Vetch is a good cover crop for your tomato patch. It will grow over winter. In spring before the vetch flowers, which will be maybe a month or 2 before it is time to plant your toms, you just till it under as best you can. It then decomposes adding organic material and nutrients to your soil.
There is info on the internet about studies done concerning the beneficial relationship between vetch and tomatoes. Google it.
You could probably also add some soil conditioners and manure to the soil now if your plants are out.
How was your harvest, even though the plants were too close together? Did you get some nice toms? That is how you know if your current soil was good enough.
Cover crops and additives help to renew your soil for next year.

I don't claim to be an expert on this subject, but I'll share what I've read in the book "Gardening in the Rocky Mountains". I'm in the same zone as you (5), so the advice is probably applicable to your garden as well.

1)Begin with a soil test. My local university charges $22 for this service. They will tell you about pH, nutrients, and organic content, and what you should add for optimum balance.

2)(Here I quote:) "Adding organic matter should be an annual process in a new garden. As organic material breaks down and releases nutrients for plant use, it will need replenishing." The author goes on to say that you should add compost, peat moss, manure, etc., in the fall, so that it will mellow over the winter. Work it to a depth of 6 inches, and leave your garden in a rough state. Alternating freeze/thaw cycles will break down the clods, leaving your garden ready to plant in the spring. The author recommends adding 1.5" of organic material to especially bad soil. Your soil sounds pretty good, so you probably don't need this much. I add maybe 1/2" of manure and compost each year, and this seems to work well.

Be sure to also check out the many great discussions on how to improve and maintain your garden soil that can be found over on the Soil forum here.

And every garden benefits from at least an annual dose of more compost. 2x a year is even better. ;)

Dave

Here is a link that might be useful: Soil Forum

Pirate,

I'll be the lone wolf here. If your dirt is normal, run of the mill stuff found in most yards, it doesn't need amended. Yeah, adding compost and fertilizer helps, especially after the first year of use. But except for spreading 18 pounds of fertilizer on 900 sf, I didn't add anything the rest of this year.

I have 18 or more tomato plants in a 30 foot space - are your plants closer than that? And the rows are only about 30" apart, probably closer to 26". But even though a couple of plants are worthless, I've still have managed to harvest 650 pounds and before I'm done I hope to be at about 750 (depending on how long before Jack gets here).

Raising a garden is not rocket science. Sow winter wheat in the fall, till it and plant seedlings a couple weeks later in the spring, water if there is drought, pray temps are moderate.

Mike