Blackberries fruit on 2nd year wood, so if the canes are not making it a 2nd year, no fruit. Raspberries can fruit twice on each cane, if fall bearing. If summer bearing they fruit once on 2nd year wood. Pruning is different for summer bearing and fall bearing types. 2 ways to prune fall bearing.
Every year I put compost around my blackberries and raspberries. I also fertilize monthly with a soluble fertilizer, but also put out organics in the spring. I fertilize at 1/2 strength twice a month.
Blueberries take a few years to produce. Ph has to be kept at proper levels. Heavy feeders too. I don't use compost but organic fertilizer meant for blueberries like cottonseed meal or Holly-Tone. Plus add sulfur as needed to adjust PH. All plants are mulched and kept from drying out. Blueberries especially like moist soil, not wet, moist.
All these plants need lot's of light, like all day.
If these conditions are being met, and they are not producing, not sure what's going on?

ok, thanks. i think i have fall bearing raspberries. there is no fruit on them earlier than september. do i need to prune them any way now? my wife was just telling me that there was actually some flowers on blackberries one year but never turned into fruit. i will be fertilizing as you suggest. my blueberries have all day sun, raspberries and blackberries get a lot of sun too, but they are shaded late afternoon.

The blackberries and raspberries can tolerate some shade. So you're good there.
Two ways to prune fall bearing, sometimes called everbearing.
Prune cane down to the ground after fall harvest. It makes it easy and usually fall harvest is big. It does sometimes take a couple years for a decent harvest. I do have one raspberry going on 3rd year with no fruit yet, the fall crop was so late, no yield. But once raspberry settles in, it will produce earlier.

2nd pruning method and btw, this is what i do. It's harder to keep things straight though.
After fall harvest cut upper 1/3 of cane off, the part that had fruit, only the top does, cut that off, leave lower 2/3 cane. The following summer this lower 2/3's will fruit. Cut them off at ground level after summer fruiting. New canes will grow and fruit in fall and repeat the cycle,
The problem with this method is the 2nd year canes called floricanes can block the new 1st year canes called primocanes.
Some plants produce 2 good crops, others do not. I would try this method, and if it seems a problem, go to method number one.

Here is a photo. On the left are new primocanes that will fruit in the fall. On the right are floricanes fruiting in summer. This cultivar is the yellow raspberry "Fall Gold". It produces two good crops. Those floricanes on the right are actually just 3 canes. There is one primocane behind them.
Hard to see but ripe berries are on the floricanes, and berries are forming on the primocanes. Photo taken 2013 07 16.

Don't forget that the buds may have been affected by the horrible spring we had last year. 7F on April 10th! I have over 50 trees and berries growing and all I got last year was a handful of Surefire cherries.

I have planted blackberries and raspberries this year and have protected them from the cold. No berries yet.

I was at Timberline Nursery last year and Kelly Grummon (sp?) said the best way he has found to grow blueberries here is to purchase a bag of sphagnum peat moss, poke holes in the bottom, and then bury the entire thing. Then you plant your blueberries in that and use only rain water to water. Also, I bought southern blueberries that are cold-hardy. I can't recall the name right now but they can tolerate less acidic soil.

thanks mhgirl, i planted my bluberries almost the same way. didnt keep the bag though. i dug large holes and filled with peat moss. i can tell it really helped the bushes as they grew like crazy that season and next one too. its just i only found 4 berries on one of them and none on other one. might try peat moss bag if i dont get any fruit this year.

We had poor blueberry harvest in 2013 due to an overcast and very wet spring. The weather seemed to keep the bumblebees holed up, so the blueberry flowers did not all get pollinated. I was expecting to harvest 4 or 5 gallons of fruit, and I ended up with one gallon. To be successful with blueberries, they need to set flowers in the spring, and the bees have to emerge and pollinate the flowers. We also have everbearing raspberries, and these plants begin to flower in July, with ripe fruit in August, through October. Raspberries seem to do well with morning sun and afternoon shade. They also require bees for pollination.