Garden soil is one of the top five most important factors in tomato garden success. I've also noticed it's the first thing gardeners blame when things go wrong, especially in the absence of an obvious culprit.
You will have to fill your raised beds with soil from somewhere and it can be very tempting to just order it from a soil products company that will dump it next to your garden. However, you may have perfectly good soil on your property already. And soil already present in it's native environment is more likely to have a balance of elements. I learned this the hard way.
It is likely that if I would have evaluated my native soil in the first place, I could have amended it to fit the requirements of my tomato sauce garden, saved a lot of time and money, and grown more tomato sauce in less time.
If you have soil that you can dig up and put into your beds--check to see how quickly it drains, whether or not it supports worms, and how well other plants (even if they are weeds) are growing in it. You can also have it professionally tested.
The best way to find out what is and is not in your soil, is to have it tested. There are several testing options depending on the information you wish to obtain.
As it turns out, garden soil can be improved without expending too much time, effort and money. We now enjoy the best harvests with the least amount of work and you can too.
Start by composting all winter right in your tomato beds. This technique will prevent your soil from becoming compacted in the rain and snow.
Brew your own compost tea. You can spray this solution all over your plants, the soil, and your lawn. This way, the good microbes will outcompete the bad microbes both on the plants and in the soil.
If it is necessary for you to import soil for your beds, research the options in your area and try to find a product that comes with a soil analysis so you'll know what you are getting. It will likely be more expensive than a basic garden soil in the short term, but much more cost effective in the long run. You want to be sure the soil contains balanced nutrients and minerals and a healthy microbiology with plenty of composted organic matter.
The book: Teaming with Microbes: A Gardener's Guide to the Soil Food Web by Jeff Lowenfels and Wayne Lewis includes tests you can do yourself to evaluate the quality of your soil.
From this book, I found out that encouraging worms and microbes brings nutrients to the soil that are ready for the plants to incorporate. I also learned that a healthy balance of microbes in the soil discourages pests that can damage plants.
For more information on the concept of Nutrient Dense Gardening, check out the book, The Intelligent Gardener, by Steve Solomon with Erica Reinheimer. Incorporating the concepts in this book has changed my gardening methods and dramatically improved my results.