I know it depends on which direction your ground slopes(that is if it slopes) but I'm wondering if there is any benefit to orientating your rows/beds so that they run either east to west, or north to south?

Things to consider are the slope aspect, drainage and airflow. If the slope is steep, then try to keep rows relatively perpendicular to the slope. Eliot Coleman wrote in his book "The New Organic Gardener" that folks who in the southern parts of the US shouldn't be as concerned with orientation of garden rows. Further north he recommended orienting them East West to take advantage of the fact that the sun is less direct and there will be less shade effect.

N-S.
I find it really hard to describe in person, so in print's rather hopeful
If I can't manage it, hopefully someone can explain better.
Here goes...Because the sun arcs from E to W over the day, ideally the beds are orientated for maximum sunlight to fall on each plant.
For eg: if the beds go E-W, the plants on the 'inside' of the bed will suffer from lack of light, as the first couple of plants will block it, This is especially likely in winter, when the sun's arc is very low at midday.
Another reason I go N-S: since my beds are 'reach the middle from both sides-ish', to get tall plants where they won't shade out low-growers, they need to go at the S end of a N-S bed.
BTW, that info is particular to my Southern hemisphere, temperate situation.

Leila Rich wrote:N-S.
...to get tall plants where they won't shade out low-growers, they need to go at the S end of a N-S bed.
BTW, that info is particular to my Southern hemisphere, temperate situation.

Thanks for the translation. I had to go with E-W orientation due to existing conditions and now I'm thinking that the taller plants (toward the north side of the bed, here in the states) will make it hard to reach in from that side. Also, they are raised HK so I have created small south and north-facing slopes due to the E-W orientation. I'm not too concerned overall, but I agree that E-W is probably better if it works for your air flow and drainage regime.

My land is flat. I have no contours to follow. Using E-W, tall plants can be used to produce shade when planted on the south side of a bed. On the North side of a bed the shade lands in the pathways. This only matters in during winter in the morning/evening. The rest of the time the sun is directly overhead.

In NY I followed the contour. In town down here, I had some E-W, some N-S. Out here in the woods I'm going E-W except near the fence where the fence is N-S. The plants don't seem to mind as long as they get water.

Replies so far have noted several factors to consider. As always it begins with your local situation. In my situation--semi-arid, high elevation--I'm not so concerned about maximizing sunlight. Light is intense here and there are few cloudy days. Moisture is at a premium though, so I orient my beds across contours to slow the flow of water down the slope. Elliot Coleman also indicates that a slope of a few degrees to the south will capture more solar rays and raise temp.s a couple of degrees. My observations seem to confirm that and since I'm looking to extend my 100 day growing season significantly, I try to build beds so that the top surface has a southward slope. Fortunately the larger scale slope allows me to orient beds generally E-W to easily allow for a southward sloping bed tops. In my annual market garden I do grow taller stuff on the N half of E-W oriented beds and shorter stuff on the S half. I don't mind the taller stuff shading the paths between my beds at mid-day. In fact I like to take it a step further and mulch my paths with lots of wood chips to maximise the absorption of water and minimize evaporation.

In my winter beds--under a hoophouse or low tunnel--I grow greens randomly, broadcasting a mix of seed. The plants seem to naturally grow in clumps. The air temperature at ground level within those clumps is higher than in the more barren areas (it's all mulched fairly heavily) in between them. Even in this relatively moderate winter, we've had single digit lows regularly. These greens wouldn't have survived the temperatures without several layers of agribon--enough to reduce the block 50-80% of the sunlight according to the manufacturer's ratings--and one of plastic. Early on I removed the agribon regularly on sunny days in order to maximise the sunlight. More recently I've found that the plants did just as well being covered all the time. I've concluded that their growth is going to be slow regardless and that temperature is more of a limiting factor than sunlight.

I have some further reservations about orienting plantings/bed in order to maximise sunlight, at least outside of areas where sunlight, rather than moisture or warmth is at a premium. The amount of solar radiation striking the earth over the course of a day follows a bell curve, with the maximum intensity in the middle of the day and the proportion of energy building up and tailing off sharply. If I was more concerned about maximizing sunlight, I'd want to find out more about how much plants depend on the intense mid-day sun versus perhaps how little they can get from the relatively weak morning and evening sun. Perhaps it only makes sense to maximise for mid-day sun as working to get more early and late day sun can't really net you much more solar radiation? Another dimension to my reservations is that forests and grasslands everywhere seem to get enough sunlight without worrying about bed orientation. And for all its faults, conventional ag--both pre and post industrialization--seems to have enough sunlight to grow crops without growing in raised beds oriented in any particular direction.