Seedlings in most greenhouses continue to progress quite well. To date, very few problems have been reported.
Seedlings in a dry tray greenhouse on May 6, 2014.
Symptoms of cold injury to seedlings continue to be seen in both tray and muckbed greenhouses.
Now is the time that nitrogen deficiency can sometimes be seen in muckbed seedbeds, as was the case in a greenhouse we visited late last week. Nitrogen deficiency is often related to overwatering and/or mixing the muck layer with the sand underneath when preparing the greenhouse.
Nitrogen deficient seedlings are often observed to be in patches in muckbed greenhouses where the seedlings are slower growing or have almost stopped growing and are quite pale in colour. Often the roots of these seedlings are white and very well developed even though the seedlings are still quite small. Application of nitrogen, preferably in the nitrate form, will be needed to get the seedlings growing again. Rates and application frequency are provided in OMAF & MRA Publication 842.
All growers should be on the lookout for cutworm feeding in their greenhouses. In a very short time, significant damage can be caused by these pests. Registered products recommended for control of cutworms in greenhouses can be found in OMAF & MRA Publication 843.
Fumigation started on a few farms earlier this week. The soil temperature measured at 15-20 cm (6-8 in) deep in a worked field that was prepared for fumigation was 11.5 ⁰C (53°F) in the mid-afternoon on Tuesday, May 6. The air temperature at the time was close to 17⁰C. Judging from the current forecast, it is expected that the day-time air temperature will be similar or higher over the next 5 days.