When a plant contracts a disease, it’s one of the most mysterious things that can happen in your garden. How did it take place? Will it grow more? Will every plant I have die? How do I eliminate it? The illness triangle is a concept that is crucial to comprehending disease prevention (drawing, right). Three factors must come together for disease to occur: a susceptible plant (the host), an invading pathogen (such as a fungus, bacteria, or virus), and conducive environmental factors (such as humidity or drought). The disease cannot exist without any of these factors, so eliminating even one of them is necessary for prevention. Consider that the best defense against disease is a good attack rather than waiting for an issue to arise in your garden. The following 10 methods will help you maintain your plants healthy while removing at least one side of the disease triangle.
Examine plants carefully before buying
Avoiding the introduction of illness in the first place is the simplest strategy to reduce its impact on your garden. No one wants the added bonus of getting a disease with a new plant. Knowing what a healthy plant should look like is one of the hardest things to learn, making it challenging to determine whether the plant you desire is ill.
A few books, periodicals, and catalogs that display images of healthy specimens are a wonderful idea to gather. Avoid bringing home a plant that has insects, rotten stems, or dead patches. These issues are frequently challenging to eradicate once they become established and can readily spread to your healthy plants.
Always examine the quality of the roots of plants in addition to the crowns. Although it should be commonplace, one does not frequently observe customers doing this in a garden center. Put the plant stem in your fingers and place your hand on the earth. Shake the plant free by gently turning the pot upside down. To remove the roots from the pot, you might need to tap the pot’s edge on a hard surface. The root-ball should have firm, often white, evenly spaced roots. Not a good indicator are roots that are dark or spongy. It won’t be long before a plant with a rotten root system dies, even if the tops seem healthy.
Use fully composted yard waste
Not every component of a compost pile breaks down at the same rate. While certain materials may have deteriorated enough to be used in the garden, others may not have. Long-term high temperatures produced by thorough composting really eliminate any germs present in the material. Debris from infected plants that have not gone through this process will likely reintroduce diseases into your garden. Avoid utilizing yard trash as mulch around delicate plants and avoiding adding potentially infectious debris to your compost pile if you are unsure of the health of your pile.
Keep an eye on your bugs
Plant harm from insects goes well beyond just aesthetics. Viruses and bacteria often can only enter a plant through some sort of opening, and bug damage provides that. Viruses are really transported by some insects, who then pass them from one plant to the next. Thrips also transfer the impatiens necrotic spot virus, which has been a significant issue for commercial growers over the past ten years. Aphids are one of the virus’ most frequent carriers. Aster yellows (picture on the right) affects a wide variety of host plants and is spread by leafhoppers. Another factor that might stress out a plant and reduce its ability to resist disease is insect infestations.
Clean up in the fall
Even if you reside in a climate with mild temperatures, it is always better to clean up the garden in the fall. This is not only a wonderful approach to prevent sickness, but it’s also an excellent strategy to manage diseases that are currently present in your garden.
On dead leaves and other debris, diseases can overwinter and then attack new leaves when they sprout in the spring. If the fallen leaves are removed each fall, diseases like iris leaf spot, daylily leaf streak, and black spot on roses can be greatly diminished. If you are left stems and foliage to add interest throughout the winter, make sure to get rid of them before springtime new growth begins.
Apply the correct fertilizer
When fertilizing plants, you must exercise caution because too much of any fertilizer will burn roots, decreasing their capacity to absorb water. The plants are consequently more vulnerable to drought, cold, and heat stress. A healthier plant can fend off illnesses, whereas nutrient-starved plants are smaller and are more susceptible to leaf spots. Another approach to stress out a plant is to have too much of a certain nutrient.
Getting a soil test through your local extension agency will provide you with accurate information on nutrient levels in your soil. Without it, you would likely have to rely on guesswork when feeding your plants, which could lead to too much of one nutrient or not enough of another.
Plant disease-resistant varieties
Plants that are disease-resistant are ones that could contract a specific ailment but will resist it rather than dying from it. For instance, certain tomato varieties are designated as “VFN resistant,” meaning they are resistant to nematodes as well as the fungus Verticillium and Fusarium.
You might be let down if you start hunting for these codes on flowers because disease resistance is rarely noted on plant tags. This does not imply that all flower cultivars lack disease resistance. Many rose growers offer plants that are resistant to maladies like black spot and powdery mildew.
You can get assistance identifying the best or most resilient types of many plants from nursery workers and other gardeners. Additionally, plants and types that are resistant to specific diseases may be listed in reference books and catalogs.
Prune damaged limbs at the right time
It is preferable to trim trees and shrubs in the late winter as opposed to the spring. Infected limbs can spread illness over the winter, which will allow it to spread while the plant is dormant. Pruning in the late winter stops illness from spreading to new growth. Even though late-winter storms can result in more damage, it is still preferable to remove a damaged limb now rather than waiting until spring to do so. Always make clean, quick cuts with sharp equipment, and make sure you only remove healthy, living tissue.
Choose and site plants appropriately
The key to successful gardening is choosing plants that are suitable for your zone and location. A plant that prefers shade, like an azalea, may develop poorly and be more susceptible to pests and disease if it is placed in full sun. Once, I planted a crape myrtle with some of its leaves in the shade. Only this area of the plant was affected by powdery mildew.
Similar to a person’s immune system, plants have defenses that kick in when they are being attacked by an insect or illness. When plants are stressed, they are less able to respond to diseases or recover from them. Therefore, stressed plants are more likely to succumb to these diseases.
Water properly
It’s a good idea to water your garden, but since many diseases require water just as much as plants do, how you go about it matters a lot. Water is necessary for many pathogens in the soil and air to travel, grow, and replicate. Select watering techniques that minimize moisture on a plant’s leaf to prevent providing these diseases with a habitat they adore. Soaker hoses and drip irrigation accomplish this. Hold the leaves out of the way when you water the roots if you are watering by hand.
The least ideal alternative is overhead sprinkling because the most frequent leaf issues are made worse by wet leaves. However, if you go with this approach, water when the leaves are about to dry out quickly but the roots still have time to absorb the water before it evaporates.
Additionally, keep in mind that while giving your plants water, more isn’t always better. Some root-rotting fungus are encouraged by wet soil or containers, and these conditions can also suffocate roots, making them easy prey for the fungi.
Don’t crowd plants
Carefully consider the distance between transplanting, and monitor the spread of existing plants. Because crowded plants produce their own humidity, diseases including downy mildew, rust, and powdery mildew can flourish. This high relative humidity can be decreased by increasing airflow around your plants, which also speeds up the drying of the leaf.
Plants put too close to one another compete with one another for light, water, and nutrients, which results in poor growth. These fragile plants are more prone to attack. Diseases also sometimes spread when an infected leaf comes into contact with a healthy one, which is more common when plants are near to each other.
On plants like Phlox paniculata that are prone to powdery mildew, remove crowded, damaged, or old stalks to reduce the risk of illness. When your plants require it, dividing or rearranging them will also be beneficial.
Here are some tips for taking care of your plants in pots.
Keep in mind that the roots of plants in pots cannot access soil moisture. Despite the fact that potting soil effectively maintains moisture, pots typically dry out faster than the ground. You might need to water every day if it’s scorching outside. Don’t just sprinkling the foliage or flowers with water when watering Ensure that the dirt in the pot is receiving water.
Use a water-soluble fertilizer on occasion to fertilize plants to keep them blooming. Prior to adding water to a watering can, measure the fertilizer into the can. The force of the spray will thoroughly mix the fertilizer into the water if you fill your watering can with a watering nozzle’s “jet spray.”
Pinch off flowers as they begin to fade to encourage plants to continue blooming throughout the growing season. Additionally, doing so will maintain pots neat and presentable. You can deadhead with your fingers, a set of pruners, or a pair of garden snips.
You can still enjoy lovely plants, herbs, and flowers even if you don’t have enough space or the time to maintain a large garden or yard. The best of all worlds is planting in containers; it’s simple to develop lovely plants with little time, space, and effort.
DO hydrate plants in the morning.
The optimum time to water outdoor plants such as flowers and vegetables is before it gets too hot since the soil is cooler and the water has a better chance of getting to the roots before evaporating. By watering plants early, you may make sure they have enough moisture stored below to withstand the heat of a hot summer day.
DON’T water too frequently or too little.
It may be tempting to water the soil only slightly and infrequently enough to keep it moist, especially during hot weather. Deep root development is nonetheless discouraged by superficial surface watering. Choose a less frequent watering schedule instead, making sure the soil is completely saturated. With this technique, even when the soil’s surface appears dry, the roots are encouraged to go deep for any remaining moisture. The standard rule of thumb is to give your flowers and vegetables the equivalent of at 1 inch of water per week (and as much as double that amount in the peak of summer).
DO water plants at soil level.
Your plants’ roots will receive the moisture they require by receiving water when it is directed at their base. In order to slowly and thoroughly soak the soil and promote healthy growth, think about wrapping a soaker hose between the plants in a flower or vegetable bed.
DON’T use broadcast sprinklers.
Broadcast sprinklers are ineffective and saturate the plant’s leaves, which increases the danger of a fungal disease. When it’s hot or windy outside, a large portion of the water sprayed by this kind of sprinkler can evaporate before it even touches the plant, which results in less water reaching the plant’s roots.
DO water outdoor container plants at least once per day.
Compared to dirt on a garden plot or flower bed, earth in container gardens and flowerpots dries out more quickly. You must water more regularly as the container gets smaller. Soak the soil in the pots in the morning, and if the temperature rises to 90 or higher, do it again in the afternoon. Alternately, place an automatic plant waterer that attaches to a regular plastic water bottle and has a hollow spike. Water slowly seeps into the soil when the spike is inserted into the pot, providing the plant with a regular supply of water.
DON’T forget that trees need water, too.
Newly planted trees and shrubs should be thoroughly soaked with water two or three times per week for the first month. After then, give them a weekly drink for the rest of their first growing season. During the growing season, when rain is rare, established trees and shrubs (those are at least two years old) only need to be watered once every two weeks.
DO use a wand to water container plants.
A watering wand extends your arm’s length so you can water short, ground-level flowerpots on the ground and hanging plants overhead without having to bend over or squat. By merely applying the necessary amount of water to the plant’s base, you’ll save water and save your back.
DON’T water container plants with a jet-type spray nozzle.
While pressurized nozzles are fantastic for cleaning out sidewalks and driveways, the spray they produce can harm delicate plants like flowers and leaves. Additionally, it may disturb the soil near a container plant’s roots. If you don’t have a watering can, simply unhook the garden hose’s nozzle, connect it onto the hanging pot or container, and allow the water to trickle out slowly.
DO check moisture levels
Dry soil can be detrimental to garden plants. On the other hand, they dislike “wet feet,” which means they suffer if their roots are submerged in water without enough oxygen. It’s important to quickly examine the soil to make sure you don’t overwater because on a hot, windy day the soil’s surface may seem dry but the ground beneath may still be wet. Keep a wooden dowel on hand, place it in the soil of the garden, pull it out, and inspect it. If the dowel comes out clean, the soil is dry and needs watering. Moist soil will stick to the dowel.
DON’T Rely on Rain
Although they may require more during hot, dry times, most garden plants, flowers, and shrubs thrive when they receive at least 1 inch of water per week. Don’t rely on rain to maintain the health of your plants because it doesn’t always provide enough water for them to grow. Instead, insert a simple rain gauge in the garden and use it to monitor the amount of weekly rainfall. Water the garden extra if it only receives one inch of rain.