Daylight savings is over as Autumn really begins

Fruit load versus light

Autumn has finally arrived!  The summer has officially ended. There have been warm nights this week in the greater Auckland area and now there is a cold snap on the way!!  The South Island is starting to get some snow.    I have noticed a lot of hay and silage being harvested in my local area, in the past week, which indicates even though it has officially been our warmest summer on record there has also been a lot of rain fall. 

The days are shortening so reducing crop load needs consideration.  Tomato crops, being grown through the winter, should have their fruit load m2 reduced.  The weather and light levels are still reasonable so there is temptation to set too many fruit per truss.   Trusses currently being set will be picked close to the shortest day.  If you don’t reduce fruit numbers and prepare for the lower light periods now, then your plant will potentially need to be slowed unnecessarily in two months’ time. The flowers/fruit set in June and July, historically, is where most financial gains are made.  You need to keep the setting speed as optimum as possible in late June and July but you will struggle if you are carrying too much fruit load.  An extra .1kg/m2 per week, in August and September, will mean much more to your bottom line.  Another benefit of a reduced fruit load, during June and July, will prevent stress on your plants, which in turn will mean they are stronger to fight off infection. 

It is always hard to make the call when to drop or increase fruit load. Over 20 years of growing it never got any easier to make that decision, you just have to trust the numbers and look at the fruit load vs. light.  It is really important to think about the current flowering truss and the predicted light levels you will have when you pick that truss. 

Cucumber growers still have enough good light to sustain high fruit loads, but this will change and growers need to react to the weather pattern week by week.  Try to avoid fruit abortion. If this happens, it is either a physical problem or you have overloaded your plant in relation to falling light.

Reducing your irrigation is another key factor.  Start reducing the water content to maintain root health.   Stop times should be adjusted accordingly.  I can not give generic water content recommendations as there is so many different types of substrates and different volumes used.  As a generalisation a 5-10% reduction in water content, compared to summer, could be a good starting point.   If you do wish for more specific detail tailored for your crop then please contact me for more options.

It is also time to get those heating systems serviced!  Especially if you have had them turned off for a while.  There is nothing worse than finding out the heating system has an issue when the weather starts getting cold (this week!!).

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Article Written by Stefan Vogrincic, Consultant Grower2Grower