Field Observations

April 30, 2026

Planting has begun on limited acres across the province so far this spring. Winter wheat continues to grow, but there have been some challenges in getting products applied.

Corn

As the potential for warmer weather approaches, the big question on many growers’ minds is: When should I begin planting?

A key to establishing the crop’s potential is planting it into a seedbed that can provide even and timely emergence. Most importantly, the soil needs to be fit (not too wet, not compacted or lumpy) before planting for ideal emergence. Planting into soil that is too wet can create sidewall compaction, limiting seedling root growth.

The ideal soil temperature for planting corn is 10 C or above to achieve uniform germination and reduce seedling stress, which can result in corkscrewing and leafing out under the surface. When placed in the soil, the seed will absorb about 30 per cent of its weight in water. The temperature does not affect water imbibition much. However, this differs from radicle (root) and coleoptile (shoot) growth, whose growth is correlated with soil temperature.

In cold soil conditions (below 10 C), seeds will readily absorb water but not initiate root or shoot growth, leading to seed rots and poor emergence. Recommendations are to begin planting when soil is near 10 C, or the forecast is favourable and trending warm. Some growers have experienced cold conditions after planting the last few years, and colder fields, such as no-till fields, experienced lower emergence populations due to cold stress, resulting in leafing out underground. Techniques to warm the soil or waiting until soils warm up will help with better stand establishment and uniformity. Being aware of soil fitness and temperature helps ensure plants will be off to a good start.

When the planter does get rolling, aim to maintain a planting depth of two inches into adequate moisture to ensure uniform germination.

Soybeans

As with corn, it is imperative to plant soybeans into fit soil. It is also crucial to know soybean seed germination. As soybean planting edges closer and farmers are finalizing planting plans, something to consider is the final plant stand goals, and what planting population is needed to achieve that. Seed germination is one part of the calculation, as are planting conditions and weather conditions after planting.

Due to drought conditions in several regions of Ontario, some soybean seed this spring may not germinate at the same rate as in previous years. It would be wise to know the germination rate before planting, so seeding rates can be adjusted. For example, if a 150,000 plant stand is desired, the planter will need to drop 187,500 if the germination rate is 80 per cent. Also, adjust the rate based on seedbed conditions, or if there are other concerns about emergence, such as crusting, etc.

Seed tagged with a Canada Certified No. 1 seed tag will have an 85 per cent germination rate or greater. Canada Certified No. 2 seed will have 75 per cent germination or greater.

Note: Some companies may have greater internal tolerances, which is used to determine which seed lots to sell. Of course, everyone wants to sell the best quality, but conditions in the previous year may affect germination rates in different seed lots. A seed germination test is the best way of knowing, so asking about your seed provider’s germination rate or getting a test done before planting will provide you with the knowledge needed to adjust seeding rates.

Schedule 1 to the Seeds Regulations Grade Table 5 for Soybeans and Corn https://csi-ics.com/sites/default/files/seed_regulations_grade_tables.pdf .

When planting does begin, aim for ideal soil conditions to get the crop off to the best start. Ideal planting depth is one to 1.5 inches, unless reaching soil moisture is critical later in the season, where 2.5 inches is possible. However, the deeper the seed is planted, the higher the chance that the soybean hypocotyl runs out of growth with the cotyledons not being able to reach the soil surface, causing poor emergence.

Cereals

Winter wheat is rapidly advancing with the warm weather, staging at GS 25 to GS 32. For some, wheat is at or near the second application of nitrogen, along with a herbicide, a T1 fungicide, and, if warranted, a PGR (plant growth regulator).As wheat plants approach growth stage 30 (stem elongation), it is the last stage at which some herbicides can be used without risk of injury. By GS 30, the number of spikelets per head has been determined.

GS 31-37 can be very challenging stages to identify. Use a knife to split the main stem and count the number of nodes separated by the internode. GS 31 will have one node detectable, the first node detectable must be above an internode of at least one cm, while the second and so on nodes detectable must be above an internode of at least two cm.

While some winter wheat acres have received a nitrogen application, there have been challenges of getting nitrogen and other products applied due to wet soil conditions (which could cause compaction on waterlogged soils) or windy conditions.

Looking at the long-range forecast for parts of the province, temperatures are still on the cooler side, especially at night, dipping down in some areas to below 0 C. If application is occurring, especially if mixing multiple products in a tank mix, remember to watch temperatures (before, the day of, and after application, aiming for above 3 C the day before, the day of, and the day after) and read labels to ensure that you are using the appropriate tank mix partners.

Several years ago, there was a cool, late spring that brought about many questions on how to prioritize trips across the field. More can be found here in this Field Crop News article.

Soil sampling and 4Rs

Planting new ground or fields with unknown fertility levels? A best practice is to ensure that a soil sample has been completed in order to have a base line knowledge of fertility levels. Soil sampling allows nutrient applications to be made following the 4R principles: Right source, Right rate, Right time, and in the Right place. 

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April 22, 2026

Although an early spring was predicted by Ontario’s resident groundhog, it has been slow to arrive, with some areas of the province receiving snow this past weekend. We recently asked the OMAFA crop specialists what farmers should consider as spring approaches with respect to planting date and fertilizer.

Corn

Ben Rosser, corn specialist with OMAFA, said: “Given the year and fertilizer prices, having a recent soil test will help to make more informed fertility decisions.”

He said that for very low soil-test results, even expensive fertilizer can still provide a good return on investment. With non-responsive soil-test results, it may be possible to reduce or skip applications if you expect future years will have more favourable fertilizer-to-corn price ratios.

“Use the Ontario Corn Nitrogen Calculator to see how different fertilizer and corn price ratios affect nitrogen fertility recommendations. For example, at today’s price ratios (nitrogen being more expensive relative to corn), the most economic N recommendations might be about 10 per cent lower than what a 10-year average might have been before N fertilizer prices started to run up before 2022.”

In the field, he said: “Use test strips to evaluate N needs on the farm. Can rates be pulled back without any yield loss? Is there yield being left on the table in very high-yielding years? Collecting yield-response data is the only real way to know.”

“An easy, low-risk way would be to do some 30-lb. test strips (a strip 30 lb.-N/ac. more and 30 lb.-N/ac. less than grower practice, then check yields for all three rates in the fall). Also consider how much yield you expect.  Doing a zero-N strip can provide insight into how many bushels you are getting from soil-N supply and how much yield you are trying to gain with N fertilizer. In some Thames Valley Soil and Crop Improvement Association trials, starter-only N (about 30-40 lb.-N/ac.) yields about 60 per cent of N-rich, but this can be highly variable across fields.”

He added: “We talk a lot about the importance of uniform emergence and growth in corn, and that starts at planting.”

“There has been more talk recently about the importance of tracking, or benchmarking, stands. Most growers know their seed drop, but what is the plant stand, and how many ear-bearing plants are still there at harvest? Those are good numbers to know and can help troubleshoot or identify areas to improve in future planting seasons.” The Ontario Corn Agronomy Network, a pilot program in 2026, is focused on helping farmers hone agronomic decisions and benchmark against other fields to identify potential improvements. Registration for 2027 will open early next year.

On planting date, Rosser said Dave Hooker, Horst Bohner and Seth Ritsma recently completed Grain Farmers of Ontario-funded planting-date trials for corn and soybeans. “While timely planting is always important for both crops, the data showed that economic responses for corn planting dates (corn yield minus drying costs and downgrades) are fairly flat for the first half of May and start to decline more quickly after about May 20.”

Rosser added: “Sometimes it seems that once the calendar switches to May 1, there is a feeling we are losing yield or income by the day we are not planted. But the data does not necessarily bear this out. There can also be season-long costs from pushing planting conditions: compaction, non-uniform emergence or uneven stands. Balance the calendar date with field conditions and the expected number of days needed to finish planting for season-long success.”

As spring approaches, some corn fields still need to be harvested from last fall, with standability challenges in some cases. Fields harvested this spring may create volunteer corn issues in the 2026 crop. Build a herbicide plan that considers that risk.

Soybeans

We also asked Horst Bohner, soybean specialist with OMAFA, to share his thoughts as planting approaches. He said planting date is “an important management tool to maximize yield potential. Generally, early planted soybeans (late April to early May) yield more than soybeans planted in late May. Early planting allows for more nodes per plant, and therefore more pods. June-planted soybeans yield the least.”

He added: “Soybean planting should be based on seedbed conditions, the weather forecast for the 48 hours after planting and, to some extent, the calendar. Since soybeans will be destroyed by a killing frost once they have emerged, ultra-early planting (before April 15) is problematic in Ontario. Plant stands are also a consideration when planting early.”

Bohner said that if weather delays planting, there is good news when it comes to soybeans. “Since the majority of yield is ‘made’ in July and August, late-planted fields can do very well if the remainder of the growing season is good. Since soybeans adapt (within reason) to the growing season because they are daylength-sensitive, it is not necessary to switch varieties unless planting is delayed until late June or July.”

“If farmers are considering switching, the main purpose of moving to an earlier maturity group is to ensure the beans can finish before a killing frost in the fall. Since late-planted fields result in shorter plants that do not branch as much, it’s a good idea to increase the seeding rate to maximize yield potential.”

Bohner said lower plant stands are common with early planting since soils are cooler. “It is critical to have a good seedbed. Soybeans should always be planted into fit soils, regardless of planting date. If significant rainfall is forecast, wait until conditions improve before planting. A cold rain immediately after seeding will affect emergence.”

“Yield response to planting date will vary depending on the growing season and the maturity group of the variety. The key to getting the highest yield possible when planting early is to select a variety that is full-season for a given area. Planting a short-season variety early does not consistently increase yields compared with a more normal planting window.”

Bohner also noted that the importance of soil fertility for high-yielding soybeans is sometimes overlooked. “High-yielding soybeans require large amounts of nutrients. If the soil test is ‘good,’ then the job is done. Additional fertilizer will not add to yield. But for many Ontario fields, soil tests for P and K are insufficient to maximize yields.”

Spring cereals

Joanna Follings, OMAFA cereals crop specialist shares her thoughts. “The earlier we can get spring cereals seeded, the better. Research has shown that frost seeding or seeding spring cereals early helps avoid those hot and dry growing conditions during the grain fill period. Spring cereals do well when temperatures are cool, especially during the initial growth stages. We often see an increase in tillering and can also avoid some of the early season diseases.

“Even in a year like 2020 where we saw snow in parts of the province in May, the early seeded cereal crop was small enough that the temporary cold temperatures had little impact on the small cereals. Once they get to the stem elongation phase and the growing point has started moving up the stem it is more prone to cold injury; however, we don’t often run into temperatures that are too cold for spring cereals.”

Follings adds, “If seeding of spring cereals is delayed, growers should bump up their seeding rates. When spring cereals are planted late, temperatures are often higher, and the growth and development of the crop is much quicker in higher temperatures. As a result, we see the crop will often have a lower yield potential. By bumping up the seeding rate, we can help compensate for the reduced tillering and potentially lower test weights due to warm temperatures during the grain fill period. Growers should also ensure the variety they are growing has a good disease package. Later planted fields tend to be more susceptible to diseases – specifically crown rust in oats and FHB in spring wheat.”

Winter wheat

There are some very lush wheat fields in the province, having been planted early, with good tillering. Fields that had two tillers in the fall are now seeing seven to eight tillers, with some fields in southwestern Ontario at growth stage 31 (stem elongation). The start of stem elongation is an important time for weed control, nitrogen applications and the start of the optimum window for most PGR applications. This is also the last stage when some herbicides can be used without risk of injury. Always read and follow labels, choosing the appropriate herbicide for plant stage.

 If fields are more delayed, but have an even plant stand, they still have a good yield potential. If you’re worried that plant stands are not where they should be with fields greening up, review this plant stand chart to estimate potential.

If it was planned that wheat was going to get two applications of Nitrogen (N), some of the winter wheat acreage has received the first application. Wet fields have hampered application across much of the province.

Sulphur (S) is a required nutrient for plant growth. With less sulphur being deposited from the atmosphere, crops have been showing more deficiencies over the years. If you are not using sulphur and need to show its value, one of the best ways is to do a split field or test strips. Typically, lower organic matter and sandy soils see a higher response, but crop response has been measured on all soil types. The recommendation from OMAFA for winter wheat is 10 lb./ac. of S. It is important to note that the higher the N rate, the higher the S rate should be. Ratios of 10:1 to 8:1 are a good guideline, but adjust based on local needs. Ontario research has shown variation in yield responses to S depending on the year; cool, damp springs have shown more of a yield response.

Grain Farmers of Ontario is currently investing in further sulphur rate research with John Lauzon at the University of Guelph.

Slugs

Slug feeding can cause damage during crop establishment and early growth, resulting in poor plant establishment and replanting in some situations, and potential yield loss. Learn more about slug identification, favourable conditions and control in this Grain Farmers of Ontario factsheet.

Mental health

As the spring rush approaches, please keep your mental health in mind and reach out for support if needed.

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April 16, 2026

A cool, wet, and in some cases, snowy spring has so far delayed many field operations.

Wheat

Scouting whether to keep or terminate a wheat field has been ongoing in various areas. Some fields are looking quite good, while others are struggling due to late planting, heavy rains after planting, and, in some cases, snow mould. A quick lesson on assessing wheat stands can be found here .

Fields planted early last fall tillered nicely before winter and are well established this spring. These fields do not necessarily need an early application, but can benefit from an N application as the season progresses. The best timing is before the plants start to stem elongate; however, keep in mind that application timing can be affected by when fields are dry enough to carry the equipment without causing field damage (rutting). It’s important to check the weather forecast and walk the fields to check the growth stage of the crop.

A delay in N application can result in the crop showing signs of deficiency. The yellowing of wheat due to a lack of N in the soil is a sign of crop stress. Early stress on the crop will cause fewer florets to develop, which means fewer kernels, and a lower yield.

It’s also important to note that a herbicide application needs to occur before stem elongation to prevent damage to the plant and head development. Any stress just before, and during, stem elongation can cause damage to the developing head and reduce yield potential. Scout early, and scout often for plant growth, weeds, and diseases.

Following your wheat crop along, and timing crop protection and nutrient applications is important for optimizing yield. The visual guide to winter wheat staging is a handy tool for identifying what growth stage your crop is at!

Insects

As we approach planting, insect pests should be monitored as they may affect crop stands. In some cases, the insect larvae can cause significant reductions in stands and early season plant vigour. High-risk fields are those that are being planted early, following hay or grass, fallow, or a grassy cover crop. If the spring continues cool and wet, it will be favourable to early season pests. Learn more here. 

Weeds

We recently received some insight from Mike Cowbrough, OMAFA’s weeds specialist, about the weed spectrum in Ontario, and what growers should be aware of.  

Cowbrough shared, “Both the number of herbicide-resistant weed species in Ontario and the number of herbicide groups to which those weeds are resistant continue to increase over time. This is almost inevitable, as intensive and repeated use of the same herbicide modes of action increases the likelihood that weed populations will evolve resistance.

“Additionally, the introduction of new weed species from other regions that already carry herbicide resistance, such as Palmer amaranth, is something we have seen recently in Ontario. In some cases, crops used as cover crops become problematic weeds themselves, for example, Italian ryegrass, which is widely used as a cover crop, turfgrass species or forage grass species, now has confirmed glyphosate-resistant (Group 9) populations in Ontario, making it much more difficult to control.”

Fields planted early last fall tillered nicely before winter and are well established this spring. These fields do not necessarily need an early application, but can benefit from an N application as the season progresses. The best timing is before the plants start to stem elongate; however, keep in mind that application timing can be affected by when fields are dry enough to carry the equipment without causing field damage (rutting). It’s important to check the weather forecast and walk the fields to check the growth stage of the crop.

A delay in N application can result in the crop showing signs of deficiency. The yellowing of wheat due to a lack of N in the soil is a sign of crop stress. Early stress on the crop will cause fewer florets to develop, which means fewer kernels and a lower yield.

It’s also important to note that some herbicide application need to occur before stem elongation to prevent damage to the plant and head development. Always read and follow herbicide labels. Any stress just before and during stem elongation can cause damage to the developing head and reduce yield potential. Scout early and scout often for plant growth, weeds, and diseases.

Following your wheat crop along and timing crop protection and nutrient applications is important for optimizing yield. The visual guide to winter wheat staging  is a handy tool for identifying what growth stage your crop is at!

Mike was also asked if there are any trends of particular significance for Grain Farmers of Ontario and relayed the following:

1) The increased prevalence of group 14 resistant weeds – pigweed, waterhemp and common ragweed

2) Increase in prevalence of glyphosate resistant ryegrass

Weeds resistant to multiple herbicide modes of action are increasingly common, and this is especially concerning since there are not many options available to manage such species.

Multiple-herbicide-resistant waterhemp is the clearest example. In Ontario, waterhemp populations have evolved resistance to five herbicide groups (2, 5, 9, 14 and 27), and herbicide-resistant waterhemp has been confirmed in 19 counties from Southern Ontario to Northern Regions.  Multiple resistance is also very common in other key species relevant to growers and their rotations, including common ragweed, green and redroot pigweed, and Canada fleabane.

Palmer amaranth is not yet widely established in Ontario, but it is widespread in field and vegetable crops in the United States and is associated with severe yield losses. Our recent work has detected Palmer amaranth populations in Lambton and Stormont, Dundas and Glengarry in 2025. This species is extremely competitive and is known globally to have evolved resistance to nine different herbicide groups, with populations documented that are resistant to up to six herbicide modes of action simultaneously.”

Stay alert and scout fields for problem weeds and manage them effectively this spring. If there is a weed that is hard to identify or has not reacted to herbicide applications as you think it should, ask your local agronomist for a second opinion.  If there are still concerns, weed resistance testing is available in Ontario.  A resistant weeds dashboard is also available to better identify which weeds may be more challenging to control regionally across the province.

Crop Protection Hub

The Crop Protection Hub is a wonderful resource for management strategies for weeds, disease and insects. It also provides Ontario farmers with up-to date information about registered products and Integrated Pest Management approaches to crop protection. Explore the hub here.

Avian Influenza

Biosecurity when travelling from field to field is important to keep in mind, as avian influenza is often present in the area each spring. Ensuring you don’t step in bird droppings, staying away from poultry barns, and thoroughly cleaning your boots and field implements when moving from field to field are always good practices. More information on biosecurity tips can be viewed here.