In general, we are still seeing reasonably strong crops that are in balance. Weekdays of close to 20°C are not uncommon for cherry tomatoes.

Almost all growers now have fruit setting on the last remaining side shoots. As a result, fruit setting figures are rising significantly. For cherry tomatoes, weekly production of well over 120 fruits per m² is not uncommon. For plum tomatoes (e.g., Romidoro), it is around 35 pieces per m² per week. That promises very high yields in 6 to 8 weeks!

Consequently, the total plant load has already approached the maximum permissible, often well above 650 pieces per m² for cherry tomatoes. Be alert to this: this is truly a very high plant load for early April.

Almost all growers with cherry tomatoes are now harvesting, with fruit weights ranging from just under 11 to just over 13.5 grams, depending on the variety. Generally, this is slightly lower than in previous years. The quality is undeniably good. For the cherry tomatoes, we observe growth periods of 45-48 days, which is slightly slower than last year.

In the later plantings, we see crops that are clearly under-loaded in relation to the available light. In crops that are not sufficiently generatively managed, we see somewhat too many flowers open (more than 3 flowers).

Current situation of our varieties (non-lit cultivation)

Prodelle and Duelle 
We are seeing crops of Prodelle and Duelle that are strongly generative, with 80% to over 95% split trusses on the main stem now. All growers have started harvesting, with generally slightly lower average fruit weights compared to last year.

Prodelle and Duelle will easily continue to produce high percentages of split trusses, even on slightly less vigorous plants. This is also one of the reasons why these varieties tend to "shoot" more easily in terms of plant load. We therefore advise removing any 3- and 4-branch plants, especially given the current plant loads, which are already very high.

Prodelle and Duelle normally set fruit very quickly; generally, it will not be necessary to remove secondary flowering until the summer. However, from now on, keep a close eye on the balance between vegetative and generative growth. Even with the same number of fruits per m², Prodelle and Duelle will still have a higher plant load than, for example, Sweetelle, because the fruit weight is higher. When it becomes visible that the leaf volume (leaf length) is declining sharply, you can stop removing a leaf from the top.

Irrigation: during warm weather with high evaporation (≥ 5.5 to 6 liters/m²), add sufficient calcium to the drip irrigation water and avoid sudden shocks to crop evaporation. Especially with the current low outdoor humidity, suddenly ventilating during the early night can also cause a (too) large shock to evaporation.

Bonelle and Sweetelle
Our new ToBRFV-resistant variety “Bonelle” (TIAM24-5016) and Sweetelle generally show strong generative tendencies. We observe that the percentage of split trusses varies from 60 to 80%, depending on the vigour of the crop.

Furthermore, Bonelle stands out for its very rapid truss formation and fruit setting. Bonelle has already produced about 1.5 to 2 trusses more than Sweetelle. Moreover, Bonelle possesses considerable vigour; for optimal plant balance, quality, and production, we recommend a slightly lower head density than, for example, with Sweetelle.

Trunk treatment: the secondary bloom can be removed from the 3rd/4th truss below the flowering cluster. We recommend removing at least the secondary bloomers, possibly slightly more depending on the plant load. Removing secondary bloom will not incur production costs and ultimately saves on labor costs. From approximately week 14-15 (so now), the taking of a top leaf can be stopped, depending on the crop stand.

Adorelle
We know the ToBRFV-resistant Adorelle as a variety that easily produces (even) more crop due to increasing light. This variety is usually planted at a final spacing approximately 10% lower than more generative varieties such as Sweetelle and Prodelle.

At the moment, we are also seeing quite a bit of extra side shoot growth in Adorelle; this is also a sign of strong growth. Maintain the balance in the crop by retaining a leaf from the top of each truss. An extra leaf can also be removed from the lower part of the crop and "in the belly" if necessary. In the case of an overly vegetative crop, significantly extending the day can be a good steering mechanism to encourage the crop to be more generative. However, keep an eye on the moisture deficit. This can be followed by a short but sufficiently low night (approx. 12-13°C), which is essential for this variety.

At the moment, we are seeing a very high percentage of split trusses (80 to 95%) that are occasionally slightly shorter. In early sowings, the secondary bloom has been removed from trusses 1-3. Important: further truss pruning is absolutely inadvisable; Adorelle will never overload itself.

Our other colors of cherry tomatoes: Tatoo, Baldomero, and Ivorelle
Tatoo and Baldomero are our new ToBRFV-resistant orange cherry tomatoes. Extensive experience with these was already gained in commercial cultivation last year. Like Bamano before, these varieties produce many split trusses. Here too, we recommend pruning the 3- and 4-stem varieties to regulate the plant load. These varieties set very quickly and tend to overload themselves somewhat. In the coming period, try not to aim for too much above 650-700 fruits per m². From now on, also focus more on (vegetative) growth; taking a leaf from the top will no longer be necessary from around early to mid-April. Excessively large DIFs are inadvisable given the current higher plant loads. Incidentally, Tatoo is slightly more vigourous than Baldomero.

Ivorelle is a variety with a strong vegetative tendency. As with Adorelle, we recommend removing a leaf from the top year-round and not pruning.

For these varieties, we recommend using sulfur vaporizers preventively (if permitted) to suppress mildew infestation. If sulfur is already being sprayed against gall mites, this will not be necessary.

Romidoro and Romindo
With our new ToBRFV-resistant plum tomato varieties Romidoro (TIAM23-4633) and Romanto (TIAM23-4621), we have a great addition to our assortment.

Romidoro is a generatively strong variety – comparable to Romindo – with remarkably high truss formation. The first trusses are usually pruned to 5 or 6 (in early plantings). Important: Romidoro produces flowers easily throughout the year, which set readily. We recommend pruning away the last one or two flowers to ensure the most uniform fruit size possible and optimal production. For summer spacing, we recommend 3.75 to slightly more than 4 heads per m², depending on the greenhouse type and desired fruit weight. With Romidoro, it is now worth considering removing no leaves from the top.

Romanto is a slightly more vigourous variety with larger fruits. This variety is also very suitable for truss harvesting. For Romanto, initially remove one leaf from the top and ensure sufficient generative growth. For this variety as well, we recommend pruning away the last one or two flowers per truss to ensure the most uniform fruit size possible and optimal production. Romanto has a slightly longer truss stalk; we advise continuing with pruning or scraping slightly longer than usual to ensure good fruit development. For Romanto, we recommend a slightly lower final spacing: about 3.5 to a maximum of 3.75 heads per m².

Potassium and calcium: Both varieties have a somewhat higher potassium requirement at the start. Therefore, keep a close eye on the potassium level and adjust upwards in a timely manner. Later in the cultivation (when evaporation exceeds ± 5 liters/m²/day), it is important to aim for a higher calcium application and slightly reduce the potassium application. Additionally, be cautious with the use of ammonium nitrate to control the pH. We will return to this in the upcoming cultivation information. 

Macrolophus seems to develop easily on Romindo. Ensure that the Macrolophus population does not become too high (above approx. 8-12 individuals per plant).
 
Regrowth, RTR, and maintaining balance
After the first harvest, regrowth usually follows quickly. To maintain a good balance in the crop, it is important to actively “manage with the light,” also known as RTR (Ratio between Temperature and Radiation). Therefore, on days with high irradiance, the daily temperature must be kept sufficiently high. Depending on the actual daytime temperature, we must adjust the nighttime temperature to aim for the desired daily temperature. Keep daily temperatures between 17°C (600J, dark weather) and 20-21°C during sunny weather (2000J and above) for the coming months. If there are several days of insufficient light, the daily temperature can even be aimed for temperatures below 17°C.

During cool and sunny weather (like the current weather), ensure that the temperature is up to standard in the morning. Introduce ventilation in time (possibly on both sides), but be careful not to ventilate too quickly. Do not allow the greenhouse temperature to rise too high late in the afternoon for crops that are in balance (max 25-26°C). If solar radiation decreases slightly in the afternoon, the temperature can be maintained.

For crops that are not yet sufficiently generative, a pre-night period can still be a good control measure; in cherry tomatoes, this results in the necessary split trusses and ensures a higher fruit weight. Ventilating into the pre-night period provides additional dehumidification; however, be careful with this when outdoor humidity is low. In the case of (too) strong growth, for example in an under-loaded crop, it is advisable to extend the daytime temperature until sunset or even beyond.

Screen usage, moisture, and minimum pipe
Currently, the crops are already producing too much moisture to close the screen during the day. If necessary, use a screen only in the (very late) afternoon and at night, and always monitor the moisture levels. Do not let the moisture deficit drop below 1.0 g to keep the crop healthy. A moisture vent can be used if necessary.

If it becomes more humid, ventilation can be provided above the screen, and as a next step, set a minimum pipe temperature of 30-35 °C to remove the moisture.

Furthermore, be critical of the use of the minimum pipe if there is already sufficient activity.

Watering strategy  
Aim for a mat EC of approximately 4-4.5 mS, with a drainage percentage of 25-30%. Ensure sufficient nutrient supply with low evaporation: the drip EC should not drop too low during somewhat colder weather with high solar radiation, between 3.0 and 3.2. In warmer weather, dripping can be done at a somewhat lower level, but preferably not below 2.8 mS. This does not benefit the taste.

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

Watering can be stopped approximately 2.5 – 3 hours before sunset. If the plants are still evaporating too much after the last drip (> ~7% depletion before 10:00 PM), night watering can be performed. We recommend a minimum intake rate of 10-12% during the night.

Fertilisation
Due to the current high and still increasing plant loads, potassium requirements will be high; ensure that these remain at a good level for good colouration. Pay particular attention to Prodelle, Duelle, Romidoro, and Romanto to ensure that calcium levels remain in a good ratio to potassium levels.

Furthermore, ensure a proper balance of nutrients; therefore, do not "play" with nitrogen application for now. Provide sufficient fertiliser to maintain adequate growth.

What are the other points of attention for the next 6 to 8 weeks?

Plant load and plant balance
As previously indicated, plant loads have increased very rapidly in recent weeks. The growth duration will not immediately decrease with cooler weather, meaning plant loads can become so high that the plant may become overloaded. For cherry tomatoes, ensure that the total plant load does not rise too high (> 650-700/m²)! Maintain speed and growth in the crop where necessary and, if necessary, remove extra points—such as secondary flowering—up to the third truss below the flowering truss.

Pay attention to a good plant balance, especially for Sweetelle, Prodelle, Duelle, Baldomero, Tatoo, and Bamano. In general, the removal of top leaves can soon be stopped, and a slightly stronger focus can be placed on growth. For these varieties, a high DIF is no longer necessary when aiming for more; this only increases the plant load.

Bumblebees: Cluster formation and flowering rates are very high at the moment; do not let this catch you off guard and ensure a sufficient number of bumblebees to allow pollination to proceed optimally!

Diseases and pests: In general, no major problems have been reported (yet).

Fungi: In illuminated crops, there is somewhat more botrytis visible, mostly having entered through the leaf margins.

Many farms are anticipating a Tuta infestation with pheromone confusion.

Furthermore, it is always important to scout thoroughly, for example by keeping a close eye on the sticky traps! Whitefly pressure will increase; anticipate this quickly by releasing extra parasitic wasps and possibly hanging extra sticky traps in the heads.

The next crop info will appear at the end of May.