid August and last until early frost. It is a great producing plant that yields fruit for months. He has friends in the south that have these plants producing until Thanksgiving, if not longer. If you grab the cane it has little thorns but they aren't very sharp, almost a soft spine, not like a blackberry bush. Because of that they're great for kids, children can easily reach the fruit, which grows on the side, it's east to pick off and nobody gets poked. There are red raspberries, as well as yellow raspberries. Adam has 3 different varieties of reds and a yellow fall bearing variety that comes on a little later than the reds. All are incredibly sweet and delicious because they have time for the sugars to mature. The berries are large, thumb size, not as crumbly as the summer varieties and they melt in your mouth. After harvest Adam lets them die off by frost. This gives them a chance for the carbohydrates to go back into the roots. In late winter or early spring HE MOWS THEM TO THE GROUND. You can use a hand clipper but it's easier to use a lawn mower when mowing to the ground. Remove all of the canes left over, this will eliminate a lot of disease and keeps the plant healthier. Raspberries are easy to maintain, a great crop to grow in your backyard. All you do is add some compost, mow them down once a year and they will create a beautiful hedge to fill out an area. Keep them contained with raised beds or some edging but other than that it's pretty simple. "

Thank you Ianna, good tips.

I have figured out that I mowed the berries down in the spring, which in itself wasn't too bad but I waited too long,
I mowed (cut) some very early in the spring, these ones have grown and are bearing fruit, the ones I mowed about 2-3 weeks later seemed to take a long time to get going and now look like they will bear but our season wont' be long enough to ripen.
So my leason is not to neglet my fall work and mow or cut them back in the fall; then they will do just fine.

Check out the information on this site.

Clayton

Here is a link that might be useful: Good Information