Nitrogen deficiency in strawberry plants can cause rather significant problems for the longevity and vitality of strawberry patch. If your soil is low in nitrogen, you can expect consequences. This post will cover the basics of what to look for to determine whether or not your strawberries lack sufficient nitrogen-containing soil for optimal health and vigor.
What Indicates Nitrogen Deficiency in Strawberries?
In order to confirm nitrogen deficiency in strawberry plants, one ultimately must take a few tissue samples from affected leaflets that are “middle aged.” The leaflets that must be sampled cannot be the old ones toward the bottom of the plant or the new, bright green ones emerging from the crown.
Once samples are collected, they must be tested for average composition. The baseline measurement for nitrogen sufficiency is 2.6% to 2.8%. Should the measured percent composition of nitrogen be below 2.6% for the tested sample, it is very likely that the soil is nitrogen deficient, resulting in less-than-acceptable levels of nitrogen in the foliage tissue of the strawberry plants.
Strawberry Plants with Yellow Leaves
The old agricultural rule of thumb is that strawberry plants with yellow leaves indicate nitrogen deficient soil. However, while purple leaves often indicate a phosphorus deficiency, nitrogen deficiency can also cause purple leaves in addition to strawberries' yellow leaves.
Yellow Strawberry Plant Leaves – Why?
A nitrogen deficiency is manifest (and consequently visualized more easily) in the middle-aged leaves. The yellow strawberry plant leaves occur in these middle-aged leaves, primarily, and not the new, still-green leaves emerging from the crown. This is due to two factors.
First, nitrogen is a component in many amino acids. In plants that lack this vital nutrient, proper amino acid synthesis is unable to be completed. The lack of amino acids yield the discolorations. Additionally, purple strawberry leaves can also be attributed to nitrogen deficiency (instead of the more common phosphorus deficiency causing the purple leaves) when carbohydrates build up in the plant tissues due to problems with amino acid deficiency.
Second, the young leaves emerging from the crown exacerbate the deficient state of the middle-aged leaves by appropriating for themselves the nitrogen that otherwise would have been used in the older leaves. Due to the demand of metabolism and synthesis of the newly emerging foliage, nitrogen will be mobilized from the middle-aged leaves to the new ones. This leads to more severe color changes in those leaves, depending on the overall severity of the nitrogen shortage.
Nitrogen Deficiency in Strawberry Plants: Conclusion
If your strawberry plants have yellow leaves, the chances are good that they also have nitrogen deficiency. While not the only cause of yellow leaves (multiple other diseases can cause yellow or yellow-spotted leaves), it is surely a good idea to determine if your soil is lacking this crucial component. With the multitude of organic nitrogen fertilizers available today, the problem should be fairly easy to remedy. Just be sure to check the Growing Strawberries page to make sure everything is done correctly! And, to learn about other damaging strawberry diseases and strawberry pests, see the Strawberry Plant page.