Questions on gardening abound here at Gardening Know How. It’s our job, and our passion, to help answer those to the best of our knowledge. Plant issues in the garden are inevitable, regardless of how long you’ve been growing them. Even we have to fight pests, diseases, and other growing troubles. As you can imagine questions about problems in the garden are popular. Here are the 10 most commonly asked.
There are probably dozens of factors, but a few simple situations should be addressed. If the tips or edges of leaves are turning brown, the plant may be overfertilized. Brown leaves beginning at the tips and edges may indicate that a plant that isn’t receiving enough water, especially during the heat of summer. Brown splotches, spots, or streaks may be a sign of a fungal or viral disease, and some pests can also cause browning of leaves. Root rot, generally caused by overwatering or poorly drained soil, can cause the entire plant to turn brown and soft.
It’s normal for a few older leaves to turn yellow, but a lot of yellow leaves are a sign that something isn’t right. Yellow leaves may be caused by excessive sunlight, but leaves can also look faded or yellow in insufficient light. Too much or too little water can cause leaves to turn yellow, as can too much (or too little) fertilizer. Check closely for tiny, sap-sucking pests like aphids or mites. Root rot and other fungal diseases, often caused by overwatering, can cause plants to turn yellow. Indoor plants may simply need a larger container.
Too much fertilizer, particularly high-nitrogen fertilizer, can promote a lush, bushy plant with no flowers. Be careful not to kill your plant with kindness, and keep in mind that too little fertilizer is better than too much. Other factors that prevent a plant from flowering may include lack of sunlight, or conversely, too much hot, afternoon sunlight. Be sure plants are properly protected if your winters are cold, as cold weather can kill buds. Keep in mind that many plants rarely bloom during the first year, when the energy is focused on developing healthy roots.
If you notice black, sooty-looking dust on plant leaves, your plant is likely afflicted with a fungus known as “sooty mold.” The presence of sooty mold generally won’t kill the plant, although a thick layer can hinder photosynthesis by blocking sunlight. Sooty mold is usually fostered by sap-sucking insects such as aphids, scale, leafhoppers, mealybugs, or whiteflies, which leave behind a sweet liquid known as “honeydew” on the leaves. The sweet stuff creates nourishment for fungi to grown. Insecticidal soap or horticultural oil usually keeps honeydew-excreting pests in check.
Whether a plant comes back after a hailstorm depends on several factors, such as the time of year, type and maturity of the plant, and size of the hailstones. A hailstorm that occurs in spring can hammer seedlings to the point of no return, but a healthy plant damaged by a storm later in the season may rebound. If you think there’s a chance a plant will survive, give it a little extra TLC. Remove damaged growth and fertilize lightly after the storm. Water regularly and provide a layer of mulch to help the damaged plant survive the winter.
That weird blob in your garden is slime mold, often known as “dog vomit” for obvious reasons. The slimy mass, which typically shows up on wood mulch, is harmless and promotes the healthy, natural decomposition of the mulch. If you leave it alone, it will eventually morph from bright yellow or orange slime to a crusty, bluish or gray substance that soon breaks down into a brown powder. If the weird appearance bothers you, scrape the stuff into the trash or toss it into your compost bin.
Consider environmental conditions when plants turn red. Toxins in the soil, such as de-icer, fertilizer, or heavy metals may be the problem. Reddening may be caused by poor drainage or soil compaction, which can prevent the roots from getting enough oxygen. A soil test is a good idea, as most tests provide information about soil pH, nutrient levels, and possible soil contamination. Excessive sunlight and heat can cause plants to turn red, especially young plants that aren’t fully developed. Some plants may turn red in response to cold temperatures.
You may not be able to get rid of powdery mildew, but you can take steps to keep it from getting out of control. Always water at the base of the plant and keep foliage as dry as possible. Prune, if necessary, to improve air circulation, which will help by reducing humidity. Remove infected leaves and keep the area around the plant free of debris. Go easy on fertilizer in late summer, especially high-nitrogen fertilizer. Fungicide may help slow powdery mildew when applied every seven to fourteen days throughout the growing season, although the fungus is resistant to some fungicides.
A plant’s ability to survive frost or cold damage depends on climate, winter protection, and the type and hardiness of the plant. Many plants can rebound from winter-long freezes, while others will be nipped at the first hint of cold weather in autumn. Water lightly if you think a plant is damaged. Be patient and don’t take any other action if you aren’t sure the plant is dead, because many plants won’t show signs of life until spring. If you see green growth, prune and fertilize lightly to support the plant as it recovers.
Many vegetables bolt, including cool weather veggies such as spinach, leeks, onions, celery, carrots, and lettuce, as well as cruciferous vegetables such as cabbage, turnips, and collards. Bolting simply means that the plant starts to flower by rapidly sending up stalks in response to longer days and/or higher temperatures. When a plant bolts, growth slows, and the plant’s energy is focused on producing seeds. Quality is significantly diminished, and the vegetables are usually tough, woody, and bitter.
We all have questions now and then, whether long-time gardeners or those just starting out. So if you have a gardening question, get a gardening answer. We’re always here to help.