Light levels rose sharply last week

By Stefan Vogrincic

This week crop reports from both the North and South Island have shown a sharp increase in light levels.

Predicting spring weather will always be near on impossible. However, we are able to rely on the fact the day length will increase no matter what, and if we do receive cloud free days plant growth will change rapidly.

For tomato crops you should be at summer density, regardless of whether you are growing cherry, cocktail or large truss.  Large truss, depending on the crop cycle and location, should be at or nearing harvest from the additional side shoots taken in July/August.

For cocktail trusses, I prefer to take the additional side shoots in two stages, one in late winter and one in September.  If you do not have enough density, when the spring sun shines, you will struggle to add the additional fruits per m2 you require quick enough.  If the weather does not play nicely, you have the option to prune harder on those additional side shoots.   However, if you don’t have the extra shoots already flowering you will be behind the eight-ball at this time of the year.

Cucumbers, for me is all about speed.  Growers may still be pruning – one on and one off, which is prudent with such changeable weather – you have to manipulate the speed of the plant using your temperature settings to maximise this ‘speed’ of growth.  A good example this week on a visit noticing a 2000+ joule day followed up by a cool night.  In the perfect case scenario, I would’ve increased the night time temperature to maximise growth.  Unfortunately, due to high energy prices and poor returns some heating has been turned down to provide minimal heat input.

In this scenario I would not increase fruit numbers because light levels are so unstable, the grower will need to accept they are not getting the ultimate speed of production or potential from that particular scenario.

Key for the next month for tomatoes:

Truss prune to summer density – you can always remove flowers but not add them!

Please – still heat correctly as you do not want vegetative plants or fat stems that will cause you issues in  Autumn.  Ambient night time temperatures are like a yoyo!

For advice contact stefan@grower2grower.co.nz