I would suggest rotating tomato crops to other areas, as this minimises the risk of blight being contracted, i have seen varied views that blight can remain in the soil from 2-3 up to 6 years, this would also be the same for potato`s as they are often attacked by the blight contracted by tomato`s. i normally rotate on a 4/5 year cycle, starting with toms then a root veg (beetroot or carrots), then onions & leaks and then either salad or brassicas, and finally restart the cycle again (making sure to replenish as much nutrients as possible after each successfull crop.)
Glyn Hodges wrote (see)
Having lost all of my outdoor tomato plants this year through "Blight" should the ground be treated before trying again next year, and, if so, what with and when? Help appreciated. Thanks.
Glyn, common tomato fungal problems - Early Blight, Septoria Leaf Spot, etc - aren't soil-related. The spores travel in the air. Some of the spores will fall from the leaves to the soil during the season, but, as I posted above, you can turn over the soil and bury them. Any of the same fungal problems that turn up next year will arrive through the air.
The blight that attacks both toms and potatoes is Late Blight. Late Blight spores, unusually, don't live on in the soil on their own. They only remain an ongoing problem if infected toms - or potatoes - are left lying around.
There is, though, as Phil says, an argument for not planting in the same ground in successive years. There are some diseases - mainly viral - that can live on in the soil.
please can any body tell me why my little cherry toms are splitting at the bottom am i doing any thing wrong not all of them are doing it
Some varieties, particularly cherries, are prone to splitting. They have very thin skins. Sungold F1 is a famous example. Beyond that, splitting is usually related to excess moisture. It will often happen after sudden heavy rain. In simple terms, the sudden excess of moisture causes a growth spurt in the tomato but its skin is unprepared for it. Something has to give, and it's the skin. It's like putting on a tight pair of jeans, breathing out, and popping the top button. I speak from experience.
Simple overwatering can also cause it.