Most of us know that houseplants need air, water, sunlight and nutrients to grow. But many of us have a difficult time figuring out which of these important, life-sustaining elements is the cause of our plant problems.
Air isn't too hard to figure out. Densely packed plants or those whose soil is saturated cannot get enough oxygen to live. Air needs to be able to flow freely around the plant, and it needs to be able to move through the soil to the roots. Give your plants space, and only water when the plant needs it, allowing the soil to dry between waterings.
Sunlight isn't too hard to figure out, either. All plants need some sunlight, but avoid direct sun for more delicate plants such as those with variegated leaves, ferns and delicate ivies. You'll notice burning of the leaves, lack of vibrant color and wilting on plants subjected to too much direct sun.
There are 16 nutrients that plants need to survive. In addition to carbon, hydrogen and oxygen, which are obtained from the air, the three primary nutrients needed by plants are nitrogen, phosphorous and potassium (the N, P and K, respectively, on fertilizer labels). Magnesium, calcium, zinc, iron, copper, sulfur, manganese, molybdenum, chlorine and boron are the other micronutrients required for a healthy plant.
Often, the symptoms of a plant will tell us which nutrients are deficient. Nitrogen deficiency is often seen when the entire plant is light green in color, growth is stunted and the lower leaves have turned yellow.
Stunted growth also may be a sign of phosphorous deficiency. Often, the entire plant turns a blue-green to red-purple color with desiccated lower leaves.
A lack of potassium often causes leaves to appear dry as parchment along the edges. A zinc deficiency also will create a yellowed, papery look to the leaves.
If the lower leaves have wilted and are yellow along the tips and between leaf veins, the plant may have a magnesium deficiency. A checkered pattern on the lower leaves could be a sign of manganese deficiency, while curled leaf edges that are dark green or bluish could be a sign that the plant needs more copper.
If leaves are yellow, but the leaf veins remain green, you could have a deficit of iron.
Molybdenum could be lacking if leaves are malformed or smaller than they should be and lacking a bright green color. Some spotting and red coloration may occur.
Boron deficiency is seen in plants in which the newest leaves show signs of scorch at their tips and edges.
If the plant is stunted, spindly and young leaves never gain the bright green color of older leaves, you may have a sulfur deficiency.
Keep in mind that other factors can cause symptoms that appear to be a nutrient deficiency. These other factors include pollution in the air, salt and other minerals in the water used to hydrate your plants, and diseases caused by insects and viruses. If a nutrient deficiency is causing the problem, often by adding the deficient nutrient to your fertilizer mix, you'll see remarkable recuperation of your plant within days.
Also, know that too much of any of these nutrients can harm your plant. Always read label directions on any fertilizers you use.
Deb Babcock is a Master Gardener through the Colorado State University Cooperative Extension Office in Routt County. Questions? Call 879-0825 or e-mail firstname.lastname@example.org.