WHEN some people complain to me that their tomatoes have developed a black scab on the base, I bluntly tell them it was their fault.
One or two get quite hurt.
When I explain that the real reason for this disorder - called blossom-end rot - is inconsistent and irregular watering, they often hotly deny they are neglecting the tomato plants.
Some insist they water their tomatoes every day, although most of the culprits may admit they are growing them in tubs, raised beds or in sandy soil.
And that's the problem - even with heavy mulching.
Insufficient water always occurs at this time of the year, particularly when drainage is super-perfect as in tubs and raised beds.
What happens is obvious.
The soil around the roots of tomato plants starts to become dry and soon the core of the root systems also become water-repellent, often because the organic matter content is very difficult to get wet again.
So only the outer parts of the roots get watered, especially if a hose is hand-held and the job is done in a rapid, superficial way.
When watering plants like this, it is easy to be tricked because the surface of the soil turns dark and looks very wet.
But down below it can still be almost bone dry because it takes a while for good penetration to occur.
Many frustrated backyard tomato growers search for more information about blossom-end rot.
They will probably discover that these black scabs are an indication of calcium deficiency.
I've even read articles which advocate spreading lime over the soil around tomato plants - despite the fact that they prefer an acidic soil.
Let's be clear here.
Calcium deficiency is extremely rare in plants due to lack of this mineral in garden soils.
We add calcium - as lime or dolomite - to our vegetable gardens, not to supply plants with the stuff, but to make acidic soil more alkaline for so-called lime-lovers such as celery, asparagus, onions, garlic, lettuce, legumes and most brassicas.
So while it is basically true that tomatoes showing blossom-end rot disorder are because of calcium shortage, this deficiency is actually caused by lack of water.
In short, all plants need water to take up calcium and other mineral nutrients but if there is irregular, inconsistent watering of tomatoes blossom-end rot disorder is inevitable.
The solution is a combination of slow, deep-soaking irrigation with a thick mulch, well tucked in around the lower stems of the tomato plants.
And even mulching can be tricky.
If it just keeps soil close to the surface moist, the tomato roots start growing upwards to get at it.
That leaves shallow-rooted plants highly vulnerable to drying out and dramatically collapsing during extra-hot weather.
That's why mulches and deep, deep watering must always go together.
Luckily, the great thing about tomato plants is an ability to recover rapidly after they have started to slump due to lack of water.
When they are thirsty, the tips droop mournfully and yet within an hour of a slow, deep watering they will have picked up and are looking quite perky.
But allowing this to occur too many times means you may get healthy-looking tomato plants, but the fruit develop these awful unsightly scabs at the base.
Just the same, even this avoidable disorder is no big deal.
When I slice tomatoes I always discard the tough layer of skin at the base, and the stalk end too, because they are indigestible anyway.
