DLI and PPFD Monthly Report for Leamington/Kingsville and Niagara

Daily light integral (DLI) meter in front of a greenhouse, clear sunny sky.

July, 2026 DLI Report

Published on August 11, 2026August 10, 2026 by Averie Mastronardi

Summary

DLI data were available for the second to the third week of July for Leamington-Kingsville. The average DLI for the month of July for Leamington-Kingsville was 57 moles/m²/day. The maximum DLI was 74 recorded on July 12^th, and the minimum DLI was 41 recorded on July 17^th.

DLI data were available for most of July for Vineland. The average DLI for the month of July for Vineland was 51 moles/m²/day. The maximum DLI was 68 recorded on July 12^th, and the minimum DLI was 15 recorded on July 15^th.

Leamington-Kingsville received approximately 7% less light in July than in June. The monthly DLI average for July 2026 is 5% lower than it was in July 2025.

Vineland received 4% more light in July than June. Vineland received 11.7% less light than Leamington-Kingsville.

Listen to the monthly DLI radio report or read the transcript of the radio report below. It airs on the second Tuesday of every month on Country 91.3 during the Noon Farm Show.

Hello. Welcome to the monthly daily light integral (DLI) report for the regions of Windsor-Essex and Niagara.

I’m Averie Mastronardi, Greenhouse Research Assistant with the Ontario Ministry of Agriculture, Food and Agribusiness (OMAFA).To learn more about our DLI data collection project visit the ONGreenhouseVegetables.ca blog or the ONFloriculture.com blog.

DLI is the total amount of light within the photosynthetically active radiation spectrum that impacts a surface in one day, and it is measured in moles per metre squared per day. It is important to greenhouse production because it represents the amount of light that is available to the crop for photosynthesis and can be used to adjust the growing environment to optimize crop yield.

The data provided here reflects outdoor light, which can be significantly higher than light levels inside greenhouses. The desired DLI inside a greenhouse is different for each crop. You can find more information on DLI levels for greenhouse fruit and vegetable crops in the OMAFA production guides available on the ONGreenhouseVegetables.ca blog.

Leamington-Kingsville received approximately 7% less light in July than in June. The monthly DLI average for July 2026 is 5% lower than it was in July 2025.

Vineland received 4% more light in July than June. Vineland received 11.7% less light than Leamington-Kingsville.

The next monthly DLI radio report will be on Tues, Sept. 8^th.

Thanks for your attention, and have a great day.

Continue Reading: July, 2026 DLI Report

June, 2026 DLI Report

Published on July 14, 2026August 6, 2026 by Averie Mastronardi

Summary

DLI data were available for two and half weeks in June for Leamington-Kingsville. The average DLI for the month of June 2026 for Leamington-Kingsville was 61 moles/m²/day. The maximum DLI was 73.1 recorded on June 7th, and the minimum DLI was 38.9 recorded on June 21st.

DLI data were available for two weeks in June for Vineland. The average DLI for the month of June for Vineland was 49 moles/m²/day. The maximum DLI was 75.1 recorded on June 6th, and the minimum DLI was 22.8 recorded on June 25th.

Leamington-Kingsville received 22% more light in June than May. The monthly DLI average for June 2026 was 15% higher than it was in June 2025.

Last month’s data were not available for Vineland but compared to April it received 53% more light in June. Vineland received 20% less light than Leamington-Kingsville.

Listen to the monthly DLI radio report (below) that airs on the second Tuesday of every month on Country 91.3 during the Noon Farm Show.

Continue reading →

May, 2026 DLI Report

Published on June 9, 2026June 9, 2026 by Averie Mastronardi

Summary

The average DLI for Leamington-Kingsville for May was 50 moles/m²/day. The maximum DLI was 71.5 recorded on May 30th, and the minimum DLI was 11.7 recorded on May 23rd.

Leamington-Kingsville received 16% more light in May than April. The monthly DLI average in May 2026 was similar to the average DLI recorded in May 2025, with only a 9% increase this year.

DLI data for Vineland was not available for May.

Listen to the monthly DLI radio report (below) that airs on the second Tuesday of every month on Country 92.9 during the agriculture show at noon.

Continue reading →

April, 2026 DLI Report

Published on May 12, 2026May 21, 2026 by Fadi Al-Daoud

Summary

DLI data for the last two weeks of April were available for Leamington-Kingsville. Average DLI for the month of April, 2026 for Leamington-Kingsville was 43 moles/m²/day. The maximum DLI was 63.1 recorded on April 20^th, and the minimum DLI was 14.8 recorded on April 29^th.

The average DLI for the month of April for Vineland was 32 moles/m²/day. The maximum DLI was 56.5 recorded on April 22^th, and the minimum DLI was 10.1 recorded on April 29^th.

Leamington-Kingsville received 79% more light in April than March. The monthly DLI average for April, 2026 was similar to 2025, but the last week of April (week 17) received 22% less light in 2026 than 2025.

Vineland received 45% more light in April than March, but it received 26% less light than Leamington-Kingsville.

Listen to the monthly DLI radio report (below) that airs on the second Tuesday of every month on Country 92.9 during the agriculture show at noon.

Continue reading →

March, 2026 DLI Report

Published on April 14, 2026 by Fadi Al-Daoud2 Comments

Summary

DLI values for only the first three weeks of March were available for Leamington-Kingsville. The average DLI for the month of March, 2026 for Leamington-Kingsville was 24 moles/m²/day. The maximum DLI was 41 recorded on March 9^th, and the minimum DLI was 5 recorded on March 5^th.

The average DLI for the month of March for Vineland was 22 moles/m²/day. The maximum DLI was 38.5 recorded on March 27^th, and the minimum DLI was 4.2 recorded on March 22^th.

Leamington-Kingsville received 9% more sunlight in March than in February, but it received 27% less sunlight this March than last March.

Listen to the monthly DLI radio report (below) that airs on the second Tuesday of every month on Country 92.9 during the agriculture show at noon.

Continue reading →

February, 2026 DLI Report

Published on March 10, 2026April 13, 2026 by Fadi Al-Daoud

Summary

Leamington-Kingsville received approximately 57% more sunlight in February than January, 2026, and it received around the same levels as last year with only 5% more sunlight this February than last February.

Vineland received approximately 58% more light in February than January, 2026.

The average DLI for the month of February, 2026 for Leamington-Kingsville was 22 moles/m²/day. The maximum DLI was 32.5 moles/m²/day recorded on February 27^th, and the minimum DLI was 7 recorded on February 20^th.

The average DLI for the month of February, 2026 for Vineland was 19 moles/m²/day. The maximum DLI was 33.3 moles/m²/day recorded on February 26^th, and the minimum DLI was 2.9 moles/m²/day recorded on February 18^th.

Listen to the monthly DLI radio report (below) that airs on the second Tuesday of every month on Country 92.9 during the agriculture show at noon.

Continue reading →

January, 2026 DLI Report

Published on February 10, 2026February 10, 2026 by Fadi Al-Daoud

Summary

Leamington-Kingsville received approximately 40% more light in January, 2026 than December, 2025, but it was around 25% less than last January, 2025.

Vineland received approximately 50% more light in January, 2026 than December, 2025.

The average DLI for the month of January, 2026 for Leamington-Kingsville was 14 moles/m²/day. The maximum DLI was 22 moles/m²/day recorded on January 23^th, and the minimum DLI was 6 recorded on January 9^th.

The average DLI for the month of January, 2026 for Vineland was 12 moles/m²/day. The maximum DLI was 24 moles/m²/day recorded on January 30^th, and the minimum DLI was 4 moles/m²/day recorded on January 12^th.

Listen to the monthly DLI radio report (below) that airs on the second Tuesday of every month on Country 92.9 during the agriculture show at noon.

Continue reading →

December, 2025 DLI and PPFD Data

Published on January 13, 2026January 14, 2026 by Fadi Al-Daoud

Summary

Leamington-Kingsville and Vineland received approximately 1/3 less light in December than November.

The average DLI for the month of December, 2025 for Leamington/Kingsville was 10 moles/m²/day. The maximum DLI was 18.1 recorded on December 4^th, and the minimum DLI was 2 recorded on December 26^th.

The average DLI for the month of December, 2025 for Vineland was 7.9 moles/m²/day. The maximum DLI was 14.7 recorded on December 5^th, and the minimum DLI was 1.8 recorded on December 26^th.

Listen to the monthly DLI radio report (below) that airs on the second Tuesday of every month on Country 92.9 during the agriculture show at noon.

Background

We mounted a daily light integral (DLI) meter on the border of Leamington and Kingsville, Ontario, in 2024, and another DLI meter at the Vineland Research and Innovation Centre (VRIC) in Vineland, Ontario, in 2025 to give greenhouse producers in those areas access to readily available light data.

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