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!

Things to Consider When Selecting Soilless Substrates

Soilless substrates are used across the world, offering a solution to those with difficult soils to grow on, or those who are looking to increase efficiencies when it comes to nutrient and water inputs. These substrates are comprised of non-soil components, but still provide the structural support needed by the plant in order to grow.

When it comes to the base material used for soilless grow media, there are two groups: synthetic and non-synthetic products. 

How do I chose what substrate to use?

While both synthetic and non-synthetic substrates are good options for providing structural support, nutrients and water to the plant root system through the cropping cycle, there are a few key questions to consider when purchasing a growing media:

1) What is the cost? 

Substrates are not created equally when it comes to cost. It is not recommended, however to chose the cheapest/most expensive one without understanding what you are getting with it. It is definitely an important factor to consider, but make sure that you understand the rest of the list below when making your choice. 

2) Where is the material coming from?

In COVID times, shipping delays are all too real for producers of all shapes and sizes. This should definitely be a consideration if you have yet to order your growing media for the upcoming season. There are many local substrate providers who might be able to fill your needs without having to ship overseas. 

3) What is the baseline nutritional status of the media?

While soilless substrates do not have much to offer in terms of baseline nutrients, it is important to realize that there are differences between the base materials. Some substrates are going to be more prone to having high initial salt levels compared to others, and if the media is not treated properly, these salts can be very damaging to your new crop. Be sure to ask your provider about your substrate and the treatments it has received. 

4) What is the particle density, porosity and particle size range of my substrate? 

These are key parameters that are going to determine how well or how poorly your substrate holds on to water. A substrate with tiny particles, means that the air and water spaces within your media are also going to be very small. This makes it harder for the plant to pull water out of those air spaces. It is also difficult for this water to drain out of the media, meaning the roots are more prone to sit in a wet matrix, regardless of the time of day. This has a tendency to lead to root disease and sub-optimal plant productivity. On the other end of that spectrum, large particles have very little capacity to hold onto water, meaning you are significantly increasing the number of irrigation events throughout the day to sustain plant growth. 

5) How do I want to handle my substrate?

Substrate is available for purchase in a few different forms. It can be purchased in large bulk orders, where the producer must hydrate, divide up into the individual growing containers, and then move those containers into the growing space. The other option is to purchase pre-filled slabs (also referred to as grow bags). Some crops have the option for specialized containers that help mitigate some production issues that typically develop down the line, while others don't. It is up to the producer, the target crop, and the labour force available, to decide which method is going to work best for that particular operation. 

6) What am I going to do with my substrate now that I'm finished with it?

This is where things get a little hairy. Synthetic substrates cannot be composted, and usually require transport off site for disposal. Non-synthetic substrates do have the option for composting, but must be done in a strategic way to prevent the accidental creation of an oasis for lingering insects and disease. This plays in to point number 5 as well - removing the inner contents of a slab wrapped in plastic is much more time consuming to compost compared to a crop grown in a container.   

_________________________________________________________________________

For those who are new to growing in substrate, these questions can be overwhelming...but never fear! Your Protected Crop Specialist is here. If you have any questions on soilless substrates check out some of Perennia's resources:

• 2020 - 2021 Getting Into the Weeds Session on Soilless Substrate
• Perennia's fact sheet on Substrate
• Contact Talia Plaskett, our Protected Crop Specialist

Controlled Environment Agriculture Webinar Series

 Dr. Fadi Al-Daoud, OMAFRA's Greenhouse Vegetable Specialist, will be hosting a webinar series focused on Controlled Environment Agriculture (CEA). This will cover information relevant to all  protected crops, including berries, vegetables and floriculture. 

Join Fadi, and his guest speaker Peter Kamp, in the first installment of this webinar series on January 20, 2022 at 1 pm AST. Peter will be discussing a new crop steering principle which hinge on the basis of overall water balance within a plant. 

For those of you who are not familiar with the concept of plant steering, it operates on the basis of manipulating environmental factors to encourage vegetative or generative growth. Both vegetative and generative growth are important for establishing a healthy crop, but it is important that the timing of these two stages happens at specific time points during the cropping cycle. There are a handful of ways  we can push a crop towards increasingly vegetative growth, or increasingly generative growth, and this webinar looks to discuss a new tool to be added to our steering toolbox. For more information on crop steering, check out three of our previous posts titled 'Creating a Balance'. Each has been tagged with the tagline 'vegetative' and 'generative', so scroll through our tag list on the right side of your screen to take a look!

For anyone interested in registering for the session, click here for the link. 

Hope you there!

Posted by: Talia Plaskett

Whats New with Biological Control?

  2021 has seen a lot of new and exciting things in the world of IPM with some of the tools available to producers for managing pest populations. Please find a quick summary of some of these new developments below with their corresponding contact information – this is a list of curated material from various sources, credit must be given where credit is due!

1)Introducing Anystis, the new generalist predator in our toolbox

 Anystis is a new generalist predator which was discovered and trialed by Vineland Research and Innovation Centre. This predator has shown control over thrips and spider mites as well as suppression of aphid populations. Not only that, but it also preys on Echinothrips and mealybugs, which currently do not have effective options when it comes to biological control agents! Not only that, but Anystis is compatible with other commonly used biocontrol agents, meaning less stress about adjusting your current regimes and more success overall when it comes to targeting your problematic pests. 

The use of Anystis has been validated in commercial greenhouse trials on gerbera and sweet pepper in Ontario, and further supported by promising results generated through recent trials at Niagara College for use in cannabis to control aphids. The predator has been transferred to Applied Bio-nomics Ltd for scaling up the rearing system and commercialization, and have a limited number of mites available for growers to try.

For more information on Anystis, contact Rose Buitenhuis, PhD Senior Research Scientist, Biological Control at Vineland Research.

 

2)Slow-release method of nematodes

The current application of beneficial nematodes is limited to sprenches, or drenches, across the surface of the growing media. The biggest targets for beneficial nematodes are the larvae of fungus gnats and western flower thrips, as well as onion thrips pupae. While the product is quite effective, the current application method to the crop sees a few technical difficulties. These drenches/sprenches are not the most effective when it comes to penetrating deeper into the growing mix, and they must be applied on a weekly basis. Not only that, but the current methods of distribution sees a very poor storage capacity – all must be distributed at once, which leaves the small producers in a bit of a financial pinch!

E-Nema is a new tech company based in Germany. They have come out with a slow-release method for these beneficial nematodes which tackles some of the difficulties associated with the existing system. These look similar to tapioca pearls, and are designed to be incorporated into the growing mix before planting. Then, over time, they will slowly release nematodes through the entirety of your growing container. These pearls are very safe, and do not contain any harmful chemicals. In addition to that, they store quite well, which is a win for smaller producers who may not need massive volumes to be distributed all at once. The reintroduction and inoculation of low doses of nematodes has proven to be more effective than coming in hot and heavy with one dose during the cycle, and this technology allows just that! 

BioBee will be the distributer for this new product, so be sure to keep your eyes peeled for that! I want to give a huge shoutout to the Cannabis Cultivation & Science Podcast for keeping up with the biocontrol world and spreading the word on cool innovations like this one!

3)New rearing methodology for Phytoseiulus persimilus

Our old reliable predatory mite is coming at us new and improved! BioBee has re-evaluated their current rearing methods for persimilis and has landed on a product that addresses some of the downfalls to the original release system. The original system sees that the predators are reared on spider mites, meaning they come out of their sachets starved and ready to tackle some serious spider mites. While that works well in heavily infested crops, it doesn’t bode well for the low pest pressure grow room, or the preventative release strategy either. This new product raises the predators on mite eggs, meaning that each sachet will come with a variety of life stages, and each sachet will have a long-life span overall as these different stages progress towards adulthood. These sachets can see up to 12 days to release the contents, giving you almost 2 weeks of release from one purchase. The new food source sees that these mites are not as hungry as they would be when raised on spider mites. This means they have time to establish in the crop, as well as hunt down those low density mites that are scattered through the room. Not only that, but there is no carrier mixed in with these predators. This is a huge win for producers of heavily-trichomed crops, as their plants will no longer be littered with pesky lingering carrier bits.

Figure 1. An image of persimilis predating on a two-spotted spider mite. Photo credit: Biotactics Inc. 

This new persimilis can also be purchased in bottle form. But grower be warned! It was interestingly noted that these predators are not their characteristic red colour when you receive them from the insectary. That colour develops on the persimilis as they start feeding on spider mites. This acts as an added bonus when it comes to your scouting efforts. If you note which predators have transitioned from milky to red, you can get a sense of the pest pressure in the space and how effective your release was at managing the spider mite population.

I want to give a huge shoutout to the Cannabis Cultivation & Science Podcast for keeping up with the biocontrol world and spreading the word on cool innovations like this one!

______________________________________________________________

Posted by: Talia Plaskett

Out With the Old, In With the New!

 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.

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. 
3. 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
4. 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

Creating a Balance : Vegetative vs Generative Growth

Part 2 - It's All in Your Water

There are many factors that play a role in managing vegetative and generative growth, and it is important to consider a well-rounded approach when attempting to swing the scales. Keeping a balanced growing environment is important for a highly productive plant and changing one thing and nothing else will end up causing more harm than good.

In part 1 of this mini-series, we addressed the need for vegetative growth to have a high yielding crop. Vegetative action is required early in the crop cycle so the plants can establish themselves. By creating this strong base, the plant will be able to support a highly productive generative state later on.

The generative growth phase focuses on managing plant productivity. It is achieved through strategic stress induction in your plants. These minor stresses are going to push the plant to divert resources to reproductive organs (fruits), while ensuring that all other plant processes can be maintained. The key word here is minor – pushing the plant too far is not going to have the response you are looking for.

How Do I Manipulate the Plant?

A few of the major contributing factors to vegetative and generative growth are listed here below. We will address the impact that each factor has on crop steering.

•        Water availability
•        EC
•        Day/Night temperatures
•        Vapour Pressure Deficit (VPD)
•        Pruning
•        Fruit load

Water Availability

Watering frequency, duration and timing plays a role in pushing the plant towards a more vegetative or generative state.

In vegetative action, water is readily available for the plant when it needs it. The plant does not have to work hard to uptake water and will readily create new above- and below-ground biomass. As roots and leaves are being produced, the plant is preparing for full-blown production. Higher water content in the substrate is achieved through small, frequent irrigation events throughout the day.

Once it is time to switch to generative growth, these watering events become longer and more infrequent. As water becomes less available, less energy is put towards the production of root and shoot material, and more will be diverted to fruit production. The plant will now have to actively seek water compared to it being readily available in the vegetative stage.

Figure 1. Depicted here is the general irrigation strategy for substrate-grown greenhouse crops (ex. Tomato). Water content (WC) is depicted in green. While the timing and frequency of watering for generative and vegetative phases will vary, the general concept applies. As the day ramps up, you slowly increase the amount of water you deliver to the crop. After you achieve first run-off, you can start hitting the crop with water at regular intervals (determined, in part, by the weather that day). As the end of the day approaches, irrigation stops all together. Photo credit: Greenhouse Canada, June 2010 (https://www.greenhousecanada.com/september-2010-2418/)

While the daytime irrigation strategy is important in crop steering, you must also consider what is happening through the night. The length of the dry-down period of your growing media will help to tip the scales towards vegetative or generative tendencies. A short dry-down period (usually achieved by scheduling the last irrigation event of the day 1-2 hours before sunset) encourages vegetative growth. A longer dry-down period (which would have the last irrigation event happening earlier in the day) will encourage generative tendencies.

EC Measurement

The electrical conductivity (EC) of your fertilizer solution is important to consider when encouraging vegetative or generative action. EC is an indication of the salt content in the solution and will therefore impact water availability to the plant. A higher EC value means a higher salt content, and the harder the plant must work to take up water. As the plant works harder to take up water, less resources will be sent to vegetative growth (leaves, roots) and more will be sent to the generative tissue.

Here is a rough guideline of where your target EC should be, based on the crop stage:

Plant Stage	Target EC
Germination (vegetative)	0 - 1
Plant raising (vegetative)	2.5 – 3
Harvesting (generative)	2.75 – 3.5*
Full harvest (generative)	2.75 – 4*

*Should be watering with an EC of around 3, but you will see a higher substrate EC as the salts accumulate in the grow media

Understanding how your watering habits sway the crop in one direction or the other is a good starting point. Irrigation is something that all protected producers have control over, and it is important to see that watering plays a huge role in plant phenology and overall production capacity.

Creating a system that encourages maximum production capacity is in everyone’s best interest, and it is extremely important that all factors are addressed when trying to push for a more generative crop. Adjusting the watering and EC alone are not going to be enough to hit the target yield. All plant processes are intertwined and should be carefully considered whenever adjustments are made.

Stay tuned for our next post on vegetative vs generative growth, which looks at the role of temperature and humidity in crop steering.

Posted by: Talia Plaskett