Upcoming Events/Perennia Updates
Below is a summary of some of the industry events that are coming up in the next few weeks! The events listed below are primarily hosted by Perennia, and more information on each of them can be found here.
- TunnelTalk (virtual webinar series)
- August 11 - Virtual Office Hours
- Bring questions, comments and queries to discuss with myself and your peers! This session is all yours to chat about all things protected production
- OFCAF Field Day - Adoption and Agronomy of Cover Cropping for All Systems
- September 4, 10 AM- 3PM
- Perennia Field House - Cambridge
- Integrating Beneficial Insects into High Tunnel Production
- September 5, 10 AM - 12 PM
- Webster Farms
Weather Updates
Solar Radiation
Table 1 recaps the average light levels per day, from July 1- July 31 across the province. These numbers reflect the full sun we have been experiencing for a number of weeks now. In addition, areas of the province have experienced little-to-no rain, and frequent winds, contributing to the dry conditions that come with minimal cloud cover.
This information was pulled from the Farm Weather Map. I will continue to provide these updates every month, and will make year-to-year comparisons as that data becomes available. If you aren't seeing your area represented, the solar radiation layer is accessible to everyone who has an account on Farm Data Tools
Table 1. Average solar radiation per day, through July 2025.
|
Location |
Average
Solar Radiation (W/m2) |
|
Kentville
(NSW104) |
234.42 |
|
Belmont
(NSW087) |
226.57 |
|
Nappan
(NSW103) |
229.70 |
|
New
France (NSW075) |
241.88 |
|
Glen Tosh
(NSW050) |
220.11 |
|
New Ross
(NSW106) |
248.76 |
|
East
Kemptville (NSW025) |
231.30 |
Seasonal Considerations: Dealing with Hot Weather
What can we do to try and mitigate the impact of significant sunshine and temperatures we have been experiencing the last few weeks?
-Water is our best friend right now. Transpiration, which happens when water moves from the plant back out into the atmosphere, is the main mechanism that plants cool themselves. If there is a shortage in water, the leaves are much more susceptible to overheating. Overheating translates to less efficient photosynthesis, weakens the plants themselves, and decreases yield quality/quantity
water should be applied as close to the roots as possible during the peak parts of the day, so that plants have readily available water
-Opt for drippers/drip tape wherever possible when watering your crop. This is the most efficient way to deliver water to our plants, with minimal lost to the surrounding air during application
-We want to keep our air moving. Within the greenhouse, this prevents the creation of hot, stagnant pockets in and around the plants. Air movement is going to help to draw water from the soil, and up through the plants, which will reduce leaf/plant temperature. If there is no moisture drawn up and through the plant, even if it is available to the roots, it will not help keep the plant cool. This is best done with fans! If we see light movement in the canopy, then we have done well with our air movement. We also want to see air exchange with the outside air. This will help to flush out excess temperature and humidity, as well as replenish CO2. This is best done using vents in the tops of our end walls, but also roll-up sides and roof vents.
-Monitor our humidity as well as our indoor temperatures! Temperature and humidity both play a role in successful plant production, and if we can keep the values appropriately paired, we are doing the crop a huge favour. Low temperatures and high humidity are a recipe for disaster, as is high temperatures with very low humidity. Where we can't control the temperature, we can at least make sure that the other growing parameters are matched up to reduce the impact on crop health
A few (more involved) changes to our greenhouses we can make if things are just much to toasty:
-installation of shade cloth or white wash on the outside of our greenhouses
-roll out a lightly covered mulch/ground cover in the greenhouse. Black ground cover is going to contribute a lot of additional heat where we don't need it right now
Production Tidbits: Pruning Matters!
Tomato pruning on indeterminate varieties has a lot of benefits for the plants, and the quality/size of the fruits harvested. While it is important for managing the resources within the plant, as well as managing pest and disease outbreaks, it also has implications on our fruit production and ripening.
We recently acquired a thermal camera, which can give really valuable insight into what is happening within our protected spaces. I took this out a few weeks ago, just to get a sense of what can be captured with a tool like this.
One of the things that really struck me was the temperature of the fruit, and how widely that varied between exposed fruit, and those that were protected with the canopy. Fruits that were fully exposed to the sun were significantly hotter compared to those that had some shade from overhead leaves. These photos were taken in the same area of the greenhouse within a few minutes of one another.
Figure 1. The king fruit on an exposed cluster of cherry tomatoes, reading 29.5C on the thermal camera. Photo credit Talia Plaskett
Figure 2. The recorded temperatures of two tomato clusters under the shade of the overhead canopy. Photo credit Talia Plaskett
That being said, there is a time and place where we want our fruit to have a more direct sunlight on them, namely once they are sized up, and ready to start ripening! What we want to try and avoid if we can, is having these really early/young fruits getting the full brunt of the sunlight on them before they have had a chance to develop. This can lead to things like sunscald, which renders a fruit unmarketable.
How can we control this? Strategic pruning! Here are a few of my favourite tips when it comes to cleaning up indeterminate high tunnel tomato plants:
- Consider where the fruit/flower clusters are in relation to the leaves
- Try to keep younger fruit and flower clusters shaded with overhanging leaves to reduce the risk of sunscald until they are ready to ripen.
- I like to aim to have 2 fully expanded leaves for each flower/fruit cluster on the plant
- ex, I have 3 fully developed clusters, 1 set of flowers just set, and a new set of flowers just opening. I count this as 5 clusters, meaning i would want 10 fully expanded leaves on this plant. I will count up from the bottom of the plant, stopping once we get into new tissue coming out of the growing point
- Less than this can result in a plant that runs out of 'steam' before the end of your season. Leaves fuel fruit production (but we don't want to overdo it either!)
- Pruning can happen throughout the plant, and doesn't have to be restricted to moving from the bottom of the vine and upwards
- This is a good thing to do to a degree - if the oldest fruit cluster is exposed to the sun, that's a good thing at this stage in the game. It isn't uncommon to have the second oldest cluster showing as well.
- Assessing the full structure of the plant is a good strategy to maintain air movement around the whole of the plant, not just the bottom parts of the stem. If you notice that there are particularly dense areas in the canopy, those can be prioritized for removal instead of stripping from the bottom upwards.
- Try not to remove more than 2-3 leaves at one time - we don't want to stress the plant too much
- if we are behind on pruning, break up your removals over a two weeks instead of doing it all at once
- Removal should happen early in the morning on hot, sunny days (not an issue this year)
- we want the wound to dry up as much as possible before night time. Our temperatures are dropping quite a bit in the evening, making condensation and excess water overnight a possibility that can result in heavy disease if left unchecked
Pest and Disease: Potato leafhoppers
2025 is proving to be the year of the potato leafhoppers! While this pest is commonly found in horticulture crops, the conditions this year seem to warrant a much higher presence of hoppers than what has been observed over the last few years.
Leaf hoppers are considered piercing/sucking insects, meaning they are creating wounds in the plant, and extracting sugars/nutrients that the plants have created. Potato leafhopper is different than most leafhopper species, as enzymes in their saliva cause abnormal cell growth, as well as block water and nutrient movement in the leaves. When left unchecked, this can have a significant impact on plant vigour. The younger stages of leaf hoppers can be found on the underside of leaves, while the adults are hard to miss! They can be quite mobile in the canopy, and you will likely see them springing around as you jostle the plants around. Damage caused by potato leafhopper is generally exaggerated in drought-like conditions.
Figure 4. A leaf hopper observed on the top of a bean plant. Photo credit Talia Plaskett
Figure 5. A classic example of damage cased by leaf hoppers, known as 'hopper burn'. Photo credit goes to Greg Varner (Michigan State University website).
Potato leafhopper is on the feed list for a number of predators, but they typically are not able to keep numbers down in high infestation years. Beneficial predators and parasitoid wasps only play a minor role in controlling these populations...that being said, I am not an entomologist, so it is worth asking your beneficial insect dealer for their two cents on this if you are facing an infestation on your farm!
There are a handful of chemical control options available for those following conventional pest management strategies.
___________________________________________________________
This is by no means the only uninvited guests we should be looking out for. If you have any questions or concerns regarding pests, diseases, or plant production in general, don't hesitate to reach out!
Recent Uploads:
Soil Health Results Workshop - A recording of an event back in March 2025, Horticulture Nova Scotia reports on the progress of the new Biological Nitrogen Analysis (BNA) test developed by the NSDA provincial lab and Dalhousie Faculty of Agriculture. This can be used to understand the amount of nitrogen that is available in our soils.
Irrigating a Container Crop: Checks and Balances - A factsheet outlining the way we can monitor and fine-tune our irrigation/fertigation schedules in container crops! EC and pH can give us a lot of information about what our plants need.
That's all for now! If you have any questions, feel free to reach out :)
Happy growing everyone!
Talia (tplaskett@perennia.ca)
