Climate and Light Management 
Be mindful of being timely with temperature control in the morning during cool and sunny weather. Ensure to ventilate in time (potentially on both sides), but be cautious with excessive ventilation. In the afternoon, do not let the greenhouse temperature rise too high for crops that are in balance (maximum 25-26 °C). If the sunlight diminishes in the late afternoon, the temperature can be maintained.

For crops that are not yet sufficiently generative, a pre-night can still be a good control method. This results in the necessary split trusses for pruned tomatoes and contributes to higher fruit weight. Ventilating towards the pre-night helps with additional dehumidification, but be cautious with low humidity outside.

After the first harvest, regrowth usually follows promptly. It is important to maintain the balance in the crop. In the case of excessive growth in an underloaded crop, it is advisable to extend the day temperature, for example, until sunset or even beyond.

For a good balance in the crop, it is important to "steer with the light." On days with high radiation, the 24-hour temperature must be kept sufficiently high. Depending on the achieved day temperature, we need to adjust the night temperature to achieve the desired 24-hour temperature. Over the next few months, maintain 24-hour temperatures between 17 °C (600J, dark weather) and 20-21 °C with sunny weather (2000J and more). In case of several days with insufficient light, the 24-hour temperature can even be set below 17°C.

Screen Usage, Humidity, and Minimum Pipe Temperature 
Currently, the crops are producing too much moisture to close the screen during the day. Consider working with a screen only in the (very late) afternoon and at night, always monitoring the humidity. Do not let the humidity deficit drop below 1.0 g to maintain crop health. Consider using a small gap for humidity control.

If the humidity increases, ventilate above the screen and, as the next step, set a minimum pipe temperature of 30-35 °C to remove the moisture.

Be critical of using the minimum pipe when there is already sufficient activity.

Plant Load

As mentioned earlier, plant loads can increase significantly in the coming period. With cooler weather, the duration of growth will not decrease immediately, potentially leading to excessively high plant loads, which can burden the plants. For pruned tomatoes, ensure that the total plant load does not exceed a certain threshold (> 650-700/m2)! If necessary, manage the speed and growth in the crop, and consider removing additional points, such as secondary shoots up to the third truss below the flowering truss.

Plant Balance

Pay attention to maintaining a good plant balance, especially for Sweetelle, Duelle, Baldomero, and Bamano. Generally, it will soon be possible to stop removing a leaf from the top and slightly steer towards more growth. For these varieties, a high DIF is no longer necessary in good weather, as it only increases the plant load.

Irrigation Strategy

Aim for a moderate EC of approximately 4-4.5 mS, with a drainage percentage of 25-30%. Ensure sufficient nutrient supply during low evaporation: the drip EC should not decrease too much with colder weather and high radiation, ideally staying between 3.0 and 3.2. During warmer weather, the drip EC can be slightly lower, but preferably not below 2.8 mS, as this may affect the flavour.

Start and stop times: Ensure that watering begins only when the plant is sufficiently transpiring, approximately 1.5 to 2 hours after sunrise or at 70J/cm2.

Watering can be stopped approximately 2.5 – 3 hours before sunset. If the plants are still transpiring too much after the last watering (> ~7% shrinkage before 22:00), additional night-time watering can be implemented.

We recommend a minimum shrinkage percentage of 10-12% during the night.

Fertilisation Schedule

Due to the current high and still increasing plant loads, the need for potassium will be high, so ensure it remains at an adequate level for good coloration. Particularly for Duelle, ensure that the calcium levels remain in good proportion to the potassium levels.

Any reduced nitrogen applications will need to be restored to normal levels to stimulate growth.

Diseases and Pests

Generally, there are (still) no major problems, aside from viruses, of course.

Many farms are preparing for potential Tuta infestations with pheromone confusion. It is also important to scout carefully, for example, by monitoring the sticky traps closely! Whitefly pressure will increase, so be proactive by introducing additional biological control and potentially hanging extra sticky traps in the heads. It's best to skip Macrolophus rows when pruning leaves to allow the population to further develop.

The next crop update will be available at the end of May.