With plants in full bloom and summer going full steam ahead, I hope all the plants in your gardens and fields are a vibrant green. However, if things aren’t growing as they should be you could have a nutrient deficiency. Let’s talk about some of the common nutrient deficiencies, what their symptoms are, and what you can do to fix them.
Seventeen nutrients are essential for plant growth (give or take a couple depending on who you ask). Carbon, hydrogen, and oxygen are all taken from the air or water. The remaining 14 are divided into macronutrients and micronutrients.
The big three of nutrients are Nitrogen, Phosphorus, and Potassium. Plants that don’t have enough nitrogen will begin to turn yellow-green in the oldest leaves first. Because nitrogen is mobile in the plant, it will move nitrogen from the old leaves to new growth where it is needed. Nitrogen is also mobile in the soil, so it will leach out easily following a rainfall. Splitting up nitrogen applications over the course of the season is the best way to make sure it’s not wasted. Phosphorus deficiency will turn the leaves to a reddish-purplish color. Typically if you use a fertilizer like 10-10-10, 13-13-13, or 17-17-17 you won’t have issues with phosphorus deficiency, because you will most likely have applied more phosphorus than the plant needs. Potassium deficiency turns leaf edges brown and causes dead spots throughout the leaf. It can look similar to drought damage.
Not enough calcium leads to young leaves being cupped and yellow. Lack of calcium also causes blossom end rot. Poor watering can lead to a calcium deficiency because calcium requires a lot of water to move through the plant. Magnesium deficiency is yellowing between the leaf veins on old leaves. These yellow areas can turn brown and die. Epsom salts are good for plants that lack magnesium.
Sulfur deficiency will turn the entire plant a lime green color and cause the plant to be stunted. Lack of iron leads to leaves turning yellow, but the veins remain dark green. Some plants are sensitive to excessive iron or iron deficiency, which is controlled by the soil pH. Boron deficiency makes the youngest leaves turn light green and become distorted. It can also cause blackheart in vegetables. Not enough molybdenum makes narrow leaves with yellowing in between the veins. As the leaves expand, they are mottled. A manganese shortage shows up as yellow or white colored leaves with green veins. Zinc scarcity will be reddish colored spotting of older leaves between the veins. Copper shortage will show up as young leaves wilt but remain green.
Nutrient deficiency leads to plants that are more susceptible to disease because they are stressed. Diseases can cause a nutrient deficiency because the plant isn’t able to operate properly. Therefore, we can have a chicken or the egg type situation. Both issues will need to be addressed to make the plants healthy again.
The best way to avoid a nutrient deficiency is to do a basic soil test. It costs $10 and you can bring your soil sample to the Extension Office. The report that you get back will have instructions on when to fertilize and how much to use. If the plants you are growing have a unique nutrient requirement that information will be included as well.