Viper newsletter week 7, 2010

This newsletter will cover following:

1. Setting under lower light conditions.
2. Getting the strings on the plants at the right time.
3. After 1st set, now what to do?
4. New yellow blocky pepper from Enza.

Light levels have been lower in January 2010 compared to the average normally received. The first 2 weeks was not significant lower, but week 3 was extremely low. The biggest issue with low light levels is, that we did have many days continuously with 200 joules daily, and then suddenly we receive 800 to 1000 joule the next day. It is a big change for many plants, and a very stressful situation. I have seen different strategies used during the dark period, some growers lower their 24 hours average, all is very careful with irrigation, and some use very aggressive pruning off shoots, to use all energy in the flowers and setting.

Viper do appreciate adjustment of 24 hours average during low light conditions, be careful that you don’t get too low, under 19,0-19,5c̊. It will slow down the development of the flowers and as well also create large flowers = pure quality later on. And also consider your setting for when the sun finally comes through, be careful with too high temperature in the afternoon, over 25-27c̊ can be too much and make the flowers fall off as well. Viper do also work well with Prenight settings around 18-19c̊ at the moment, a short drop for few hours is enough. If you have installed fixed plastic screen, consider that temperature might drop slower, follow the temperature on the graphs on you climate computer, and maybe except that the drop takes a bit longer time, instead of venting too much.



In general I have seen anything between 2 to 4 fruits pr 2 stem on first setting, all depending on planting dates.

In general I have seen anything between 2 to 4 fruits pr 2 stem on first setting, all depending on planting dates. Early planting should use setting in second internode and up, I would aim for 4 fruits on first set. Late planters in end of january and early february can consider setting to start in first internode, but be carefull not to load up the plant with 6 fruits pr 2 stem, if Viper gets too generativ in the start it can create issues with fruit quaity later on, so aim for 4 fruits pr 2 stem.

Crop work for shoot pruning should be done on time during low light conditions; you want all energy to go to the flowers. Some growers even prune shoots on a weekly routine during low light conditions.
We see a lot of different ways of tying/clipping the string onto to the plants. Keep in mind that you want to use all available light, so it is important to get the plants separated. Also to avoid stretching on the inside shoot, it is important to keep the shoots separated as soon as possible. Keep the sting tight, so the plants don’t ‘fall out into rows’ later on. Some growers are using green and white strings, other just white strings. And it really doesn’t matter, if you have experienced crop workers they will know the system with 2 heads (on regular double stem system), where if you are using inexperienced workers, it might be easier to work with 2 colors, to understand the system.

We have often seen growers use the clips to hold the string, and again it is probably an easier system for inexperienced workers. From earlier years we had some concerns if the clips were too small, and that the stem would get too big for the clips. But the last year we didn’t really see any issues regarding this, you have to be careful where you position the clip, not right under a note where you are planning setting, the clips can give the fruit scares. Tying is still used a many facilities as well, it is a bit more difficult to get the string tight on the plant, but for experienced workers it should not be an issues, and the benefit is that you don’t have to worry about scars on fruits.

After first set, you will have to think about growing vegetative for a period, it very much depend on how well the first set came on. You might have to continue using Prenight, in case of very low fruit load on first set. In general I would not recommend allowing any setting on side shoots, but if you first set missed, you could consider letting the plant set some fruit on side shoots. This only applies if you totally missed all fruits on first set, and now have 3-4 internodes empty.  This is the only time you should use fruits on side shoots, and it is only used as an emergency tool to keep the plant in balance.
Co² levels should be kept around 600 to 800 ppm, again be careful and stop all co² supply to greenhouse in early afternoon, so levels don’t build up over the night. Too high Co² can also be stressful and make the flowers fall off, especially if it is under low light levels.

You might have a trial area of E 41 2493 in your own greenhouse. Please pay some attention to how easy this number is setting during low light levels.

For growers, who don’t have this trial, I can inform that it is a yellow blocky pepper. It did very well under trials in Ontario and Holland last year, and we have some large trial areas this season.
Plant character is a short plant, smaller leaf area but spread very well so all available light is used. Setting comes on very easy, first as well second. After second setting, it is critical to keep the growth going in the plant, as well also when first flush is coming off. Production in a small area in 2009 was 27 kg pr m², and the lowest fruit average size we saw during the season was 245 gram toward the end of the season. Shelf life test was done as well with very good results. I will keep you all updated, but again if you have trials of this number in your facility, I recommend you to notice the setting as well later on the shelf life on the fruits.