This is the second in a multi-part series on how I developed a comprehensive planting calendar. Read part one here.
How many beds?In my
last post in this series, I outlined how I picked my varieties and why I eventually realized that I needed a planting calendar. The next step was to organize all the various pieces of information for inclusion in the calendar.
Dan Bravin suggested that I use a simple spreadsheet (I chose Google Docs) and run the beds down the side (rows) and weeks along the top (columns). But in order to do that, I first had to do two things: Determine the number of beds I had, and determine the number of weeks I wanted to garden.
To determine the number of beds, I first had to prepare the beds, at least roughly. For sure that involved working the soil, but it also required that I pick a bed width. 24 inches? 30 inches? 32, 36, or 42, 48 inches? All of these are good choices depending on who you ask and what books you consult.

There is really no wrong answer, at least not until you try one width for a year and determine that you'd rather try another width. There are a few considerations though: the size of your equipment, the size of your body, the way you harvest and plant, row and plant spacing for specific crops, and the layout of the plot.
I had to take into consideration the fact that Dan's tiller (which I'll be using this year) has an 18-20 inch wide path. So multiples of 18-20 inches would be easier to till. That narrowed it down to one or two tiller passes. 18 inches is a pretty standard width for home-gardener tillers, but there are models for walk-behind tillers up to 36 inches.

As for body size, I'm about 6 feet tall. In the past, I've done 48 inch raised beds, but I can just barely straddle that far. Being able to hop over a row is very handy, but more important than cross-row traveling is the way you stand when hoeing and harvesting.
Anything wider than about 36 inches makes for hard hoeing because it's difficult to reach the middle of the bed while maintaining an upright posture. And when it comes harvest time, it's darn near impossible to collect zucchini that are hiding under vines and leaves in the very middle of a 48 inch-wide bed, which means you have to harvest from
both sides of a bed, which takes a lot longer.
Two foot beds are really the easiest on your body, but given the same area as another garden using four foot beds, you lose almost 20 percent of your growing area. That's too high a price to pay for ease of growing on sub-acre plots.
Each crop needs different spacing than other crops. Cabbage and squash take up a lot of room whereas radishes take up very little. For those two crops, bed widths don't matter very much since you're going to make a single row of cabbages per bed whether you have 24 inch beds or 48 inch beds. But for crops like carrots, spring greens and tomatoes, you can be forced into particular row spacings by how big your beds are. For instance, with 48 inch wide beds, I can fit two indeterminate tomatoes in a single row. With less, I can only fit one row of tomatoes per bed. Likewise with spring greens: Mustards can get three tight rows on a 36 inch bed, but only two on a 24 inch bed.

The last thing to take into consideration is the layout of your plot. I was thankfully blessed with a single big rectangle of more-or-less identical dirt, with more-or-less the same amount of sun, so I didn't have to plan to grow greens in a shady spot while saving my full-sun beds for peppers and tomatoes. I do have to worry about that in my home garden though. For instance, I have one long bed along a fenceline that grows nothing but greens.
After all these considerations were taken into account, along with measurements for a few perimeter paths and 12 inch inter-row paths, I came up with 24 beds, each approximately 18 feet long, and 36 inches wide. I started my spreadsheet by putting 24 rows down the side, and numbering my beds in order.