Upcoming Events/Perennia Updates
Below is a summary of some of the industry events that are coming up in the next few weeks! The events listed below are primarily hosted by Perennia, and more information on each of them can be found here.
- UNH High Tunnel Production Conference
- December 10,11 - West Lebanon, New Hampshire
- More Information to be Found Here
- Tunneltalk Webinar Series
- December 15 - A review of Quebec Berry Production
- January 12 - Soil Testing and Fertilization for in-ground Tunnel Vegetable Production ft Vern Grubinger from UVM
- February 23 - On-Farm Adoption of IPM Strategies
- Nitrogen Management Workshops - Focus on Amendments
- January 13 - Middleton
- January 21 - Antigonish
- January 22 - Stewiacke
- Horticulture Nova Scotia Congress
- Old Orchard Inn, January 26, 27
Seasonal Considerations - Interpreting a Soil Analysis
As things wind down, and we start to consider what our crop plan looks like for 2026, we cannot forget about our fertility plans as well! This is a great time of year to be grabbing our soil tests if you haven't already. High tunnel soils should be tested every year, as a result of the intensity that we tend to crop that space, and how significantly those spaces can change in very short periods of time.
Samples can be submitted to the provincial analytical lab, whose website can be found here. There are instructions online on how to take the soil test, as well as the process for getting it submitted. Samples can be dropped at your regional office, who will see to it that it is transported up to Truro. Be sure to call ahead though, samples are only moved once a week.
Unless you are submitting potting mix or substrate, you want to select the S1 package for a mineral soil analysis! We will chat with Vern Grubinger from UVM in January about how we can use a saturated media extract (SME) for our fertility planning in greenhouse soils, but until then...let's stick to our traditional mineral route.
For those of you who haven't submitted yet, here are a couple considerations:
- submit a sample from each greenhouse space
- If you have multiple greenhouses, I would recommend sending individual samples for each individual tunnel. You would be surprised by the amount of variation across the spaces!
- select the crop you are planning to grow when submitting your soil test
- This will help the provincial lab generate N-P-K recommendations, making it that much easier to put your plan together
- If you have noticed that one particular corner or area of the greenhouse has shown crops with nutritional deficiency, submit that spot separately if you want to try and address it
- We can spot-treat different parts of the greenhouse within reason, and hopefully even out production across the high tunnel as a result
- Try to prioritize the soil that is most representative for the space
- Try and avoid pulling and bulking samples from low/wet spots in the space...these may not be the best for making decisions about your greenhouse as a whole
Here are some of the things I look at when interpreting a soil analysis for a high tunnel space:
pH -
On our NS soil test, we are looking at the pH value recorded, NOT the buffer pH.
Nutrient availability is highly dependent on the pH of your growing media. The target pH you are aiming for will depend on your growing media, and your target crop of course.
- soils = 6.5
- peat/coco substrate = 5-5.8
Typically high tunnel soils have very high pH numbers, resulting from year after year bulk applications of compost. Unfortunately reducing soil pH is not nearly as easy as increasing soil pH, but there are some options we can discuss if you find yourself in this position!
Organic Matter (OM) -
Soil organic matter is great in many ways. One of the more recent ways that we can use our reported %OM is to turn that value into an estimate of nitrogen release.
A&L Lab's put together a blog post recently that outlined the calculation that can be used to transition our reported % organic matter, into an estimation of nitrogen release in that year. Of course, these releases are dependent on the composition of that organic matter, the amount of moisture in the soil, and environmental conditions. To me, that means that we wouldn't expect as much nitrogen released in winter crops as the calculation implies, and the soils should be supplemented accordingly so that we don't see loss of yield.
Some additional conditions that would slow the mineralization of nitrogen, thus resulting less per year than the calculation cranks out:
- High levels of organic matter (>20%) will see slower breakdown
- Highly saturated soils for a portion of the year will also see slower breakdown
- Artificially drained soils may see faster breakdown compared to those that do not
From the post: If we assume that organic matter is 5% nitrogen by weight, with a reported value of 3% organic matter, and an anticipated release of 2-4% plant-available nitrogen in a given year:
- We can anticipate 60-120 lbs of available N per acre
I encourage you to check out the article on your own time, and maybe plug in a few numbers of your own!
Phosphorus (P) -
We want to be looking at the P205 value on our soil report - this represents the 'fertilizer value' of phosphorus. The total value listed on this report, however, is not completely plant available.
Typically this number is quite high in high tunnel soils, and despite not being completely plant available, I hesitate to suggest large inputs of phosphorus to try and manage the build-up over time.
Through various sources I've heard that buckwheat is a good cover crop to grow to try and deplete soil phosphorus levels, and the following abstract says as much. Of the 5 species they tested in this study, maize and buckwheat were the most effective at reducing soil P in medium - to - high phosphorus soils. Triticale removed less P than buckwheat, maize, and sunflower at every soil phosphorus level.
This would be a really cool demonstration to showcase, so if anyone gives this a go I would love to hear the results!
Calcium (Ca) -
While calcium is an essential plant nutrient, we tend to see it accumulate in high tunnel soils. It is typically an accessory to some compost and manures, and can significantly outweigh the amount of other beneficial nutrients that are added through these mediums.
Calcium has a stronger claim to our soil particles than both magnesium and potassium. What that means, is that in a scenario where we have excess calcium in our soils, we may see signs of magnesium and potassium deficiency, even if our soil test tells us we have excessive levels magnesium and potassium.
While I don't have a great calcium-specific solution to accumulation in high tunnel soils, careful selection of our amendments is a great way to make sure we aren't making the problem worse.
If you see that you have excess calcium in your soils I would make a plan to supplement magnesium and potassium in-season. It's an added assurance that the crop has access to the essential nutrients it needs in order to put out that beautiful produce we all dream about.
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While this is just a quick summary of the information we can glean from a mineral analysis of our soils, I hope that it helps when it comes to your planning for next season! As always, I'm happy to take a look at your results and provide some feedback.
A Few Note-Worthy Uploads:
That's all for now! I hope you are gearing up for a restful holiday season with loved ones.
Happy growing everyone!
Talia (tplaskett@perennia.ca)
