Knowledgebase

DLI Requirement for Citrus #680946

Asked February 15, 2021, 4:36 PM EST

I have a wall of south facing windows and want to use that for indoor plants, like citrus and herbs. I am deciding if I need supplemental lighting, how strong it should be (and the distance). So I am using PPFD measurements to make some decisions. I have three questions: 1. What is the suggested DLI range for an citrus tree (meyer lemon tree, as an example)? 2. Is the DLI different depending on the season (like when it is flowering or producing fruit?) 3. If I have enough light indoors, should the citrus still be taken outside in the summer months in Michigan? OR can I keep it indoors so as not to introduce pests when I bring it back in for winter.

Cheboygan County Michigan

Expert Response

Hello, 

I am not familiar with the DLI requirements for citrus. As they are native to warm-loving climates with extensive, intense sunshine (California, Florida) - the more light the better. There are publications on the best DLI for many plants: https://www.extension.purdue.edu/extmedia/HO/HO-238-W.pdf 

Keep in mind that it is extremely hard to get to any of those light levels during the winter months in Michigan. In a greenhouse in Michigan in Dec-February our DLI in a greenhouse could be as low as 1-3 mols/m2/d. I would assume that the plants would need more light in order to produce fruit. I'd suggest contacting the author of that bulletin, Dr. Roberto Lopez, <personal data hidden> for more information. He personally grows many houseplants as well. 

Thank you, 

Heidi Lindberg, MS Replied February 18, 2021, 8:48 AM EST

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