In the past I’ve noticed occasional sunscald on my tomatoes. I don’t have a good picture of this right now, but you can see the parts of the fruit exposed to the sun get a little discolored, but usually not so badly it can’t be cut off before eating.
This year was really something else! The fruit of most tomatoes grown in a very sunny spot got sun scald, and I also noticed it on the leaves of my plants. I guess in past years I’ve seen it on my plants too, but I didn’t really realize what it was, and it was never too serious. This year sunscald has been killing some of my tomatoes.
The picture above you can see a particularly bad case, with the leaves turning a purplish color with exposed veins, and the leaves dying on the edges.
Plants in partial shade are less affected, but of course are maturing more slowly with less light.
Is this just a result of our deteriorating ozone layer? Was this particularly bad over northern Europe this year? Did anyone else notice this?
What about solutions? I remember seeing Mike on PlanBe blog in SA mention he has this problem as uses 10% shade cloth. I don’t particularly know where to buy this, or have any experiences with it. Does anyone have an opinion on this?
I asked Lieven, in Belgium, if he had noticed anything this year. He said his greenhouse glass is partly opaqued, and therfore the light is dispersed so he never has this problem. Does anyone have any experiences with this in a greenhouse?
In the meantime, with blight outbreaks in the eastern US, as well as neighboring countries here, there’s no sign of blight on my plants… I hope some of them survive to get blight!
I should add the sun seemed brighter than usual this year, and I had to limit time in the garden because of it’s strength.
I’ve never seen toms like this, but when I grew cacti, years ago in cornwall, I had to shade the glass or they all turned deep purple in summer!
Patrick – I’m growing tomatoes for the first time in 10 or so years so I’m not putting myself forward as any sort of expert here.
However having grown tomatoes successfully in the Adelaide summer with 40 degree days and no ozone layer to speak of, I don’t think climate would be the issue.
Tomatoes are susceptible to stress – could they have dried out a bit on one of your hot days which left them weakened?
James
Drying out is certainly possible. I do have occasional blossom end rot. They are in pots on my roof, and this year I am watering them by hand. I don’t think this explains everything however.
This is definitely sun related. We have the tomato plants on our roof, which has a sunny side and a shaded side. Our tomato plants start in full sun, then progressively move into the shade. The plants in full sun are nearly dead, while the other plants further back are untouched.
The shadow my neighbor’s house casts on my roof is also a distinctive shape, and I can see this shape in the relative health of my plants.
At first I thought it was some disease, and I was picking off parts of the plants to try to control the spread, but then became puzzled because it was spreading in a geometric shape…
On my plot I can also see something similar. Tomatoes in full sun are not doing well, but those growing next to other plants are fine.
Hi Patrick,
In my experience growing tomatoes in a hot climate, some varieties definitely seem to experience sunburn while others don’t. I’m not at all sure why some can take it while others can’t, but from my unscientific observation, that seems to be the case.
I’ve never seen sunscald on my plants except those that I hardened off too quickly and it was mild though I’ve heard of it. Interesting to see a picture. This year, we certainly have not had the full on sun that would be required.