This has been a challenging year here in the North, which may be part of the problem. It's hard to speculate beyond that, Gmom, without more specifics as to what went wrong. Could you provide more info?

In a small home garden rotation isn't going to make a big effect. For large farmers, it makes a big difference. You're going to get lots of conflicting advice, but the best plan is to know what plants deplete the soil ie "heavy feeders" ( = corn, tomatoes) and which ones enhance the soil ie "nitrogen fixers" (= all legumes). Also some plants share pests so its good not to follow those plants in the same bed the next year (example: don't plant potatoes where you had tomatoes last year).

The problem with crop rotation advice is in a small garden its always going to be close enough for the pests to re-emerge and find their host plants easily. The advantage is that in a small garden it is easy to "recharge" spent soil by using cover crops, compost, and soil building additives.

Here is a link that might be useful: a crop rotation guide

As granite said, for most home gardeners, rotation in the usual sense of the word isn't possible or even useful. There are many prior discussions here about this issue and most seem to agree that when you are stuck using the same garden space over and over each year - as most of us are - then annual soil re-improvement with lots of good compost and other nutrient sources is vital and usually eliminates any problems.

I have been growing in the same garden beds for many years with few problems but it is the heavy use of compost and tilled in cover crops that makes it work for me.

Weather you can't control, your soil quality you can control.

Dave

Just a note to ditto comments from granite and digdirt. I have not found that crop rotation has helped very much in my 2200 sq ft backyard garden; it's just not practicable. While I try do rotate veges as best I can each year, I'm finding that some actually seem to prefer the same location year after year. I've decided that planting a fall/winter crop between each spring/summer crop is going to be my version of "crop rotation".

Rotation can be very critical. For example, in Colorado's Uncompahgre valley, if your onions get pink root and you re-plant them in the same location within 2-3 years, you'll get it again. The organism that causes it can survive dormant in the soil for years. That is just one example, there are many others. I strongly urge everyone to divide up whatever space they have and leave a portion of it idle (preferably with a cover crop) at all times. I split mine into thirds. One third is planted to oats and left for at least one full year.
Oats work well here because they are cheap, establish readily, they mop up unused nitrogen from the previous growing season and they make a dense cover choking out cool season weeds in the fall. Oh and one other thing about oats in this soil, the soil is very mellow and easily worked when it comes back into vegetable production.
I'd much rather have everything planted to vegetables all of the time but, in my opinion, that is not good soil stewardship.

Even gardens need a vacation.