plant science

Hemp Outreach and Research Initiatives at CAHNR

hemp plants growing under glass in a UConn CAHNR research lab
Photo: Jessica Lubell

The UConn CAHNR Hemp Research and Outreach team has members from Extension and the UConn Department of Plant Science and Landscape Architecture. We have a suite of resources available for commercial growers. Our recent workshop was full, and the presentations and other resources are at

Interveinal Chlorosis

One of the most common plant-problems we see in the lab is interveinal chlorosis. This issue can affect house plants and garden vegetables, to landscape trees and shrubs. We often get inquires about the plant-tissue analysis we offer in the soil testing lab as a means to identify various problems. While this is an extremely useful tool for diagnosing nutrient deficiencies, when we see a plant showing interveinal chlorosis, we usually check the soil test results first.

What is interveinal chlorosis? A good place to start is defining what chlorophyll is. Greek for green leaf, chlorophyll is the pigment in plants that gives them their green color, and traps the light necessary for photosynthesis. Photosynthesis is the process in which plants produce sugar from light energy. The chlorophyll molecule is held together by a central Magnesium ion. Interveinal Chlorosis is a yellowing of the tissue between the veins of a leaf due to the decline of chlorophyll production and activity. A give-away tell of interveinal chlorosis is that the veins generally retain their green color, hence the name, interveinal. When a plant cannot produce chlorophyll it loses its green color and could face stunted growth, fail to produce fruit and flowers, and eventually die.

What causes interveinal chlorosis? The quick version is nutrient deficiency. We already know that Magnesium is a central part in chlorophyll, but there are other essential elements like Iron, Manganese, and Molybdenum that are necessary in many enzyme activities, and a deficiency in one of these nutrients can lead to interveinal chlorosis. In our lab we most commonly see interveinal chlorosis caused by a lack of Iron or Magnesium. When thinking about a nutrient deficiency, it’s important to remember that there are other factors to take into account than just whether the nutrient is present in your growing media. Interveinal Chlorosis brought on by a nutrient deficiency can be caused by a pH imbalance, injured roots or poor root growth, and excessive amounts of other available nutrients in your growing media.

How can you get rid of interveinal chlorosis? We are available in the lab, and in the Home & Garden education center to help you figure out what’s causing your interveinal chlorosis. Once you determine what the cause is, fixing the problem shouldn’t be too difficult. Most of the time it’s a pH issue. If your soil is too alkaline, generally having a pH value of over 6.7, iron becomes more insoluble and less available for absorption. Soil pH can be corrected using a few different approaches, the most common method for acidifying soil is adding Sulfur. Generally, 1 lb Sulfur/100 sq ft will lower pH ~ 1 unit. Nutrient deficiencies can also be remedied using foliar and trunk applications, as well as soil treatments amendments.

More information on diagnosing and remedying interveinal chlorosis can be found through the UConn Home & Garden Education Center and the UConn Soil Nutrient Analysis Lab. Information on foliar fertilization can be found here: Happy Gardening!

Tomato plant leaf with magnesium deficiency.


Originally published by the UConn Home & Garden Education Center