March 2024 Newsletter

Upcoming Events

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.

• Pesticide Information impacting Horticulture and Field Crops - March 5, 2024
• Nematode and Soil Health Convention - March 7, 2024
• TunnelTalk
• March 13- Reviewing the Efficacy of Botrytis control products w. Dr. Anissa Poleatewich
• April 3 - Pollination w. Andrea Keddy

• 2024 Berry Primer - March 21, 2024
• South Shore Ag Day - March 25, 2024
• Horticulture Nova Scotia presents 'Soil Moisture Tools' - April 9, 2024
• This will not be a greenhouse-specific event, but should prove valuable for outdoor veg producers!

Program Updates

On Farm Climate Action Fund (OFCAF) Extended Funding for 2024-2025!

Perennia is excited to announce that our agreement with AAFC for an additional year of programming has been solidified! Applications for 2024 will open Monday, March 4. This is an extension of the program that was offered in 2022 and 2023, so we are still focused on supporting implementation relating to these three best management practices:

    Nitrogen Management

    Cover Cropping

    Rotational Grazing

For any questions about OFCAF, your eligibility, or anything else program related, reach out to our OFCAF technical lead, Georgia Lewis!

2023 Season Response Program

This program is intended to support farmers impacted by extreme weather and wildfires in 2023. It builds on other business risk management programs that were available last year, intending to help those still recovering, or who were not covered by other support programs. The new program covers crop damage and yield loss that was a direct result of flooding, excessive preceiptiation or wildfire damage. Other losses such as farm infrastructure, supply losses, and the cost of re-establishing fields may qualify and will be considered. 

THE DEADLINE TO APPLY IS MARCH 13, 2024. Click here for more details.

Hurricane Fiona Supplemental Relief Program

Check out your eligibility here!

Seasonal Considerations

With crop planning underway, its important to start thinking about our nutrient management plans and assessing which amendments we want to use this season. We have talked a lot about nitrogen management last year, and the implications to greenhouse soil health when we don't look at the entire breakdown of our amendments. With a heavy emphasis on hitting the target nitrogen levels for our main cash crops, it can be easy to overlook the amount of phosphorus, calcium, magnesium and sodium that are also being added into the system. Without additional management plans in place, these nutrients will accumulate exponentially in our greenhouse soils, making it increasingly difficult to produce a healthy and productive crop. 

Check out the webinars we hosted with Judson Reid last year talking about this very issue, or our summary fact sheet:

-Webinar recording: Managing nitrogen in protected, soil-based systems

-Webinar recording: Planning for split applications 

-Fact sheet: Managing Greenhouse Soils through Split N Application

Considering a new supplier of compost this year? Check out our compost analysis fact sheet, which provides a breakdown of what our reports are telling us, and what it means for our farm. 

Production Tidbits: Germination!

A few years ago, I played around with different combinations of heating mats, and domes, to assess their impact on germination uniformity and success. Here's what I found:

For the first round, the room was set to 70F (21C)

Results 7 days post seeding: 

•     No seeds had germinated in the control treatment, or the heat mat treatment
•     Staggered germination of 5/36 tomatoes in the plastic dome treatment
•     Consistent emergence of 29/36 tomatoes in the heat mat + plastic dome treatment

A few other noteworthy comments from the first round:

• Treatments without a dome were much more prone to drying out compared to those with domes. It required a more frequent application of water to the top of the soil to make sure seeds had the moisture they needed
• The combination of the heat mat and the plastic dome saw much earlier emergence compared to the plastic dome on its own

For the second round, the room was set to 80F (26.7C) 

Results 7 days post seeding: 

• 10/36 seeds germinated in the control treatment
• 0/36 seeds germinated in the heat mat treatment
• 28/36 tomatoes germinated in the plastic dome treatment
• 19/36 tomatoes in the heat mat + plastic dome treatment

The plot thickens!

In this round, the added humidity around the seeds was the most beneficial in aiding successful and uniform germination. Because the temperature was considerably higher for this round, the heat mat was not advantageous to germination and likely resulted in the potting mix drying out at an accelerated rate compared to the control treatment. 

What can we take from this?

• As with any input, it will only be worthwhile if it is implemented appropriately. Adding a heat mat to a cooler temperature germination space will give the seeds the boost they need for more successful emergence. Adding a heat mat to a warm temperature germination space is not going to give you an advantage, because temperature is not the limiting factor in this scenario. 
• The domes were a very handy tool for creating a more humid space around the seeds, and reducing the amount of water that needed to be added to the system through the process. That being said...the dome should be removed once the majority of the seeds have germinated. Many post-emergence diseases do thrive in warm and wet environments, and we do not want to encourage their establishment. Do not wait for the plants to hit the roof of the dome before removing it. Once you see >60% of those stems and cotyledons break through the soil, it is time to remove the dome. 
• It is cheaper to heat up a dome/heat mat system than it is to keep an entire greenhouse at 80F for the duration of emergence and early seedling life. 
• For those of you who have trouble maintaining consistent temperatures in your germination space, consider adding both. From the first round of trialing, the heat mat on its own was not successful at boosting the quality of the transplants. While we did see some plants pop up under the dome treatment, the quality and consistency across treatment 4 (dome + heat mat) was significantly better. 
• If properly cleaned and stored, heat mats and domes can be re-used from year to year, making the most of your initial investment.

Feature Pest/Disease

With transplant production top of mind, damping off seems like an appropriate choice for this months feature focus. 

Here are a few things we can do to reduce the degree of damping off we see in our seedlings:

1) Use clean potting materials! Seeding trays, carrier trays, domes, heating mats, gloves, shovels, and everything that can be re-used between seasons should be CLEANED before we get started. Ideally this includes a wash with soapy water, left to air dry, then followed by a sterilizing agent, to make sure there are no stow-aways year to year, waiting for fresh young roots to start growing again.

2) Careful moisture monitoring! Potting mixes are notorious for having different water holding capacities. Fine, small particle mixes are very effective at holding onto water for long periods of time, which requires less watering by you. It can also mean that your plant roots are constantly surrounded by water, with no opportunity to dry out or access air-filled pores, making them prone to fungal infection. Larger particle mixes are very good at draining water, meaning your plants may need more frequent water application compared to others. Ideally your potting mix consists of both fine and larger particle sizes, facilitating both drainage and some water holding capacity. 

The colour of the potting mix surface can be misleading in deciding whether or not the plants need more water. The weight of a tray or pot is a great indication of how much water your substrate is holding, and whether more needs to be applied. 

3) Consider preventative product applications! There are many biological based products which have proved very efficacious against early season fungal disease. Agents such as Trichoderma spp. will coat the new roots as they grow, and provide competition for any problematic agents that are also present in your potting mix. These products can be applied multiple times, according to label instructions, during transplant production and at the time of transplanting, so keep your eye out for these if you are wanting the extra assurance for strong, healthy transplants!

4) Make sure that your seeding tray/propagation setup allows for drainage. A substrate that is not allowed to drain will cause more headaches than solutions.

5) Environmental monitoring! Excess humidity, whether that's from standing water on the floor/carrier trays, or through a covering left on too long, can be hugely problematic. We want some humidity to give our plants everything they need as they set the stage for our 2024 crops, but its important to manage water in all parts of your germination space, not just the potting mix itself. 

Recent Uploads

• Ask Us Anything Webinar - Cover Cropping and Split N Application in Greenhouses
• TunnelTalk - Nutrient Management Planning in Greenhouses

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That's all for now! If you have any questions, feel free to reach out to your extension specialist.

Happy growing everyone!

-Talia 

Tunnel Talk(s) in 2024

 Introducing the latest addition to Perennia’s extension portfolio, TunnelTalk! 

This series aims to provide a recurring virtual space for producers of all shapes and sizes to come together and discuss all things protected agriculture. The main topic for discussion will vary month to month, with outside expertise on relevant topics, grower roundtables, shared experiences with techniques and technology, and group troubleshooting. This series of meetings is intended to be driven by grower feedback, so if there are any topics you'd like to see featured in these meetings, don't hesitate to communicate them! 

Upcoming sessions:

January 10 from 8:30-9:30 with Guest Speaker Anna Teston

The main topic of discussion will be anaerobic soil disinfestation (ASD). Join our in-house protected crop specialist and Anna Teston to hear about her research in this space and experience conducting ASD on farm. Anna is a Research Plant Pathologist with the United States Department of Agriculture Agricultural Research Service. Her research program focuses on developing disease management strategies for horticultural crops in controlled environment agriculture, including high tunnels. She has been studying ways to reduce the impacts of soilborne diseases in high tunnels, including the use of anaerobic soil disinfestation, grafting and soil steaming.

This session will start off with a presentation, followed by participant questions. As always, there will be space for a general round table to voice concerns/pain points/success stories amongst the group after the main presentation.

February 7 from 8:30 - 9:30 with Guest Speaker Caitlin McCavour

The main topic of discussion will be nutrient management planning in soil-based systems. Join our in-house protected crop specialist and soil specialist for a discussion on some of the unique challenges tunnel and greenhouse spaces present when it comes to nutrient management planning. This session will start off with a presentation from Caitlin McCavour, followed by grower questions. As always, there will be space for a general round table to voice concerns/pain points/success stories amongst the group. 

March 13 from 8:30 - 9:30 with Guest Speaker Dr. Anissa Poleatewich

Dr. Anissa Poleatewich will summarize her work examining biological-based product efficacy against botrytis! 

Stay tuned for quarterly updates on upcoming dates and topics. For registration and question submission, visit our website!

Hope to see you there

-Talia 

Cover Cropping Question Bonanza!

Interested in an opportunity to discuss your farm-specific cover crop questions with a Perennia specialist? Check out two upcoming virtual events, where the entire session is driven by YOU! Questions can be submitted beforehand, or live during the event, as your ideas are sparked by discussion happening in real time. 

'Cover Crops - Ask Us Anything!' taking place December 13 @ Noon 

Did you try cover cropping for the first time in 2023? Been doing it for a while but struggled with the wet conditions? Whatever your questions about cover crops, we’ve got answers!  

As a follow-up to last year’s Cover Crops: Ask Us Anything webinar, join Perennia cover crop experts Berry Specialist Sonny Murray and Fields Crops Specialist Caitlin Congdon for a live question-and-answer webinar about cover crops! Attendees are encouraged to submit questions in advance and join us on December 13 at noon to hear the answers and tune into the discussion.

Registration details can be found here!

'Cover Crops and Split Nutrient Application - Ask Us Anything! (Protected Ag Edition)' taking place February 6 @ Noon

This session takes a look at cover cropping and split nutrient applications in protected spaces! A spin-off inspired by the session listed above, this is a great opportunity to ask any questions you may have about implementing these practices in your tunnels. 

Join Perennia’s subject experts, Protected Crop Specialist Talia Plaskett, Berry Specialist Sonny Murry and Fields Crops Specialist Caitlin Congdon, for a live question-and-answer webinar! We will also be featuring two season farmers as well, to give their two cents on their own experience, and comment on practice feasibility. Where cover crops are a relatively new practice to protected spaces, we still have a lot to learn. The more perspectives we can bring to the table to come up with a solution, the better! 

Attendees are encouraged to submit questions in advance and join us live on February 6 at noon to hear the answers and tune into the discussion. Registration information can be found here!

Looking forward to seeing you there!

-Talia

Interpreting a Compost Analysis

The incorporation of compost into your production spaces is a great way to recycle nutrients and carbon back into the soil, turning waste into something that will feed future crops and soil microbes. The variety of materials incorporated into compost, however, is highly variable. Plant residue, municipal solid waste, food processing waste, pulp or paper mill solids, manure and seafood wastes are all contenders for being included in a compost. The range of materials, each with their own broad ranges of nutrient concentrations, makes it a highly inconsistent product between batches, even where the supplier remains consistent. This variation in composition is going to have implications for nutrient management planning year to year - we can't necessarily apply the same volume from year to year and expect the same impact on our soils. 

In order to approach our nutrient management and compost applications with increased accuracy, it is recommended to submit compost samples for analysis. Nova Scotia's provincial lab services offer this as an option, and the report will break down the nutritional composition of the compost for next season's planning. Once we can better quantify the amount of nitrogen (and other key nutrients) in the compost, application volumes and a plan for additional supplementation throughout the growing season can be put together to meet the crop needs, and reduce accidental over-fertilization. 

For greenhouse soils, where all overhead precipitation has been excluded, compost analysis is especially important. Some composts tend to run high in salts (ex. calcium, magnesium etc), and while these are crucial nutrients for crop production, it is important that they are not being over-supplied to the soils. With a lack of a seasonal reset via rain and snow in protected spaces, these salts can accumulate quickly over time, impacting crop health and productivity. 

Now that we have the data...what does it mean?!

The Department of Agriculture has an interpretation document outlining the line items included in a compost analysis report and the impact that each nutrient has on crop production. Once you have a good understanding of what is included in the report, Perennia has created a fact sheet that provides further information on some of the metrics included, and the implications that these metrics have on our nutrient management plan. Below is a brief summary of some of the information presented in the factsheet, but I highly recommend you check it out for yourselves! 

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Finished composts typically contain low levels of a wide variety of nutrients (though this is highly dependent on the materials included in the mix). This lower level of nutrients can translate to a tendency to apply large volumes of compost, however this can lead to excessive levels of certain nutrients in the soil in some cases. It is typically recommended that compost is not the sole fertility source for crops, but one of a handful of additives that come together to provide the target nutrient ranges for the crop in question. 

C:N Ratios

The amount of carbon present in a compost, in relation to nitrogen, impacts nutrient cycling, and how quickly nutrients will become plant available. Composts typically range from 8:1 - 30:1. If your compost has a ratio:

•  >40:1, there is a good chance that any nitrogen that is present in the soil/compost will be 'tied up' through the process of breaking down carbon. This can lead to nitrogen deficiencies in your crop.
• 12-22:1, there is more nitrogen available than the microbes need, meaning it will become plant available more readily
• 25-32:1, it will slowly become plant available over the course of a few years.

Nitrogen

The provincial lab analysis of compost reports on total nitrogen in the sample, however nitrogen has many forms in compost. 'Organic nitrogen', which is the nitrogen included in microbial, animal and plant tissues, is not immediately plant available. It must be mineralized in the N cycle before a plant is able to take it up and use it for growth. The rate of mineralization is difficult to forecast, as it is dependent on a handful of variables (temperature, moisture, C:N ratio of the compost). When compost is the only source of nitrogen in a production system, it is challenging to match the times of peak demand for the crop, with the availability of high amounts of useable (i.e. mineral) N. 

'Mineral nitrogen', specifically ammonium-nitrogen (NH4-N) and nitrate-nitrogen (NO3-N), are the plant-available forms of nitrogen. While these are key forms for plant production, they are easily lost to the environment if they aren't immediately taken up.

How do we know the amount of available nitrogen that is present in our compost analysis? Low N composts typically have low mineral (readily available) nitrogen. High N composts usually carry a fair amount of NO3-N, which is immediately plant available. Take a look at the table below, which estimates the breakdown of organic and mineral N based on your C:N ratio, and the total N (% dry weight). This chart was taken from Perennia's fact sheet linked above, and sheds some light on the percentage of organic, or plant -unavailable, nitrogen in a compost. 

From here, we can calculate how much compost we need to add in addition to our other amendments, in order to meet the target N needs of the crop in question. 

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Utilizing and understanding the tools available to us is a key step in maximizing on-farm productivity, and the inputs invested on the farm. Compost analysis, along with soil tests and water tests, are great ways to quantify and characterize our key production components, and figure out how they can work together to hit our crop-specific nutrient targets without overshooting them. 

For those who are interested in better understanding their compost analysis results, check out Perennia's fact sheet here, or contact your commodity specialist for further discussion! 

-Talia 

Finishing up 2023

 As we finish up our 2023 growing seasons, it is time to re-visit our standard cleaning procedures. Throwing out the old and preparing for the new is one of the most important components to protected production.

While this is going to look different for those in soil-based systems compared to those who are set up hydroponically, there are some key practices that can be adapted to any protected space:

1. Removing ALL organic matter from the greenhouse, and greenhouse vicinity
• dried up leaves, old soil, dirty pots and growing supplies are perfect hiding spots for pests and disease to overwinter. Its important that you eliminate as much potential habitat and food source as possible
• Don't hesitate to do this in stages. Clean out the big stuff, and come back a second and third time to get rid of the bits and pieces that were not picked up the first few times. 
• Do not leave piles of plant material or old soil next to your greenhouse. As much as these serve as habits inside the production space, they will do the exact same thing outside. No matter how well the inside is cleaned, if you have a major source of insects just steps away from the greenhouse...there will be problems
2. Collect all old growing supplies from the year, and remove from the space for cleaning. Pots, carrier trays, pruners, clips, support stakes/string etc. should be dealt with to reduce pathogen and pest load into the new production cycle. Pots, carrier trays and pruners can all be sterilized and re-used, but be aware of the cleaning agent used here - some are going to cause more harm than good! Wooden stakes, while tempting to re-use these, cannot properly be sterilized because they are highly porous. Disease transfer from year to year from re-using stakes is possible.
3. Consider swapping out ground cover if you are using something more substantial than plastic mulch! While this isn't something typically tackled on a yearly basis, following a heavy disease year it can be worth considering getting a new cover put over the ground. If you are considering this, remove the old cover before going forward with suds and sanitizer! That way your ground layer will be scrubbed back to a base layer of clean, and you can be confident that nothing is hiding out in tiny cracks and crevices throughout the old ground cover.
4. Lets get soapy!
• Giving all growing surfaces a soapy scrub is going to grab hold of any bacterial, viral and fungal agents that are still in the space and wash them away. 
• The best strategy for washing a greenhouse is to start at the top and work down - and this includes your ceiling! Failure to wash the top of the grow space creates a disease bank that can literally rain down on your future crop.
• Once you have applied your soap, give the production space a thorough rinse and allow it to air dry
5. Once you have allowed the space to airdry after cleaning, it is time to bring in the big guns- Sanitizer! There are a lot of sanitizers on the market to chose from, but they do have a few things in common:
• Contact time is important. Different products have different required contact times in order to be effective. Be sure to check what the required contact time is for your product of choice, and do your best to adhere by that. Otherwise there is no guarantee that the product will sterilize to the degree that you are hoping for
• Organic matter will de-activate sterilizing agents. Any of those leaves or soil bits that got left behind in pots and seeding trays will actually render your product useless. 
• Consider how corrosive your cleaning agent is. Bleach is effective, but does impact the longevity of growing equipment, both for plastics and other materials.
• TEMPERATURE. Sanitizer efficacies significantly decrease at lower temperatures. While it is difficult to justify heating a protected space for cleanout, it is a key factor in maximizing your product efficacy.

Here are a few other considerations for your end-of season wrap-up:

-Once the production space and tools have been cleaned, be conscious of what is coming into the space. Just because you aren't actively growing plants, doesn't mean you are immune to accidental spread! Clean clothes/shoes/growing supplies should be the only thing that enter the space for as long as possible to maintain the clean slate.

-For those who are growing in soil, producers should consider removing plastic on spaces that are not being used for production. The lack of rainwater coming onto your tunnel soils will result in the accumulation of salts in the soil. One of the best ways to tackle this is to allow the snow and rain that come with the winter to run through the soil. Come growing season, this will allow for better uptake and use of supplemented nutrients, and less stress caused by buildup over time. Plastic removal can be a pain, so even doing so every few years is going to be hugely beneficial. For more information on soil salinity in high tunnels, check out this fact sheet!

-Looking to maximize the performance of over-wintered cover crops? Unheated, double poly inflated greenhouses are not going to give enough protection from those cold winter nights. The addition of one or two layers of ground cover can work wonders for your cover crop, reducing large fluctuations in temperature and buffering against cold snaps. It also helps to protect soil moisture for your cover crop. As our day lengths turn around, these plants will see a huge boost in productivity in February and March, increasing the amount of in-house biomass generated to be worked back into the soil before bringing in the cash crop. 

Row cover is best installed after a cold snap or two in the greenhouse space. This should function to kill some of the pests that may still residing in the space, before adding the additional layer of protection

Here's to a fresh start!

Posted by: Talia Plaskett

NEW Guidelines Surrounding the Purchase of Pest Control Products in Protected Spaces

Attention Protected Producers! There is a new national standard on the block.

The Protected Agriculture Stewardship Standards were established to assist protected agriculture operators in the identification and mitigation of risk associated with pesticide application. This set of standards was drafted by a multi-stakeholder committee including CropLife Canada in collaboration provincial and federal grower groups. Health Canada's Pest Management Regulatory Agency (PMRA) and Agriculture and Agri-Food Canada (AAFC) acted in an advisory capacity to guide development of the standards.

The standards apply to any crops grown under structures, such as greenhouses, shade houses, hoop houses, high tunnels, warehouses, containers etc. This new motion requires a certificate in order to purchase any pest control products registered for use in protected spaces effective January 1, 2024. This includes biological-based products, as well as conventional chemistries. 

There are two general streams associated with this new set of standards:

Category 1PA -> Protected Ag Operators using any closed loop irrigation/chemigation systems. A closed loop system is one where any excess irrigation/chemigation liquid delivered to the crop is captured via trough. drainage tile, or other similar conveyance system. Operators using these systems are referred to as Category 1Pa Operators. 

NOTE: warehouse production structures and freight container growing operations with no subterranean plumbing and continuous flooring are excluded from this group

Category 2PA -> Protected Ag Operators not using closed loop irrigation/chemigation systems are referred to as Category 2PA Operators. 

The path forward looks different depending on which of the two streams your particular farm falls into.

A few additional tidbits:

-For those who have both types of irrigation/chemigation on their farm, a category 2 waiver is not needed. Follow through the path for Category 1PA. 

-For farms that have multiple locations/addresses - 

• A site spanning multiple address that are adjacent to one another will be considered a single site
• Multiple addresses that are NOT adjacent to one another will each be treated as a separate assessment, and a separate registration must be completed. 

-What happens if I am currently a Category 2PA operator, and we install a closed loop system in all/some of our operation?

•     When a category 2 waiver is completed, the operator agrees to terms, including notifying the AWSA of any changes in use, scope, or category. In these cases, the operation should be audited for compliance with the Standards. Once successfully audited, a certificate will be issued which renders the original category 2 waiver redundant. 

Stay tuned for details on an upcoming virtual Q&A session with a representative from CropLife in the next month! This will be a great opportunity to get clarity on the new standards effective January 1, 2024. Deadline to Register is December 31, 2023. 

In the meantime, feel free to explore AWSA's page on the Protected Agriculture Stewardship Standards and the resources provided there. 

-Talia 

Upcoming Tour for Greenhouse Soil Health

 Extra! Extra! Learn All About It!

Judson Reid and Talia Plaskett will be making the rounds in Nova Scotia July 3-July 5 for farmer-guided discussions on soil health in tunnel spaces! These sessions will be primarily focused around nitrogen management, and the crucial considerations to make when selecting nutrient inputs to make sure that we are supporting a healthy and resilient soil system, as well as maximizing the productivity on our target crops. This conversation is easily catered to production that is organic, conventional and everything in-between.  Feel free to bring your most recent soil test and tissue test results for some feedback and general discussion surrounding what those results are telling you.

Where soil health is a complex, multi-dimensional topic, the tour team will also be talking about the use of cover cropping in protected spaces. Where cover crops are hardly a new practice, the inclusion of this concept into tunnel spaces is not as commonly practiced. Cover crops offer a handful of benefits to protected producers, where erosion may not be the primary concern, but they can help facilitate drainage, fix nitrogen directly into the soil, maintain healthy microbial communities, and help to build organic matter in these highly productive, highly utilized spaces. 

The intention of these sessions is to provide a space for current and prospective tunnel producers to talk about soil health, and how protected production can lend to some unique challenges not typically seen in outdoor settings. So grab a friend, and register today for your closest tailgate meeting, for what should make for a very interesting session! 

More information can be found here

Posted by: Talia Plaskett

Managing Nitrogen in Soil-Based, Protected Crops

The first session of our mini-series set the stage on some of the issues we are seeing regarding soil health and long-term resiliency in protected spaces. For those of you who missed the first session, or are interested in revisiting the teachings before building on it in part 2, you can find the full recording here (Managing Nitrogen in Protected, Soil-Based Systems). A summary of some of the information presented is listed below:

One of the re-occurring themes in protected soil production is an accumulation of nutrients, specifically things like Mg, Ca, and K, as a result of large deposits of compost before a cropping season. While these are necessary nutrients for healthy crop production and good quality fruit, too much of a good thing is not always a good thing. Typical supplementation focuses so heavily on achieving a target N value, that a lot of the micronutrients that come along with that N slip by unnoticed.

Not only are we concerned with high levels of certain micronutrients, but also have to be aware of the soil structure itself. One of the soil health indicators we talk a lot about is percent organic matter. While we like to see higher percentages of organic matter, it can come at a cost to other macro- and micro- nutrient availability to the plant when not executed properly. Paying attention to the cation exchange capacity value, or CEC, on a soil test, is important for those who regularly apply compost. While not mentioned in this webinar with Judson, the higher the CEC value, the tighter bond exists between the soil particles and the nutrients, which make it harder to make adjustments to the nutrient composition/balance without significant intervention.

Combine these two factors with the lack of overhead precipitation in tunnels, we see astronomical values of these micronutrients, which are going to contribute to a rising pH, and a significant hinderance on the plant's ability to take up all of the nutrients in the required quantities/balances that the crop needs. Here is an example of the soil test presented in the webinar highlighting this exact trend. The top image highlights a soil that has been supplemented but not to any excessive extent, and the second image highlights how that soil has evolved with continual additions of a compost:

When it comes to the use of compost in protected settings, conducting a compost analysis before application is strongly encouraged, as is yearly soil testing so that we see what is happening in these soils that do not have the same opportunities for drainage as an exposed soil would. Understanding exactly what you are putting into the soil, and how often, is crucial to avoiding buildup to the levels displayed here. Generally when it comes to supplying nutrients to the crop, scenarios that require supplementation are much easier to navigate compared to a heavily loaded and complex soil as what is projected above. The use of fertilizer blends can also contribute to the accumulation of certain nutrients. Consider this - the go-to fertilizer you use in your system is 20-20-20. While that is a great source of nitrogen, your P and K are already very high, and is going to add to the already-existing nutrient load. In soils such as these, single nutrient sources are going to be a much better choice as we attempt to remediate these soils into something that are resilient and will support crop production well into the future.

Given all of this information, what can we do to better balance out our nutrient supplementation to prevent this from happening? One of the best strategies is going to be split nutrient, application throughout the season. This is a much more targeted approach, where we know:

    1) nutritional targets for the crop in question

    2) recent soil tests outlining nutrient composition

    3) BONUS when we consider the long-term nutrient output of supplements such as                      compost or manure

From here, we are able to formulate a plan that sees regularly scheduled nutrient introduction via fertigation into the tunnels, specifically targeted for when the plant needs those nutrients the most. In doing so, we can reduce the loss of nitrogen to the environment, prevent unnecessary buildup that impede production success, maximize the impact that each $$ of fertilizer has on crop performance, and generally contributes to resilient and long-lasting productivity of those greenhouse soils.

Interested in learning how to set yourself up for split applications during the season? Join Judson Reid and Talia Plaskett at noon (AST) on April 13th for a ‘Lunch and Learn’ session on how to set yourself up for split applications of nitrogen throughout the season! This is a great opportunity to help establish the fertigation plan for 2023 and fine-tune your calculator skills to make sure that you are getting the maximum impact for every drop of fertilizer injected into the soil. For more information, or to register for the session, please check out our learning portal.
 

Posted by: Talia Plaskett

 

 

Setting the Stage for 2023

 As we head towards the end of the season, it is time to start thinking about the cleanout process. Throwing out the old and preparing for the new is one of the most important components to protected production.

While this is going to look different for those in soil-based systems compared to those who are set up hydroponically, there are some key messages below that can be adapted for any producer. For those who are growing in soil, producers should consider removing plastic on spaces that are not being used for production. The lack of rainwater coming onto your tunnel soils will result in the accumulation of salts in the soil if left unchecked. One of the best ways to tackle this is to allow the snow and rain that come with the winter to run through the soil. Come growing season, this will allow for better uptake and use of supplemented nutrients, and less stress caused by buildup over time. Plastic removal can be a pain, so even doing so every few years is going to be hugely beneficial where it is not feasible to do more regularly. For more information on soil salinity in high tunnels, check out this fact sheet!

Here are a few key parts to your end-of season wrap-up:

1. Removing ALL organic matter from the greenhouse, and greenhouse vacinity
• dried up leaves, old soil, dirty pots and growing supplies are perfect hiding spots for pests and disease to overwinter. Its important that you eliminate as much potential habitat and food source as possible
• Don't hesitate to do this in stages. Clean out the big stuff, and come back a second and third time to get rid of the bits and pieces that were not picked up the first few times. Vacuums and leaf blowers can be excellent tools for capturing/collecting small organic bits that seem to escape the grasps of a broom
• Do not leave piles of plant material or old soil next to your greenhouse. As much as these serve as habits inside the production space, they will do the exact same thing outside. No matter how well the inside is cleaned, if you have a major source of insects just steps away from the greenhouse...there will be problems
2. Collect all old growing supplies from the year, and remove from the space for cleaning. Pots, carrier trays, pruners, clips, support stakes/string etc. should be dealt with to reduce pathogen and pest load into the new production cycle. Pots, carrier trays and pruners can all be sterilized and re-used, but be aware of the cleaning agent used here - some are going to cause more harm than good! Wooden stakes, while tempting to re-use these, cannot properly be sterilized because they are highly porous. Disease transfer from year to year from re-using stakes is possible.
3. Consider swapping out ground cover! While this isn't something typically tackled on a yearly basis, following a heavy disease year it can be worth considering getting a new cover put over the ground. If you are considering this, remove the old cover before going forward with suds and sanitizer! That way your ground layer will be scrubbed back to a base layer of clean, and you can be confident that nothing is hiding out in tiny cracks and crevices throughout the old ground cover.
4. Suds up the space
• Giving all growing surfaces a soapy scrub is going to grab hold of any bacterial, viral and fungal agents that are still in the space and wash them away. 
• The best strategy for washing a greenhouse is to start at the top and work down - and this includes your ceiling! Failure to wash the top of the grow space creates a disease bank that can literally rain down on your future crop.
• Once you have applied your soap, give the production space a thorough rinse and allow it to air dry
5. Once you have allowed the space to airdry after cleaning, it is time to bring in the big guns- Sanitizer! There are a lot of sanitizers on the market to chose from, but they do have a few things in common:
• Contact time is important. Different products have different required contact times in order to be effective. Be sure to check what the required contact time is for your product of choice, and do your best to adhere by that. Otherwise there is no guarantee that the product will sterilize to the degree that you are hoping for
• Organic matter will de-activate sterilizing agents. Any of those leaves or soil bits that got left behind will actually render your product useless. 
• Consider how corrosive your cleaning agent is. Bleach is effective, but does impact the longevity of growing equipment, both for plastics and other materials.
• TEMPERATURE. Sanitizer efficacies significantly decrease at lower temperatures. While it is difficult to justify heating a protected space for cleanout, it is a key factor in maximizing your product efficacy.

Once sterilized, be conscious of what is coming into the space. Clean clothes/shoes/growing supplies should be the only thing that enter the space for as long as possible to maintain your clean growing slate.

Here's to a clean start!

Posted by: Talia Plaskett

Webinar Alert - Energy Alternatives in Protected Production

 Greenhouse Canada is hosting two free webinars on energy that are coming up soon!

Thurs May 5 at 3pm (Atlantic):  Biomass – Fire up the greenhouse

Biomass may be considered a renewable energy source, but where does it fit into Canada’s clean energy future for greenhouse agriculture? Learn about its use, the importance of fuel sources, as well as new developments that could give it a place on the journey towards net-zero emissions. Register here: https://us02web.zoom.us/webinar/register/WN_s8xsNXl7Rd-jNwiaB_tG0A

Wed. May 11 at 3pm (Atlantic): Reducing Carbon Emissions – Now and in the Future

What can greenhouse growers and vertical farming operations do to reduce their carbon emissions both now and over the next decade? This webinar will be centred around three main pillars: natural gas, demand-side management and low carbon solutions. Register here: https://us02web.zoom.us/webinar/register/WN_fVz9J78TS-WX5SlGY1E_aw

Each session will have a live Q&A, where you will have an opportunity to chat to the experts directly! Can't attend the event? Registering for the webinar will give you direct access to the recording afterwards, so it is worth putting your name in!

More info and registration can be found in the links above! See you there

Posted by: Talia Plaskett

Controlled Environment Agriculture Webinar Series

Making $en$e of Lighting During Propagation 

For the next episode in OMAFRA's webinar series on Controlled Environment Agriculture (CEA), Greenhouse Floriculture Specialist Chevonne Dayboll will be exploring the research that has been done with supplemental lighting during the propagation phase. 

Chevonne will be joined by two extension specialists out of Michigan State University, Dr. Roberto Lopez and Dr. Erik Runkle, to talk about their work on this topic, and help to point producers in the right direction when it comes to making decisions about supplemental lighting. 

Dr. Roberto Lopez is an Associate Professor and controlled environment/ floriculture extension specialist in the Department of Horticulture at Michigan State University. His research focuses on young specialty crop (floriculture, leafy greens, and herbs) propagation and finish plant production in greenhouses, growth rooms, and vertical farms. He earned his B.S. at the University of New Mexico and his M.S. and Ph.D. in Horticulture at Michigan State University. He has a research and extension appointment and teaches two courses: Greenhouse Structures and Management and Floriculture Production. 

Dr. Erik Runkle is a Professor and Extension Specialist in the Department of Horticulture at Michigan State University. He obtained a B.S. in Ornamental Horticulture from the University of Illinois and an M.S. and Ph.D. in Horticulture at Michigan State University. Since Erik joined the faculty in 2001, he and his graduate research team have performed numerous practical experiments in greenhouse and vertical farming environments to better understand how light, temperature, and other environmental factors control plant growth and development. Most recently, they have been focusing on how the photon spectrum regulates plant growth, flowering, yield, and quality attributes of horticultural crops, particularly ornamentals and leafy greens.

For more information on the event, or trouble shooting, click here!