Sunburn strikes again

If you live in a hot climate (like we do) sunburn is an inevitable part of fruit growing, but it can also happen in temperate fruit growing areas during heat waves, which unfortunately are becoming more common due to climate change.

There are three types of sunburn damage you may see:

1. Sunburn necrosis

sunburn-necrosis

2. Sunburn browning

sunburn-spots

3. Photo-oxidative sunburn

sunburn-cooked

This week Ant (who leases our orchard) had his first experience of sunburn, when the Pizzaz plums were not quite ripe enough to pick last week, then the heatwave hit—a blistering day of 44C!

You can see the spots and shrivelling on the skin – that’s a version of sunburn browning. Most of the plums are still perfectly usable for jam, or cooking, or even for eating, but it definitely downgrades them.

Is it preventable? It can be incredibly difficult in cases like this, where there was probably only a very brief window of a day or two when the plums were ripe enough to pick (with the confidence that they would continue to ripen off the tree) before the heat wave hit.

In a home garden, if you were paying careful attention to both your trees and the weather forecast, it may be possible to harvest the fruit (or at least some of it) in time. In Ant’s situation, where he’s managing the competing needs of 5,000 trees it’s much harder.

If you live in an area that experiences heatwaves there’s a number of other things you can do to prevent sunburn damage, including irrigation practices, pruning practices, and careful monitoring—we list 10 different ways to minimise sunburn in “What’s that spot? Common diseases of deciduous fruit trees” (even though sunburn is not actually a disease, but an environmental impact).

The main thing to do when a heat wave is predicted is to make sure your trees are getting enough water, which may mean watering every day. The best time to water is either overnight or in the morning, to reduce evaporation.

When should you pick your fruit?

Fruit tastes better when allowed to ripen on the tree – don’t you agree? It can be tricky to get the timing of your picking quite right though, because it’s also a good idea not to let it get too ripe.

It’s apricot season at the moment, and they’re a good case in point, because if they’re a bit ripe when you pick them, it’s really easy to damage them.

Ideally when you pick your apricots they’ll come away with the stem, like this…

Or no stem, but a neat little scar where the fruit has pulled off the stem, like this…

One of the risks of letting fruit get too ripe is that you’ll get a picking injury at the stem end, as you can see in the following photo. The fruit has pulled away from the stem when it’s been picked, and made a little tear in the fruit.

Unfortunately this may make the fruit continue to ripen too quickly off the tree as it is likely to soften quickly at the scar site, and it can quickly go mushy.

The injury can also make the fruit vulnerable to brown rot, particularly if you’re growing organically (and we hope you are!).  Brown rot is much more likely to start if the fruit is injured, particularly if you’ve had a rainy season before the fruit was picked (because there’s likely to be more brown rot spores on the fruit).

If your fruit is a bit overripe when you pick, use it as quickly as possible, or get it into the fridge to keep it in good condition. But mainly, try to avoid picking injuries when you harvest!

It can be complicated getting the details right, so we’ve developed Fruit to be Proud Of to help home growers know how to choose the perfect time to pick fruit, learn great technique and proper storage practices to make the most of their precious fruit.

Did you get the thinning right?

As we go about picking in the orchard during the apricot season, we see the end result of the thinning we did a couple of months ago – where it worked, and where it didn’t. Here’s a bunch of apricots that were missed in the thinning, and you can clearly see the outcome.

Out of this bunch of four, two apricots have grown normally, and two are stunted, slightly shrivelled, and not really edible – these are the ones that should have been removed when we were doing the thinning.

When they’re removed, you can see that we’re left with two reasonably sized, delicious looking apricots. But…how much bigger could they have been?

The energy that the tree has put into the two discarded fruit would have been better put into growing just two pieces of fruit in the bunch to a larger size.

This is just one reason why it’s a good idea to do thinning early, hard, and thoroughly! We’re aiming to always maximise the ratio of usable, edible fruit to core/stone that the tree produces.

We’ve also seen quite a few of these broken laterals in the orchard, which is another problem caused by leaving too much fruit on a branch that isn’t big enough to carry the weight.

Having put all our care and attention into growing and pruning the tree, it’s then our responsibility to make sure we don’t leave too much fruit on any one branch or lateral than it can carry, to protect these precious growing areas.

Sorry, tree…