What has the climate been like so far and how have the plants responded to it?
Exceptionally sunny spring and ideal growing conditions
We have had an exceptionally bright spring. The cumulative light sum from week 49 to week 19 is around 31,000 J/CM2 more than in 2024 and around 22,000 J/CM2 than the multi-year average. This has of course had an impact on productions so far: productions are higher than last year across all segments.
With the current sunny and relatively warm weather of the last few weeks, we are seeing the growth period decrease considerably, often well below 40 days for e.g. Prodelle and Sweetelle. Productions are very high with productions well above 1 kg per m2 for several weeks
Light sums in the West of the Netherlands, up to and including week 19
Impact on crop status / plant load
We still see a high plant load at almost all growers, although usually lower than a few weeks ago. Weekly production of more than 120 pieces per m2, with a plant load of more than 700 pieces per m2 are not an exception at many snack tomato growers. Thanks to the exceptionally high amount of light with easily controllable daily temperatures, the high plant loads do not yet cause energy shortages in the crop. The flower quality and setting are good everywhere. At growers who ventilate a bit more easily, we see the leaf length quickly decrease.
At snack tomatoes, we see fruit weights between 10.5 and 12.5 grams, sometimes lower at growers who went to the summer distance (too) early. For optimal cultivation, it is best to increase the plant distance in several steps, anticipating the increasing light sum.
Current situation of our breeds
Prodelle and Duelle
Plant load, fruit weight:
With Prodelle and Duelle we see crops that are strongly generative, with now 80 to more than 95% split bunches on the main stem. Both Prodelle and Duelle will easily continue to give these high percentages of split bunches, even with a slightly less powerful plant. This is also one of the reasons that these varieties "shoot" a bit more easily in plant load. We therefore advise removing any 3 and 4 branches, certainly with the current very high plant loads. With the same plant load in pieces, this will require more energy from the plant than with, for example, Sweetelle, due to the higher fruit weight. Just like with Sweetelle, try not to exceed 650 to 700 fruits per m2, prune if necessary.
Leaves from the head: as indicated earlier, we see that with growers who are already aerating a bit more easily, the leaf length decreases considerably. In that case (certainly) no more leaves need to be removed from the head.
Prodelle and Duelle have a smooth setting in themselves; a high peak in the afternoon is less necessary than with other varieties. In addition, it is important to prevent too large shocks in evaporation in the coming months, so be careful with airing out a possible pre-midnight too suddenly, for example.
Evaporation and watering:
Prodelle and Duelle generally evaporate somewhat more than other varieties, up to 10-15% compared to, for example, Sweetelle and Adorelle. Therefore, keep a close eye on the watering in lean weather. In warm weather with (extra) much evaporation, we recommend offering sufficient calcium. The K/Ca ratio may then be temporarily adjusted considerably.
Adorelle
Adorelle has a plant type that can cope very well with a lot of light and a lean climate. With the current very high light sums, we still see very strong crops with many split bunches (up to 90% two- and three-branch). We advise to steer Adorelle as much as possible generatively in the coming period. In a less generative weather type, work with a good peak temperature in the afternoon and a sufficiently low pre-midnight (12-13°C, if possible) to stimulate bunch strength and setting. The day may easily be around 21°C with a light sum of 2000J/cm2. We now see that the fruit production is just above 100 fruits per m2 per week, continue to steer this. Pruning will not be necessary, Adorelle is a variety that does not overload itself. Also continue to include a top leaf, certainly if the crop still needs some extra generative steering.
Sweetelle
The crops are generally generatively strong. The percentage of split bunches had decreased slightly in mid-April but is now increasing again to 60-80%. We see, just like in previous years, that Sweetelle corrects itself quite easily in terms of bunch size when the plant load increases. As a result, the plant balance is still good despite the relatively high plant load. It is important to maintain sufficient crop volume for the coming period. We advise not to remove any more top leaves from the head for the time being.
Keep steering on plant strength in the coming period! We are now seeing many growers produce fruit of well over 100 pieces per m2 per week. We advise a maximum plant load of 650 - 700 pieces per m2 for Sweetelle in the coming 6-8 weeks, also partly depending on the average fruit weight. A plant load that remains above this for a long time is at the expense of growth and plant balance. Bunch pruning is being used more and more. We advise to prune the tips from the truss 3-4 from above.
Especially with a less active outdoor climate, aim for a sufficiently high peak temperature of 24-26°C between approximately 2 and 4 o'clock in the afternoon. Keep a close eye on the development time of the fruits; if possible, use the growth tube to bring more heat to the fruits. This is also a more energy-efficient way of heating.
Tatoo, Baldomero and Bamano
Baldomero and Tatoo perform very well, with a crop and fruit type comparable to Bamano.
Baldomero, Tatoo and Bamano also produce a lot of split bunches with an easy setting, even with a high plant load, which allows the plant load to increase quickly. This may make it necessary to prune the 3rd and 4th branch, in order to control the plant load and maintain the balance in the crop.
Until at least mid-July, it is not necessary to remove a leaf from the head of these varieties. It is important to ensure sufficient leaf volume in the greenhouse. For stimulating plant strength, see the advice for Sweetelle and Duelle.
Climundo
Our ToBRFV resistant large vine tomato variety Climundo has an average filled crop type and a lot of stamina. The trusses give a very stable number of flowers throughout the season (8-11), with a smooth setting. This also makes the variety extremely suitable for loose harvesting. In the case of an assimilate surplus, a sufficiently high afternoon temperature together with an extension of the day is a good way to control the plant generatively while maintaining an optimal cultivation speed. If necessary, keep the crop sufficiently open by removing a leaf from the head at the truss.
Climundo has a good colouring but needs sufficient potassium for this. So pay close attention to this when watering, but also ensure an active climate so that potassium is more easily absorbed. Climundo is very strong against blossom end rot; an adjustment (increase) of the potassium dose is therefore not immediately a danger for the sensitivity to blossom end rot.
Macrolophus seems to develop easily on Climundo. Make sure that the macrolophus population does not become too high (above approx. 8-12 individuals per plant).
Advice on climate control (temperatures, window positions, humidity, pipes, etc.)
Heating up to the day temperature:
We see that sometimes too little energy is used to heat up the crops to the day temperature, resulting in risks such as crops getting wet at (too) low night temperatures. Sufficient heating up to the day temperature is the best use of energy at this time of year! The minimum tube may be calculated back with increasing radiation with a sufficiently active climate, above 350 W it can then be omitted.
Depending on the realised day temperature, we must enter the night temperature to control for the desired 24-hour period. Try to keep the 24-hour temperature as low as possible with a low light sum.
Ventilation:
At lower outside temperatures, the ventilation temperature can be set close to the heating line with a fairly high P-band, so that ventilation is quick but not too much. At (expected) higher outside temperatures, the P-band can be set a little lower so that ventilation is a little smoother.
In sunny weather we like to see a RH of between 70-80% to maintain growth. If the RH drops below 70%, the windward side can be reduced to a maximum of 10-20%. From 3 to 4 hours before sunrise it can be considered to further limit the window positions to create a more growth-promoting climate. Please note that the above control is only recommended if the greenhouse temperature and crop condition allow it.
CO2:
In recent years we have seen the CO2 gift decrease somewhat due to less CHP use and/or too high costs for other CO2 sources. This will generally result in somewhat (weakly) vegetative crops. In any case, try to bring a minimum amount of CO2 into the greenhouse, for example by steering on at least the outside value in the greenhouse.
Advice and points of attention for the coming 6-8 weeks
LAI and growth power
For most varieties it is important to steer towards a growing and powerful crop, this way we maintain sufficient LAI and speed in development.
Growing crops can better cope with moments of stress. For most varieties the following applies: always grow some ‘surplus’ so that there is sufficient power available to absorb a dark period and to maintain sufficient leaf elongation
Watering strategy
Root quality has been good so far. Any changeable weather conditions will make it more difficult to keep the roots in good condition.
Aim for a volume percentage of reduction in the mat of 8-12% to maintain growth and root quality. In darker weather, reduction can be aimed at 12% or more.
Try to drip between 2 hours after sunrise and 3-4 hours before sunset to achieve the desired reduction. Additional night shifts may be necessary if evaporation is unexpectedly high. The first drain can be achieved approximately 3.5-4.5 hours after sunrise, depending on the weather.
Fertilisation schedule
The nitrogen (nitrate) gift should not be limited at this time of year so that the plant can maintain sufficient growth.
Keep in mind that at a high pH the availability of calcium and phosphate for the plant decreases considerably, which increases the sensitivity to blossom end rot.
Aim for an EC of 4 - 4.5 mS in the slab to maintain sufficient growth. An EC of 3.0 - 3.5 mS can be dripped in, with high radiation you can go back to 2.7-2.8 mS. A drip EC that is too low will negatively affect the taste. Make sure that in weather types with little evaporation and watering sufficient nutrition is offered to prevent pale heads and "soft" crops.
Diseases and pests
The use of inoculation with a weak strain of Pepino seems to be declining somewhat. As a result, we may see more problems with “spontaneous” Pepino infections in and outside the Netherlands.
In general, no major problems with insect infestations have been reported (yet), except for a few companies where nesidiocorus has already been found. These are mostly companies with a lit and unlit crop next to each other.
We see slightly less gall mite than in previous years. Good scouting and preventive sulphur spraying have clearly helped many growers. Spraying sulphur (at the top metre) against gall mite is less harmful to the young Macrolophus population.
General tips for the coming period
The maximum irradiation was already high and will increase considerably in the coming period. Consider a coating in areas with higher irradiation and/or a lean climate (more applicable outside Belgium and the Netherlands)
The next crop update will be available at the beginning of July