DLI Data – October, 2025
We’ve recently mounted at daily light integral (DLI) meter at the Vineland Research and Innovation Center! As a result, the OnFloriculture blog will be making regular monthly posts detailing monthly DLI data for Vineland, Ontario.
This meter acts as a reliable record of light levels for Vineland and surrounding areas, giving growers and researchers easy access to data that may help explain crop outcomes. The information is neatly organized, allowing for quick month-to-month comparisons and a clearer understanding of light conditions throughout the growing seasons.
Background
OMAFA’s greenhouse vegetable specialist, Dr. Fadi Al-Daoud, mounted a DLI meter on the border of Leamington and Kingsville in June of 2024 for the concentration of growers in that area to have readily available and organized light data.
To give growers in the Niagara Region the same data availability, we mounted a DLI meter in Vineland in August of 2025.
DLI is the total amount of light within the photosynthetically active radiation (PAR) spectrum (light wavelengths of 400-700 nm) that impacts a surface in a day. It is measured in moles per metre squared per day (mol/m2/day).
Purpose
The DLI Data section of this blog provides greenhouse producers in the Niagara Region, Ontario with outdoor light levels on a regular basis year-round. It is meant to serve as a record of the amount of light this location received on a daily basis throughout the year.
Each blog post in this section contains tables with the available data for a one-month period and an Excel file with data from previous months.
NOTE: This data is provided for information purposes and does not represent the amount of light at other locations.
Materials and Methods
The data was collected using a DLI-600 sensor from Apogee Instruments. It measures the extended PAR (ePAR) spectrum (400-760 nm), which includes far red light. There are two sensors, both are placed 90 cm off the ground. One sensor is located outside of a greenhouse near the Leamington-Kingsville border in Ontario. The other is located at the Vineland Research and Innovation Center in Vineland, Ontario.
The data in this blog post represents the Vineland sensor only. If you are interested in the Leamington/Kingsville data, download the excel sheet at the bottom of this post or visit the OnGreenhouseVegetables blog.
Available DLI data is presented for each month in Figure 1 and Table 1, for each day (24 hr period) of the current month in Figure 2 and Table 2, and it is all available to download in the attached Excel sheet in the last section.
DLI Data
Figure 1: Monthly DLI data for Vineland
Table 1: Monthly DLI data for Vineland
| Month and Year (number of days of data) | DLI (mol/m2/day) (average ± standard deviation) |
| October, 2025 (21 days) | 25 (±11) |
| September, 2025 (17 days) | 44 (±10) |
| August, 2025 (20 days) | 47 (±16) |
Figure 2: Daily (24 hr period) DLI data for Vineland for October, 2025
Table 2: Daily (24 hr period) DLI data for Vineland for October, 2025
| Date (day/month/year) | DLI (mol/m2/day) |
| 02-Oct-25 | 27 |
| 03-Oct-25 | 40.7 |
| 04-Oct-25 | 39 |
| 05-Oct-25 | 39.7 |
| 06-Oct-25 | 38.6 |
| 07-Oct-25 | 7.4 |
| 12-Oct-25 | 34.2 |
| 13-Oct-25 | 22.3 |
| 16-Oct-25 | 35.3 |
| 17-Oct-25 | 11.5 |
| 18-Oct-25 | 28.1 |
| 19-Oct-25 | 16 |
| 23-Oct-25 | 20.4 |
| 24-Oct-25 | 16.5 |
| 25-Oct-25 | 19.1 |
| 26-Oct-25 | 27.3 |
| 27-Oct-25 | 25.6 |
| 28-Oct-25 | 27.5 |
| 29-Oct-25 | 29.5 |
| 30-Oct-25 | 3.3 |
| 31-Oct-25 | 10.7 |
| October, 2025 DLI average ± standard deviation | 24 (± 11) |
DLI and PPFD data Excel sheet
Tell us what YOU want
WE want your feedback!
If we can present or interpret this data in a different way that would be more beneficial to you, please let us know. If you have questions, comments or any feedback at all, please comment on this post or email:
Kathryn Russell, OMAFA Greenhouse Floriculture Specialist: kathryn.russell@ontario.ca
Dr. Fadi Al-Daoud, OMAFA Greenhouse Vegetable Specialist: fadi.al-daoud@ontario.ca
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