The months of April and May were characterized by heat and a lot of moisture. Syngenta: "As a result, the plants have not become very generative as they would do normally with heat and a low moisture content. But the vigor in the plant has been greatly reduced because of the high temperatures. This is mainly expressed in weak trusses. Because of these high temperatures we see fruit set failure with most crops, which in itself does not have to be a disadvantage. This way the growth vigor returns in the plants more quickly."
Day light is reducing, so we have to lower the fruit load to keep the scale well into the autumn. In order to keep the plant vigorous, topping the plant or extra short pruning always is a good consideration. The ideal number of unlighted heads is between 4.2-5 heads/m2. But in general, a higher final distance is maintained for lighted cultivation than for unlighted cultivation, because they have a longer stem in the spring / summer. This could make their growth more complicated, allowing them to burn faster. But this again is compensated with extra stems.
Sweetelle
Sweetelle is generative with a somewhat weaker truss. We now see fewer double trusses due to the decreasing vigor and the higher night temperatures.
Angelle
Angelle has as usual some more growth vigor than Sweetelle, but a shorter truss. Due to the high irradiations the fruit weights are nicely up to standard and the pointed fruits are sufficient.
Funtelle
Funtelle is more vigorous and stronger than Sweetelle, which should result in higher production towards the summer and autumn.
Ivorino
Ivorino starts to get leaves late, so less extra leaves are removed from the plant.
Bamano
Bamano has a nice balance, sufficient crop filling and still a good setting.Climate
Especially when crops are too generative, high day temperatures should not be used. If possible, keep the temperatures around 23-24 °C on sunny days. This is how we try to create more growth vigor. If the RH goes below 70%, the wind side must be tightened to a maximum just below the ridge. Because of this action the temperatures will rise in the greenhouse. If the temperature stays below 27-28 °C, the wind side can be tightened more. If the irradiation after a beautiful day drops below 300W, we must close the windows to get the RH back to 75-80% as soon as possible. This is done so that the generative crops can restore their water balance. On dark days it is wise to grow cool, 20 °C is warm enough. Airing should be done to remove the moisture out of the greenhouse and to reduce it for a couple of days. On both sunny and dark days it is important to keep the nights as cool as possible in order to reduce the full days and to take on the cold. Minimum pipe temperature is now no longer necessary anymore, at the most during the night when the VD drops below 1.5.
Irrigation and fertilization
Lighted is more or less equal to unlighted. An older plant just consumes less water. The dripping times must be adjusted accordingly. With a generative crop mode one should aim for 8-10% reduction. Possibly with the help of a night cycle. The cycles must not be made too big. To come back frequently with dripping, one should think of cycles of 150-200 cc / m2 during the day. Try to keep the EC at 4 in the drainage water to keep growth and freshness in the plant.
Go for growth so give plenty of NO3 and K. Please note that if the K irrigation is too high, you will have to ensure the Ca intake to prevent the occurrence of tip rot.
Strive for a 1-3 points higher K irrigation than Ca. Give extra Ca when an extremely warm period is announced.
Diseases and pests
Tuta absoluta is a hot item in some areas. Nesidiocoris causes a lot of failure, although this is not directly a problem with the loosely harvested plum tomatoes.
Diffuse coating
With the lighted crops, there already is a diffuse coating on the greenhouse. If this is not yet the case and we plant in August at the latest, it is recommended to apply a normal coating to the greenhouse. This facilitates cultivation change and the quality of the last fruits.
Syngenta
www.syngenta.nlFrank van Antwerpen
+31 (0)6 51 23 55 15