Variable weather conditions across the province over the last week have led to a range of planting progress. Areas of the southwest are well into spring planting, with some areas estimating over 50% of the crop acres planted, while others are just getting started with field work. Growing Degree Days (GDD) are behind last year, but are above or on par with the 10-year norm for most stations across the province.
Cereals
Winter wheat survival across the province has been good, with few reports of damage. Fields in the east are approaching GS30-31, while areas of the southwest are approaching GS32-37. Some fields are exhibiting sulphur deficiency symptoms, despite receiving a sulphur application earlier in the spring or previous manure applications. Cold, dry conditions this spring have slowed sulphur mineralization, and have prevented sulphur fertilizer moving into the soil solution, reducing available nutrient for uptake. With recent rainfall events fields are showing signs of improvement.
Disease levels to date have been low; however, in some fields powdery mildew is at medium to high pressure, particularly where the stands are thick, and the variety being grown is susceptible. With the approaching T1 fungicide timing, growers should be conscious of how many products are in the tank mix. It’s recommended to keep water volumes high on labelled tank mixes that contain more than 2 products (i.e., fungicide, herbicide, PGRs, and foliar nutrients).
Corn
Corn planting continues to progress across the province, despite some areas experiencing slight delays due to rain. Some regions are estimated to be more than 50% planted, while others are just getting started at 5 to 10%. Fertilizer and manure applications are well underway in preparation for planting.
The earliest planted corn in the southwest has emerged, in some cases 10 days or more after planting, due to cool temperatures. There is some concern about cold nighttime temperatures in the forecast, but the growing point remains underground at this stage of growth and should have minimal impact.
Soybeans
Soybean planting is also well underway over the last week, with many growers selecting to plant beans prior to corn, or at the same time as corn, if they have the capability. It’s estimated that planting progress for soybeans is still below 10%, with many areas below 5%. Ontario-based research has shown that there is a wide window to plant soybeans, with only a 1-2 bu/ac yield difference. Yield losses from soybeans planted into unfit conditions can create yield losses of more than 10 bu/ac.
Weed Control
Recent rainfalls and warm temperatures across Ontario have created ideal conditions for weed growth. Fields that haven’t been tilled or treated with herbicides are noticeably more weedy. As weeds grow larger and denser, it’s important to use the highest labeled rate of herbicides and maintain the highest recommended water carrier volumes for contact herbicides.
Forages
Much of the alfalfa seeded last fall has survived the winter well and is enjoying the recent warmth and rain. Feed inventories are still quite good, so it is anticipated that many older stands (3-5 years) will be terminated and planted into corn or will be terminated after first cut and rotated into soybeans. Fall rye and triticale is advancing rapidly, with some areas anticipating harvest for forage late next week.
Canola
Winter canola is flowering in southern Ontario. There is a high risk of white mould in the dense, moist canola canopy, so fungicide application is recommended. The risk of infection begins when the flower petals begin to fall off. Fungicide labels indicate applications should be made at 20 to 50% bloom, which roughly translates to 14 to 25 flowers open on the main stem (do not count flowers on side branches). In warm conditions, canola can move from first flower to 30% bloom in 10 days.
Spring canola seeding typically begins in early May, as soil conditions allow.
Agricorp
The deadline to apply for coverage or make changes to plans is May 10th. Since that is a Saturday, growers are encouraged to contact Agricorp on or before May 9th. Please visit www.agricorp.com for planting deadlines, and up-to-date information.
Exeter Breakfast Meeting – May 6th, 2025
Wheat
- Sulphur deficiency symptoms are evident in fields, including in fields that received a sulphur application this spring and fields with a history of manure applications.
- Some reported that fields that have received minimal rainfall after an application of ammonium sulfate (AMS) were showing signs of a deficiency, but with recent rainfall, have improved. Those fields that received higher rates of sulphur are showing fewer signs of a deficiency. With the cool, dry temperatures, mineralization of sulphur has been slow.
- There are more striping and application patterns showing up in fields compared to previous years. This includes both nozzles and bars. 3 stream nozzles appear to be the worst. Symptoms are primarily showing up on heavy clays that have received little to no rain. Moisture does not migrate in clay the same way it does in nice loam soils.
- The yield impact on fields with striping, misses, or no nitrogen applied was discussed. If a field has sufficient tillering in the fall and does not receive a nitrogen application prior to GS32, the yield impact is minimal. If there is minimal tillering in the fall and a field does not receive a nitrogen application, the yield impact will be greater and earlier than GS32. Prior Ontario research shows that 10 out of 12 locations that did not receive a nitrogen application prior to GS 32 saw no yield impact.
- As fields are at the ideal staging for PGR, T1 fungicide, and herbicide applications, there is a need to think about what is really needed in the tank. As weeds advance, there is a need to think about whether an herbicide application is required and what is being targeted. Dandelion and chickweed are beginning to flower and are beyond the ideal window for control. Bluegrass is also advancing with the ideal control window closing. At this point, herbicide applications for these weed species are more about weed seed set than full weed control. Fields damaged by snow mould that have gaps in the stand are worth spraying to keep weeds in those areas under control. Fields that received a fall herbicide application are generally dandelion-free.
- If mixing fungicides with herbicides, it is recommended to go with a higher water volume to minimize risk of leaf burn that can occur with some varieties.
- Disease pressure in wheat fields to date has been low. Stripe rust has not yet been reported in Ontario and continues to be monitored in nearby U.S. states. Powdery mildew is being found at medium to heavy pressure in some fields where susceptible varieties are being grown.
- Growing degree day accumulations are behind 2024 but are similar to 2023.
Ontario Growing Degree Day (GDD) data (2025, 2024, 2024 and 10 year average). Source: Ontario Pest and Weather System (PAWS)
Winter canola
- If trying to control winter cereals in the fall, Select (clethodim) should be avoided as injury to canola plants has been observed. Spring applied Select is fine.
Corn
- Some areas have 50-70% of the corn planted while other growers are waiting to start once the conditions will allow. The variable rainfall over the last week has influenced who has planted.
- Lots of land preparation is complete, with manure and fertilizer applied. Herbicide applications are also being made. Once the conditions allow, it is expected that planting will go fairly quickly.
- Long term data from Dave Hooker and Horst Bohner shows that there is a wide planting window before yields begin to drop off so there is plenty of time for growers to plant.
Soybeans
- It is estimated that 10% of soybeans in the area have been planted. It was noted that there are more people seeding beans when they could be planting corn.
- Some areas are still too wet to plant and some growers in those areas are struggling to get nitrogen on wheat.
- Ontario research shows that there is a large planting window before yields begin to drop off for soybeans. At Elora, they can be planted well into May before yields begin to decrease. In Ridgetown, yields really begin to drop by mid-June.
- It was noted that growers are currently managing risk, and although they may choose to wait a week to plant and give up 1 or 2 bushels, they are better off than trying to mud it in and lose 10 bu/ac or more.
- It wasn’t too early to plant the last week of April this year. Soybeans planted in April look fine and are in good shape. April beans should be planted shallower than is typical. ¾ to 1” is lots.
- Herbicides have been applied, but in the case of IP soybeans, growers are encouraged to time it as close as possible to planting, but up to two weeks prior is fine.
Edibles
- No edible beans have been planted to date. Aduzkis are expected to be seeded first. Eragon should not be used prior to planting edible beans.
Weed control
- Fields that received a pass with a high-speed disk may see weed regrowth with the recent rains. Dandelions or other larger weeds may have a large taproot that is still intact. The rate of glyphosate being applied to those fields should be based on the weed size.
- The group discussed the efficacy of Eragon on all the cloudy days. Higher water volumes and a higher rate of glyphosate will help. Efficacy is going to depend on the size of the fleabane rosettes. If it hasn’t bolted yet, it is expected to this week with the heat.
- If going with Dicamba or Enlist, course or extremely coarse nozzles must be used, but Eragon LQ likes finer droplets, so ensure the adjuvant is being added. The time of day is also important, with the ideal window being between 9 a.m. to 6 p.m. in the spring and 9 a.m. to 3 p.m. in the fall. The sunlight during these windows is needed to break down the cell membrane, which is what causes the Group Eragon LQ to work.
- If applying residual herbicides, streamer nozzles are not recommended as there is a risk of streaking.
Winchester Meeting Minutes – May 7th, 2025
Cereals
- Very low amounts of winterkill in wheat, mostly in low-lying, ponding areas
- Where the wheat is good, it’s excellent
- Most is at GS32/T1.5-2, lots at GS30,
- You typically want 250 GDDs to time PGRs (or if dandelions are flowering, you’re usually close to timing)
- Not a lot of low nighttime temps in the forecast to worry about
- Watch surfactant load and read labels when tank mixing (herbicide, fungicide, PGR)
- The plant must be able to metabolize it
- Higher water volume can help take a bit of the pressure off
- Watch the mixing order.
- Some spring cereals were planted this past weekend.
- Some red clover was put on with drones; the application window was quite small.
- May 15th is the planting deadline for spring wheat with Agricorp
- Rye is coming ahead in the last week or so – anticipating cut/harvest window for later next week.
Canola
- Not a lot of winter survival in Eastern Ontario
Forages
- Out of dormancy, and growing
- Early first cut, expected to rotate older stands out to either soybeans or corn (Will depend on soil moisture/forecast at first cut timing)
- New seeding window is starting to narrow, some growers got it in in good time, but not an abundance of acres are planned to go into rotation.
- Alfalfa snout beetle found in the Almonte/Perth which is a new location.
Corn
- 7-10% planted, some guys as high as 40%, others lower than 5%
- Already, some are asking about switching varieties (2850 down to 2600), but local research shows minimal yield differences in corn planted May 10th to May 20th.
- Forecast says to anticipate the emergence of crops quite quickly in the coming week.
- Row cleaners are not a tillage tool; they’re to manage residue.
- Marginal conditions will outweigh planting date if you’re rushing into unfit conditions.
Soybeans
- Maybe 5% in, some guys are going, and lots have not yet started.
- Letting retailers know about any big program changes in the fall can help with forecasting for product inventory this time of year (i.e., switching from Xtend to Enlist, etc.)
Weeds
- Lots of fleabane rosettes
- Lots of weeds at various stages
- Lower dandelion pressures – could be attributed to fall applications?
- Later planting last year meant herbicide went on a bit later, which may have controlled more.
- Heat next week will likely bring on another flush of weeds.
- Watch for the PRE window – it’s going to be easy to miss this year.
Insects
- First report of true armyworm moth in traps this week
Simcoe Breakfast Meeting – May 7th, 2025
Synopsis
- A lot of the area, especially on lighter soils, has some corn and soybeans planted, but very little has emerged yet. Clay soils were fit to plant at the end of April, but growers decided to wait for weather that would allow more rapid emergence. An open fall has resulted in fewer no-till acres in the area, and a drier than normal early spring is allowing soils, especially heavy-textured soils, to work up into a good seed bed for planting. A lot of fields have been worked, with fertilizer, manure, and burndown (pre-plant incorporated or pre-emerge herbicides applied but recent rains have put planting on hold. Planting is expected to progress rapidly as soil conditions become fit.
Cereals
- Wheat over the whole region looks excellent and is approaching GS32. One early September-planted field has flag leaf emerging. Herbicide application is nearing completion and excellent fall tillering has increased interest in T1 fungicide application along with PGR to reduce lodging risk. There is a lot less weed pressure in fields that had weed control applied last fall.
- Sulphur deficiency symptoms are evident in many fields, including fields with a history of manure applications. With the cool, dry temperatures, mineralization of sulphur has been slower. 3 gallons of ATS (Ammonium Thiosulfate) has been enough to eliminate deficiency symptoms.
- Spring grains and new seedings are emerging with uniform stands.
Forages
- Alfalfa forages have come out of the winter with uniform and good early growth. 1st cut for dairy is on target to begin in late May.
- Forage triticale and rye stands are generally uniform and are advancing well. The earliest harvest could occur by late next week.
Winter Canola
- There is more winter kill evident in fields this spring, especially where drainage is an issue. South-facing slopes appear to have better winter survival than north-facing slopes. Fall planting into dry soils resulted in later germination and reduced growth going into winter.
Corn
- There were a lot of acres planted in the last week of April. Although very little has emerged so far, there is minimal concern as corn has taken over 3 weeks to emerge in previous years with no negative impact on the stand.
Soybeans
- Soybean planting was occurring simultaneously with corn planting, but hard to estimate what percentage has been planted to date. Some growers were waiting for the “cold rains” to pass before starting planting.
Weed Control
- Bean fields where herbicides with residual activity were applied last year are easy to pick since they have a lot less weed pressure. There are still some fields that have only glyphosate applied. There is an opportunity for industry to continue to educate, especially in a few specific geographies, on the importance of using herbicides with residual activity as well as herbicide rotations for crop safety, with more diverse rotations that include more cover crops and fall-seeded crops. Using cover crops to reduce weed pressure is a great message, but does not eliminate the value of residual herbicides.
- A reminder to verify with growers of their soybean varieties ahead of herbicide application. Verify which “E” variety, since application of the wrong herbicide, resulting in a field with dead beans, is not an insurable peril.
Vegetable crops
- Most growers are planting the intended vegetable crops despite tariff risk.
- Asparagus harvest has begun. A lot of sweet corn, peppers and zucchini have been planted; most under plastic. Transplants of peppers, watermelon and tomatoes are starting. There are more tobacco acres planned for this year. Fruit trees range from early to full bloom.
- Apiaries are dealing with high bee mortalities, in some cases 50% or higher. Hives are being repopulated with queens from other countries, allowing the availability of hives for pollinating crops.
OMAFA Weather Summary: Thurs May 1—Wed May 7, 2025
| Location | Highest Temp (°C) | Lowest Temp (°C) | Rain for Week (mm) | Rain Since April 1st (mm) | GDD0C April 1st | GDD5C April 1st | CHU May 1st |
| HARROW | |||||||
| 2025 | 22.1 | 5.9 | 66.6 | 143.9 | 341 | 178 | 76 |
| 2024 | 26.2 | 8.0 | 12.7 | 136.7 | 430 | 244 | 123 |
| 2023 | 23.7 | 2.9 | 10.4 | 64.1 | 346 | 172 | 58 |
| 10 YR Norm (2011-2020) | 18.7 | 6.6 | 25.4 | 115.0 | 316 | 134 | 94 |
| RIDGETOWN | |||||||
| 2025 | 22.0 | 3.6 | 41.2 | 102.5 | 319 | 159 | 77 |
| 2024 | 24.7 | 4.2 | 8.9 | 134.3 | 390 | 208 | 107 |
| 2023 | 20.8 | 2.1 | 13.5 | 113.9 | 321 | 156 | 47 |
| 10 YR Norm (2011-2020) | 18.7 | 5.1 | 21.3 | 98.3 | 279 | 102 | 81 |
| SARNIA | |||||||
| 2025 | 20.2 | 3.8 | 33.4 | 149.9 | 303 | 149 | 65 |
| 2024 | 27.4 | 3.3 | 18.3 | 99.8 | 381 | 202 | 99 |
| 2023 | 20.9 | 1.9 | 9.5 | 106.0 | 326 | 161 | 46 |
| 10 YR Norm (2011-2020) | 18.3 | 4.4 | 15.8 | 99.0 | 264 | 89 | 67 |
| LONDON | |||||||
| 2025 | 20.1 | 5.9 | 30.1 | 139.0 | 297 | 149 | 84 |
| 2024 | 23.3 | 6.5 | 11.3 | 121.7 | 389 | 204 | 121 |
| 2023 | 19.8 | 1.2 | 21.8 | 150.4 | 312 | 148 | 46 |
| 10 YR Norm (2011-2020) | 18.4 | 5.2 | 17.8 | 107.4 | 270 | 96 | 82 |
| BRANTFORD | |||||||
| 2025 | 21.8 | 5.9 | 34.3 | 130.6 | 302 | 150 | 68 |
| 2024 | 23.4 | 5.0 | 10.6 | 91.6 | 355 | 175 | 110 |
| 2023 | 19.2 | 1.1 | 16.3 | 120.0 | 301 | 134 | 36 |
| 10 YR Norm (2011-2020) | 19.1 | 3.8 | 18.8 | 119.3 | 252 | 82 | 75 |
| WELLAND | |||||||
| 2025 | 20.0 | 6.1 | 28.9 | 83.8 | 311 | 155 | 87 |
| 2024 | 23.3 | 4.4 | 12.0 | 117.2 | 382 | 198 | 118 |
| 2023 | 19.5 | 2.2 | 18.0 | 116.1 | 319 | 147 | 39 |
| 10 YR Norm (2011-2020) | 17.8 | 4.4 | 19.6 | 113.9 | 274 | 99 | 79 |
| GODERICH | |||||||
| 2025 | 20.1 | 2.8 | 12.8 | 90.9 | 265 | 119 | 54 |
| 2024 | 23.7 | 4.3 | 5.5 | 93.8 | 334 | 161 | 86 |
| 2023 | 17.9 | -0.3 | 25.0 | 85.4 | 278 | 128 | 35 |
| 10 YR Norm (2011-2020) | 16.0 | 4.1 | 11.4 | 87.9 | 226 | 61 | 55 |
| ELORA | |||||||
| 2025 | 21.7 | 4.2 | 28.1 | 125.5 | 264 | 123 | 62 |
| 2024 | 22.1 | 3.0 | 22.0 | 120.0 | 310 | 138 | 94 |
| 2023 | 17.7 | 0.3 | 22.6 | 106.5 | 263 | 114 | 24 |
| 10 YR Norm (2011-2020) | 16.7 | 3.4 | 18.7 | 111.7 | 216 | 56 | 63 |
| MOUNT FOREST | |||||||
| 2025 | 18.4 | 3.4 | 13.9 | 98.7 | 260 | 122 | 63 |
| 2024 | 22.4 | 3.0 | 5.4 | 129.6 | 306 | 139 | 94 |
| 2023 | 18.4 | 0.3 | 28.2 | 134.2 | 267 | 122 | 28 |
| 10 YR Norm (2011-2020) | 16.8 | 3.7 | 16.4 | 99.1 | 204 | 52 | 62 |
| BARRIE | |||||||
| 2025 | 19.1 | -0.2 | 15.8 | 95.4 | 233 | 97 | 68 |
| 2024 | 22.6 | 3.0 | 3.6 | 199.5 | 283 | 115 | 90 |
| 2023 | 18.5 | 1.9 | 16.9 | 120.6 | 264 | 113 | 30 |
| 10 YR Norm (2011-2020) | 17.7 | 1.9 | 17.8 | 99.5 | 197 | 47 | 61 |
| PETERBOROUGH | |||||||
| 2025 | 21.8 | 0.5 | 31.3 | 105.6 | 267 | 121 | 92 |
| 2024 | 22.1 | 2.8 | 8.5 | 152.7 | 309 | 136 | 101 |
| 2023 | 20.4 | 0.4 | 6.8 | 105.3 | 292 | 130 | 36 |
| 10 YR Norm (2011-2020) | 18.7 | 2.3 | 19.4 | 101.0 | 225 | 63 | 70 |
| KEMPTVILLE | |||||||
| 2025 | 22.4 | -1.2 | 17.2 | 107.1 | 274 | 125 | 101 |
| 2024 | 23.0 | 4.9 | 16.6 | 139.7 | 312 | 139 | 106 |
| 2023 | 22.4 | 3.5 | 33.7 | 175.3 | 309 | 152 | 46 |
| 10 YR Norm (2011-2020) | 19.2 | 3.5 | 21.0 | 108.8 | 238 | 78 | 74 |
| SUDBURY | |||||||
| 2025 | 24.1 | -4.5 | 23.1 | 90.8 | 151 | 47 | 49 |
| 2024 | 23.4 | 2.9 | 10.6 | 200.9 | 223 | 80 | 87 |
| 2023 | 18.6 | 0.6 | 43.1 | 150.1 | 187 | 78 | 32 |
| 10 YR Norm (2011-2020) | 16.0 | 0.7 | 14.7 | 98.6 | 125 | 26 | 44 |
| EARLTON | |||||||
| 2025 | 22.0 | -3.4 | 12.0 | 80.2 | 125 | 36 | 45 |
| 2024 | 22.0 | 1.7 | 20.2 | 161.3 | 209 | 73 | 86 |
| 2023 | 19.7 | 1.4 | 21.8 | 116.2 | 188 | 75 | 49 |
| 10 YR Norm (2011-2020) | 16.7 | -0.1 | 11.6 | 77.8 | 101 | 24 | 52 |
| SAULT STE MARIE | |||||||
| 2025 | 23.2 | -0.8 | 13.5 | 109.4 | 159 | 44 | 41 |
| 2024 | 20.4 | 0.4 | 31.1 | 168.5 | 231 | 73 | 65 |
| 2023 | 17.1 | -0.1 | 43.0 | 121.9 | 184 | 73 | 26 |
| 10 YR Norm (2011-2020) | 15.0 | -0.3 | 9.7 | 93.9 | 119 | 20 | 41 |
| THUNDER BAY | |||||||
| 2025 | 23.1 | -2.8 | 7.9 | 112.3 | 110 | 18 | 41 |
| 2024 | 19.8 | -1.7 | 18.7 | 76.7 | 177 | 43 | 49 |
| 2023 | 11.3 | -2.9 | 8.8 | 90.4 | 113 | 25 | 6 |
| 10 YR Norm (2011-2020) | 14.6 | -0.7 | 10.1 | 59.6 | 103 | 14 | 40 |
| FORT FRANCES | |||||||
| 2025 | 27.9 | 1.5 | 3.7 | 71.0 | 175 | 56 | 68 |
| 2024 | 22.1 | -1.9 | 17.7 | 55.3 | 192 | 47 | 51 |
| 2023 | 22.9 | -2.4 | 14.1 | 55.5 | 143 | 50 | 51 |
| 10 YR Norm (2011-2020) | 17.2 | -0.9 | 8.4 | 52.0 | 130 | 23 | 48 |
This weather summary is compiled by OMAFA using Environment Canada weather station data provided by Agriculture and Agri-Food Canada. Data quality is verified but accuracy is not guaranteed and should be used for general information purposes only. For additional locations and weather analysis, visit the OMAFA Pest and Weather System (PAWS)