I had to double check my calendar this morning to confirm that it's already March? That has to be the fastest February on record!
This month's newsletter is going to look a little bit different than our usual format. I have been quite busy conducting on-farm trials and demonstrations, so I wanted to give a rundown of some of the work that has been happening over the last few months/years. Some of these demonstrations are slotted to continue into the next fiscal (starting April 1) so it will be more background information than a summary of what we saw, but I still think there is value in letting you all in on the work that has been happening!
Instead of posting all of this information in one long newsletter, I'm going to post it in separate posts. That means we will have a few more notifications from me this month than normal, but bear with me! I'm hopeful that the shorter summaries will be much more digestible than pages and pages of information. As always, feel free to reach out if you want to learn more about the work that is going on, or if you have ideas for future trials and demonstrations!
Upcoming Events/Perennia Updates
Below is a summary of some of the industry events that are coming up in the next few weeks, and where you can find me! More information on the Perennia-hosted events can be found here.
- Tunneltalk Webinar Series
- March 3 - Irrigating Soil-based Crops in High Tunnels (pt 1)
- April 7 - Irrigating Soil-based Crops in High Tunnels (pt 2)
- May 4 - Enterprise Budget for High Tunnel Tomatoes
- Getting into the Weeds Webinar Series - Cost of Production
- March 3 - Tracking Cost of Production on Farm using "Compass" Tools
- featuring John Hendrickson, Farm Viability Specialist @ University Wisconsin-Madison
- March 18 - Horticulture Grower Cost of Production Panel
- panel to be announced
Recent Project Work: Nitrogen Application in Winter Spinach Demonstration - Funded by the On-Farm Climate Action Fund Program
The first demonstration that I'd like to talk about this month is funded by the On-Farm Climate Action Fund program. Before we get too deep into it I do want to post a disclaimer - this work serves as a demonstration only. It has not been replicated in Nova Scotia, and we are not conducting any statistical analysis on this. Pay attention to the rationale presented below as to what we did, why we did it, and what we expect...but the numbers generated represent one snapshot in time in one bed at one farm.
Under the nitrogen management umbrella, there were a few key messages I wanted to highlight when talking about the production of a classic winter green.
1 - The use of amendments in cold soils is not as straightforward as it is in the main growing season. The conversion of organic nitrogen into plant-available nitrogen is dependent on microbial activity. This process (called mineralization) is temperature and moisture dependent, which means when the temperatures are cold, there is little -to - no mineralization taking place. This has implications on the nitrogen sources that are being selected for winter production...meaning what works well for us during the summer months might not translate well into the off-season. Some of the things we want to consider when selecting nitrogen sources for winter production are the form of the amendment (pelletized versus a powder), how quickly it will break down (C:N ratios) as well as the amount of nitrate-nitrogen in our total nitrogen pool that will be immediately plant available for our fall plantings.
2 - Typically fertility is front-loaded for winter spinach production, however I want to showcase how a split application of nitrogen is going to impact yield.
Our demonstration was installed in September 2025. We worked out a treatment plan to include two different sources of feathermeal, two different forms of alfalfameal, bonemeal and bloodmeal. Our target amount of nitrogen for each treatment is 100 lbs/acre through the season, as recommended in the New England Vegetable production guides.
Each amendment was sent to the provincial analytical lab for mineral analysis - once we knew the nitrogen content, we weighed out the appropriate amount of each one, and spread it on the soil surface. Amendments were then gently ranked into the soil to help with incorporation. Due to the nature of the demonstration, a deeper incorporation would not have been possible without having the amendments mixed together.
Throughout the demonstration, we are collecting harvest information for each amendment type. We will also track information on plant nutrition through tissue tests, as well as soil tests with an additional nitrate nitrogen reading on them. Through this sampling regime, we anticipate being able to show how the different products are mineralizing over time, as well as what nutrients the plant is taking up.
While I anticipate the bulk of the differences between treatments are yet to come, here are some of the things we have observed so far:
Nitrate-nitrogen observed in the soil:
Our starting levels of nitrate in September soils was 26.85 ppm NO3-N.
This nitrogen is likely the residual left over from the summer crops. It bodes well for the germination of the next batch of plants, so that plant roots have access to some low levels of fertility to help get them going. From there, plants are reliant on the amendments that we have applied for immediate and long-term food sources.
This is where we are interested in the amount of plant-available nitrogen in relation to slow-release, organic nitrogen. If we are applying amendments with no plant-available nitrogen, then the plants are going to suffer until mineralization really gets going. For a winter crop, there could be some initial breakdown in the fall while the soils are still warm, but that will slow down and stop once temperatures drop. The majority of that mineralization would then start back up again as the greenhouse soils begin to warm up again (right about now) and into the spring and early summer crops.
If we chose an amendment that has some plant-available nitrogen right from the get-go, we can feel confident that we are feeding the plants adequately during a period of significant growth and transformation. Once the soil microbes have had the opportunity to mineralize the organic nitrogen, then the plants will start to see that nitrogen as it becomes available.
How has our soil nitrate changed through the winter?
We can see that depending on the amendment that was applied, there is a lot of variation in the nitrate nitrogen in the soil.
This tells me that the amendments are mineralizing at different rates. Plants that are treated with bonemeal in this case, are going to have more access to plant-available nitrogen compared to the other treatments.
Our next soil samples will be collected this week, so stay tuned to see what the lab is able to pick up here!
% Nitrogen Observed via Tissue Testing
Tissue testing is a great way to keep an eye on the nutrient status of the plant. To me, it serves as a proof of concept of what I thought was going to happen as a result of my amendment application schedule - I've applied X of this amendment, is the plant actually accessing that nutrient? Or is something getting lost in the mix...We submitted a tissue test to the provincial lab in November and December. A few things we can see happening here:
1) we have higher nitrogen observed in December (orange) than we do in November.
2) the levels do not differ significantly depending on the amendment that was applied
Yield
We wouldn't be able to fairly assess the different fertility regimes without looking at yield. I've organized the data in two different ways for you here:
1) Total yield. This is comprised of the average yield for each amendment for the first and second harvest, then added together. We have some clear differences in the yield observed between our different treatments.
2) Average yield per harvest. This is what we saw within each amendment for our November harvest and our December harvest. We noticed a significant drop off in the amount of material we were harvesting, which makes sense with light levels this time of year.
We can also see that there are significant differences between the amount of spinach harvested and the amendments used. Interestingly those trends are not consistent between the two harvest dates - while bloodmeal and alfalfa meal were amongst the lower harvests in December, those plants performed much better than some of the others for our first spinach harvest in November.
I'm not going to spend much time speculating on why this may be, but will say I am very curious to see what our March harvest will show us!
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Hopefully you enjoyed this high level summary of our winter spinach work so far, and I look forward to continue sharing information on this as it comes to light.
Happy growing everyone!
Talia (tplaskett@perennia.ca)
