Stick to varieties resistant to soilborne diseases (usually hybrids--look for VF designations) and spray preventatively and regularly with fungicide from day 1 of plant-out. If you want to grow heirlooms which are not resistant to soilborne wilts, then look into grafted plants or learn how to graft seedlings yourself. Amending soil very well with organic matter may help. You can also try replacing your soil. If you aren't growing in raised beds already, then build raised beds and fill with uninfected soil. Or, if you can, grow in containers for a few years to try to starve out the pathogen.

Sounds like Septoria (I get it every year here in North San Diego County) and I would guess that your "wilt" is probably insects rather than disease. Here I have problems with thrips starting about mid-July every year. They'll suck the juices out of your blossoms and leaves, leaving dried out, brown leaves and blossoms that dry and fall off at the "knuckle" without pollinating. The leaves will randomly dry up around the plant, rather than the bottom up or top down pattern that seems to go with most tomato diseases. Shake the blossoms or the plant and you'll see tiny gnat-sized bugs fly out, if you have them. Spray with Spinosad for thrips and remove leaves showing the spotting as soon as they appear and you should be able to keep ahead of it. Leave it be and you will eventually end up with dead plants.

I don't worry too much about rotating here, same issue as you with a limited growing space. I just know what I'm going to get and when I'm going to get it and deal with it as best I can. Luckily we don't seem to get a lot of the really killer ground-borne tomato diseases here...at least not that I see or hear about. Insects and insect-borne diseases on the other hand, grrrrrr. I also don't bother with fungicide and haven't had an issue...we don't get the rains and humid weather that seems to bring that on during the growing season. YMMV.

I would think that it would be difficult to eradicate soil borne pathogens. The best bet, as gorbelly mentioned, would be to plant varieties that have resistance to those pathogens : like Celebrity, Better Boy, Big Beef and such. Big Beef, Celebrity, Better Boy often are used as root stuck. But as hybrid they are some of the better varieties themselves. Another option is to try to do your own grafting. This way you can graft heirloom to the above. The technique is simple .

of course container planting is another option but it would be costly. For example a 10 gallon container can cost as much as 20 bucks ( soil + container ) JMO.

Sey

I was just reading an article about biofumigating...sounds promising, but I haven't tried it. Basically, you seed a cover crop, like a potent mustard, then chop or mow it and till it in...when the chemicals in the mustard react with water they make a chemical that either kills or drives out soil born disease and "some" pests, nematodes, maybe some others...might be worth a shot.

Don,

I had 50 plants last year and most of them got fusarium wilt. In mid July on. Over the next off season, I threw a lot of very composted horse compost to it. I was trying to dilute the bad pathogens with new, fresh soil. I deep tilled this compost in. And then I bought about $200 worth of Actinivate, which is a naturally occurring bacteria that binds itself to the roots of plants. I drenched my garden soil with a pump from a rain barrel with the recommended rate. I also drenched the seedlings and plants twice while in their 6 inch pots. I kept them on the healthy side as far as food goes, my Ph was close to nuetral, and they were drip lioned irrigated. Long story short... I did not have any Wilts of any kind this year. And my season is just about over. A lot of people will say that the only thing you can do to treat Fusarium is to commercially fumigate, or to solarize the entire garden for the growing season and pasteurize the soil. But, you kill the good stuff in the soil too. Or to stop growing tomatos for about 5 years.

I will be using it again next season, when growing on. My tomato plants seemed much more vigourous and the roots were filling out a six inch pot in a very short time.

Here is more about Actinovate:

Actinovate SP is a high concentration of a patented biennial bacterium on a 100% water soluble powder. This powerful new product effectively suppresses/controls a wide range of soil borne diseases including Pythium, Phytophthora, Fusarium, Rhizoctonia, Verticillium and other root decay fungi. Actinovate SP is also labeled as a spray application for foliar diseases (when applied as a spray) such as Powdery and Downey Mildew, Botrytis, Alternaria and others. In fact, when used as a preventative, researchers have seen Actinovate SP work as well or better than most chemicals. The benefits of Actinovate SP don't stop there: Because of the special properties of the Actinovate microbe, plants treated with Actinovate SP will be vigorous, have increased vitality and have much better root growth. Actinovate SP contains the microorganism Streptomyces lydicus strain WYEC 108. When introduced into the soil this microbe colonizes and grows around the root system of plants. While settling in the root's rhizosphere, the microbe forms a relationship, feeding off of the plant's waste materials while secreting beneficial and protective by-products. This combination of the colonization and the protective secretions forms a defensive barrier around the root system of the plant which in turn suppresses and controls soil pathogens. S. lydicus also has been shown to prey on certain pathogens, disrupting their cell walls and disabling them in the process. Finally, the by-products of the Actinovate microorganism also aid plants in complexing minerals and micronutrients found in the soil, allowing easier uptake and, thus, creating a stronger, more robust plant. This symbiotic relationship between the plant and the microbe is the optimum balance for a natural, productive soil environment. Actinovate SP makes it happen.

"I'm guessing I have a mixture of fusarium or some soil wilt, and perhaps some other airborn fungal spor, either a powder mildew or something like that."

The first step before doing anything is to determine what the disease issue actually is. Then you seek out treatments and preventatives specific to that disease. There is no "one-thing-cures-all.

Air borne fungal diseases are an annual part of gardening for all of us to one degree or another and there are no soil treatments that have much impact on them. Soil borne and the viral diseases are a totally different matter.

Dave