Pest & Disease: 4 tips to rescue tomatoes from the problems caused by rain

What a difference in weather to last year’s lead-in to summer…! This time last year, we were battling with the incredibly hot, dry weather and now we have the opposite with heavy rain, snow in some parts and strong winds. The intensity of this rain followed by warm, humid sun can have devastating effects on our tomato plants.

Problem #1

If you planted your tomatoes early and have lots of tomatoes on your plants by now, this heavy rain can cause their skins to crack and split open.

Tip #1

It is best to thoroughly check your tomatoes and remove any split ones, as these can drop onto your garden and attract fruit flies among other pests.

Problem #2

If your tomatoes have flowers at this time of heavy rain, this can cause blossom end rot on your fruit. This is a spot at the end of the blossom where the tomato is formed that has been soaked by the water from the rain. Importantly, this can actually also be caused by overhead watering – so do take care.

Blossom end rot can be indicative of a lack of calcium in the soil and also occurs in capsicums, cucumbers and melons.

Tip #2

As your tomato starts to grow, you will notice a brown patch appearing on the bottom of the fruit. It will increase in size as the tomato grows and cause rot in the fruit. Take care to remove any tomatoes you see this rot on.

However, this is not a disease – just a problem that is caused by either rain or lack of calcium absorption.

Problem #3

Calcium is essential for development in tomatoes. When the soil’s moisture fluctuates from too dry to too wet, this can limit your plant’s ability to absorb this vital mineral – this is why mulching is essential.

Too much nitrogen in the soil can equally prevent absorption; or if the pH is too high or low. Tomatoes like it around pH 6.5.

Tip #3

I find that if you have a good balanced soil with good humus and a good mulch you are generally ok.

To support growth and maintain calcium absorption, it is important to keep a good moisture level in your soil. I tend to only water my tomatoes once or twice a week and water at the root and not overhead.

When I grew up, my dad used to put a clay plant pot in next to each tomato and this was where it got watered. By doing this it took the water down to the roots where they were cool under the soil and prevented evaporation. Usually, I find the old methods are the best.

Problem #4

With all this rain and warmth, your tomatoes will have pumped on the growth and seem to be getting taller by the day! They will need support and control to grow successfully – but take care.

Tip #4

A few things to remember are never tie or remove leaves in the wet. Tie your tomatoes on a dry day with either soft cloth or stretchy string and remove leaves for added airflow on a dry windy day as this will heal the plant quicker.

Happy tomato gardening!

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