Completo: growing tips October 2019

Early planting dates
By the Completo cultures of the earliest planting date, we harvest in the meantime at the 7th truss while the 14th truss is flowering. We see nice trusses with tomatoes and all the clusters have at least 10 fruits on it and therefore the plants are heavy. At the top of the plant, you didn’t see the high plant load. The plants have still enough power what expresses itself in the thickness of the top and the purple color. The leaves are too long, but the balance looks not so bad, however, more fruit growth possible is.  Trusses are nice curled, but the flowers develop bigger and vegetative, till now almost all the flowers are fertilized, this remains a point of attention.

Vigor at Completo
We continue to see the enormous vigor at Completo. This contains also the potential of this variety, provided that we convert that into fruits. The balance between fruits and vegetative parts (leaf, stem/growth top, and roots) is important. For the next period, we can influence the balance to the generative site by reducing the LAI. In the summertime, we need leaves for cooling by evaporation and therefore a higher LAI. Now in the autumn time, there is less radiation and the intensity is much lower, the main function of the leave is now photosynthesis.

For the coming period, 12 leaves (> 50 cm) is enough. Start reducing the LAI by removing a leaf in the top, remove the leaf above the truss than the truss become also more light and temperature. This also benefits the growth of the truss, so it works double. Define the desired LAI by de-leafing. Dependent on the desired LAI it is for your employees easy the keep two or three green trusses out of the leaves. Try to keep a weekly rhythm of de-leafing. Look at the position of the interlight after de-leafing, the remaining leaves should catch the light. The leaves are expected to become shorter as they get closer to the HPS lamps.

Temperature and light
Take care of the balance between temperature and light. Use therefor this rule of thumb: A plant us 100 Joule for growing and each truss need also 100 at a temperature of 17,5 degree.  If you have more light you should increase the temperature 1 degree for every 300 Joule.  So, for example, a plant with 7 trusses need 1100 Joule by 18,5 degree. There should also be a balance between flowering speed and ripening speed. The ripening speed should be about the flowering speed. A delayed ripening speed provided a higher plant load and more energy demand of the crop, and that gives a plant with a thin top. Therefore, take care of a good horizontal temperature gradient. Put in enough min pipe temperature when the lamps are on, so you bring heat and speed by the growing fruits.  The temperature above defines the flowering speed, try to have one truss per week in the next period. The temperature is influenced by the lamps, especially the HPS lamps give a lot of radiation head. On the other way, outside circumstances have a lot of influence for example clear sky or cloudy. By closing the screens, you can prevent cool heads.

Truss and flower quality
For truss and flower quality the humidity stays important. Steer the humidity by opening the windows to remove the moisture out of your greenhouse. Helpful can look at the absolute humidity, put it in your graphic, if de value increase than there comes more moisture in the air if its decrease there comes less moisture in the greenhouse air. An absolute humidity of 16 is the maximum. For a nice generative plant, it is important to make the head of the plant dark green at the end of the day for shorter leaves and more generative flowers. To realize this, you can put in more heat at the end of the day to stimulate the evaporation. It is very helpful to close the screens for the last 2 hours for 80% with constant pipe temperature, and a bigger window gap.

Water strategy
Start watering in the lighted night by filling on the water content in the slabs.  This prevents pumping up the plants with water. Then 2 hours after sunrise (later a fixed time in the morning) try to get drain after 3 big shots of watering. After the first drain gives water by smaller shots with around 30% of drainage. In totally 20% over the whole day is good. The stop time define the water content degrease in the night, this should be around 15% for a powerful/(vegetative) crop.

Now, most of the crops have a mature fruit load, so the energy demand is high. The outside radiation decreases quickly, so it is important to add more and more artificial light. Build the hours of artificial light up from the end of the natural day till the beginning of the day. Keep in mind that tomato flowers start closing after 10 till 12 hours after putting on the light. Before the flower closing, they must be pollinated by the bumblebees. For orientation, a bumblebee needs at least 56 Watt sunlight and that must be realized within that 10 hours. If there is not enough sunlight in wintertime pollinate the flowers than manually.

Although Completo is resistant against mildew we see it in the crops. The strong changing weather conditions make the plants more susceptible. By mildew is preventive combat important and easier than fight against an infection of mildew. The preventive combat gives a conflict with de building up of a good Macrolophus population. Scout therefor weekly and feed the Macrolophus more supplementary.

Good luck with Completo!

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