We’ve all had them. Moments when we realize that irreversible damage to a plant (or many plants) has occurred. Sometimes we can save them, and sometimes we can’t. Let’s look at some of the more common plant catastrophes and what can be done about them. Then I’ll share my plant catastrophe story. I’ll give you a hint: it has something to do with fish. Most plant catastrophes occur when plants are grown in containers, though not always. These disasters can occur suddenly or slowly over time. Crashing to the ground Potted plants are known to fall. A gust of wind, an exuberant pet, or a stray elbow can tip the scales of balance, sending a plant crashing to the ground. Containers are usually lost in these scenarios. Luckily, most plants can survive a fall. Discard the broken pottery, or you can save the pieces to cover the drainage hole in other containers. [Note: do not add a layer of shards, rocks, or gravel to the bottom of a planting container. This wastes space better dedicated to soil. A shard over the hole simply reduces soil loss.] You may want to spread out a couple of sheets of newspaper before you begin. Gently collect your fallen plant and place it on the newspaper. Then you can sweep up the soil and debris, placing it on the newspaper, as well. This is an excellent opportunity to examine the roots of your fallen plant for signs of pests and disease. You may also find that your plant has become root bound. In that cases, you can either trim back the roots or provide it with a larger pot. If pests or diseases are present, you may want to shake off any soil and toss that soil in the trash. Wash the root system under running water. Remove any damaged or diseased roots before repotting. And remember, rather than tamping the soil down when planting, which only damages valuable root hairs, mud in your plant with water. Drowning One of the most common causes of plant disasters is overwatering. It’s an honest mistake. The top of the soil looks dry. We want to care for our plants, so we water them. And then we water them again. And again. They start wilting, so we water them some more. [Plants can wilt because of too much or too little water.] What we don’t always realize is that the soil’s macropores and micropores can hold a lot of water. Those spaces are also supposed to hold air but the air is pushed out when too much water is present. Overwatering not only drowns and suffocates our plants, but it sets the stage for several fungal diseases and invites fungus gnats. More on insects below. The easiest solution to overwatering is to let plants dry out more often, provide good drainage, and invest in an inexpensive moisture meter. Underwatering On the flip side, failing to water a plant can certainly lead to disaster. Without water, plants cannot perform photosynthesis or remain upright for long. Put plant watering on a regular schedule that keeps the soil moist enough, but not too much. Again, a moisture meter is helpful. And if you know you are going to be away for a while, avoid the DIY idea of using diaper crystals to moisten your plants. It’s a bad idea. One easy self-watering idea is to place a water bottle next to the plant and lay a thin strip of cloth, paper towel, or yarn from the bottom of the water bottle to the planting soil. The soil will draw the water up the strip for as long as water is available. Insect invasions Stray stink bugs and aphid clusters are common when working with plants, but sometimes they can get out of control. This is especially true for indoor plants where pests are protected from their natural predators. Here is a list of the most common indoor pest invaders and the ways to manage them.
Many insect invasions can be thwarted by placing new plants into quarantine when they first arrive. My plant catastrophe
There was a time, many years ago, when my apartment was filled to overflowing with plants. It was lovely and I took great pride in their good health. I also had a fish tank. Every so often, I would treat my fish with brine shrimp. I would scoop the brine shrimp up with a net and deposit them in the tank. Their tiny legs would flutter in unison, caterpillar-like, as they tried escaping my fish, but they never got away. On one occasion, I must’ve gotten a bad batch of brine shrimp. When I went to feed my fish, all the brine shrimp were dead. My young adult brain said, “Well, there are lots of nutrients in those brine shrimp, so I’ll give them to my plants.” I proceeded to pour the brine shrimp into each and every one of my beautiful, beloved plants. In a very short time, I saw firsthand what happens when you use brine (saltwater) to water your plants. Most of them died. I didn’t know, at the time, that I could have saved more of those plants by removing them from their soil, washing the roots, and placing them into containers of fresh water. Live and learn, eh? What’s your plant catastrophe story?
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I learned my love of gardening as a child. It all started with a clear plastic cup, a black sponge, and four hard, dry corn seeds. When I was very young, my mother bought us educational toys. Living in rural Upstate New York before laptops existed and while televisions were still rare, these toys were a real treat. In the early 1960s, children spent nearly all day, every day playing outside. The rule was, “Come home when the street lights go on.” Those were good times. But the arrival of a package from Creative Playthings was always very exciting. A cup in a box This particular shipment was to affect me all of my life. It was nothing more than a clear plastic cup, a black sponge that fit neatly inside the cup, four hard, dry corn kernels, and a piece of paper with instructions and a place to document what I observed. I was four years old. The instructions told me to insert the sponge into the cup, which was easy enough. Then I was to slide the kernels of corn between the cup and the sponge, taking care to make sure that each kernel was pointing in a different direction. This was a little more difficult and required some patience on my part, but I recall feeling that it was important that I do this thing correctly. Nearly 60 years later, I can still feel and see the experience of pushing and prodding those seeds into position. Just add water Once my seeds were in place, all I had to do was add water and wait. Every day I checked on my seeds. Every day I checked to make sure the sponge was moist but not soggy. At first, nothing happened. I diligently noted this lack of activity on my record sheet. I’m sure I felt the same frustration and worry that I still feel at times toward slow-to-germinate seeds. But then, things started happening. The magic of germination My child-sized fingers knew how hard and pointy those corn seeds had been. To see tiny roots and shoots emerge was nothing less than miraculous. No matter which way the kernels had been turned, those first roots always knew to go down, while the first shoots always found a way to move upward, even if it took some twisting and turning. Every day, I drew pictures of what my corn seeds-turned-seedlings looked like. Eventually, we planted them outside, but I don’t think they did very well. [Corn needs to be planted in clusters that allow for wind pollination.] It didn’t matter. I was hooked. It amazed me. It still does. My first gardening experience is with me still. It taught me patience, nurturing, and good record-keeping. It left me with a sense of awe about the growing process.
What was your first gardening experience? Why do I garden? It’s a question I’ve asked myself many times. I’ve also wondered why so many people do not garden. I can’t speak to that one, but I can certainly share what I enjoy about caring for plants. Gardening is my art After many years in the Nevada desert at Burning Man, I have come to learn that everyone is creative. There are no exceptions. Some people are more connected to their art than others, but there are no uncreative people. Gardening gives me an outlet for my creativity. I look at a space and see where it could be made better, more productive, or nicer to look at. Sometimes that means adding plants and other times it means taking them away. The tabula rasa of a traditional lawn provides the canvas for a massive artichoke plant that disappears each July, a slow and steady pairing of pineapple guava and dwarf pomegranate, each with their spring blossoms and fruitful harvests. A simple backyard of lawn and shrubs can be transformed into a miniature forest of fruit and nut trees, raised beds, and a surprising amount of delicious homegrown food. That is my art. Of course, plants are always growing and changing, so what worked before might not work later on. That’s okay. I believe that the transitory nature of plants is one of the appeals of gardening.
In the garden, things are always changing. And sometimes, things don’t work out. Not enough sun, too much water, compacted soil, many things can go wrong but that’s okay, too. There’s always next year. And the year after that. Gardening gives me a chance to learn from my mistakes and try new things. Gardening is good for me Gardening is good for me physically and mentally. Working the soil improves mood. So does being outside and surrounded by nature. The bending, lifting, digging and carrying that come with gardening help me stay active and strong. I think the regular reminder of the importance of water to plant life reminds me to stay hydrated, as well. All that vitamin D is good, too, as long as I remember to wear a hat and sunscreen. Gardening reminds me that things worth having always take time, effort, and patience. And nurturing all those plants feels good, and they never criticize or judge me. Gardening builds community Gifts to friends, family, and neighbors from the home garden strengthen those bonds. Talking about gardening successes and failures brings us closer together. Sharing a harvest with those less fortunate eases everyone’s burdens. We are a social, tribal species and we are at our best when we work together toward common goals. The modern world doesn’t offer as many opportunities for that sort of work. Many people spend much of each day looking at a computer screen during the day and a TV screen at night. Gardening helps us stay connected. Gardening is good for the world Foods shipped from around the world are costly in many ways, even when they are cheaper than locally grown produce. Plants grown for storage and shipping are often less flavorful than those grown at home. And all the fossil fuels used to ship and transport those fruits and vegetables can’t be good for the air we breathe. Gardening puts me in control, sort of To be honest, one of the things I love about gardening is the sense of control it gives me. I can prune a tree into any shape I want. I can plant a row of rainbow-colored flowers if I so choose. I can try every type of radish in existence if I feel so inclined. In a world that grows ever more complicated and confusing with too many features and not enough reliable functionalities, gardening provides me with a sense of being in control, even if that feeling is fleeting and mostly inaccurate. When I garden, I eat better, sleep better, and feel better. Gardening makes me a better version of myself.
Why do you garden? While your butternut squash may be stored for a year, strawberries seem to go bad before your very eyes. The way you store your harvest can extend its usefulness and reduce waste. Peak of freshness We prefer harvesting and enjoying the fruits of our labor at their peak of freshness and sweetness. This is why my little yellow cherry tomatoes and groundcherries rarely make it into the house. Of course, if we ate everything as soon as it ripened, we wouldn’t have anything left for later, and we’d probably have a stomachache. Temperature, humidity, and time are the major factors determining freshness when it comes to fruits and vegetables. For any harvest that isn’t eaten right away, there are several things you can do to help maintain flavor and quality. Location, location, location Where fruits and vegetables are stored makes a big difference in how long they stay fresh. Some produce belongs on your countertop and some need a dry, cool, dark place. Other fruits and vegetables will stay their best in the crisper drawer, while others are best stored on a refrigerator shelf. We’ll get to the particulars in a moment. Packaging Another freshness factor revolves around the packaging materials used. This has a lot to do with ethylene gas. Ethylene gas is the chemical responsible for ripening, and some fruits produce more than others, while others are very sensitive to the ethylene produced by their neighbors. Apples, bananas, celery, and onions produce a lot of ethylene gas and should be stored away from other fruits and vegetables. Brussels sprouts, broccoli, carrots, green beans, and unripe bananas are very ethylene-sensitive and require protection. You may want to consider designating one crisper drawer for non-ethylene-sensitive produce, such as berries and citrus. That protection normally comes in the form of plastic bags and reusable containers. One of my new faves when it comes to food storage is beeswax wraps. They are cloth dipped in beeswax. They work better than I expected, and they’re good for the environment. Other containers include paper bags and damp paper towels, depending on the crop. The best way to keep celery fresh is to wrap it in a paper towel and then aluminum foil. Contrary to what you might expect, it is better if you do not wash produce before storing it. While you certainly want to brush off any soil or debris, it is better to hold off on washing until you are ready to use it. Any residual water sets the stage for rot, so be sure to dry anything you have to wash before storing. You can also extend the life of your cilantro and asparagus by storing them upright in the fridge with the cut ends in water. And remove carrot, radish, and other leafy tops before storing. Temperature matters People used ice to keep food from going bad for a very long time. The first refrigerator was built in 1834. Crisper drawers were invented one year later. Crisper drawers work by maintaining higher humidity levels than are found in the rest of the refrigerator. Most crisper drawers have closeable vents. When the vent is shut, humidity is higher. This is ideal for your leafy greens. When that vent is open, humidity levels drop. This is better for things like apples and pears. Having the vent open also releases some of the ethylene gas that speeds ripening. Perishable food is best stored at 37°F to 41°F (3°C to 5°C). These cooler temperatures reduce bacterial growth, thereby slowing rot and decomposition. That’s why refrigerators are such a good idea. But your fridge’s temperatures vary. Refrigerators have a variety of temperature zones. The front of the top shelf and the meat drawer are the coldest, making them the best places for your eggs, butter, and meat. Your apples will last the longest if stored on the back of the top shelf. The back of the middle shelf is colder than the front, making it a good place for leftovers, while the front of the middle shelf is ideal for melons and beans. The back of the bottom shelf is also a good long-term storage spot, but the front of this shelf is often the warmest part of your fridge, making it ideal for corn, mushrooms, and other cold-sensitive produce. As for the door, higher means warmer, and lower means colder. Long-term storage Before your harvest starts to shrivel or rot, decide which items need long-term storage. You can slice, blanch, and freeze summer squash. While it tends to break down with cooking, it still makes excellent additions to soups and stews long after the summer sun has left your garden. Herbs can be dried. And if you end up with too many grapes, you can always hang clusters in a corner of your kitchen, or loose on a steamer until they turn into raisins. It really works. Canning, drying, and pickling are other long-term storage options. And be sure to check with friends, neighbors, and local charities to see if they could use some of your abundant harvest.
Finally, remember the adage: when in doubt, throw it out. Or add it to the compost pile. Back when I was young and lacking enough sense to research facts before spouting Old Wives Tales, I used to tell everyone that plants grown around classical music would thrive while their twins, who had been exposed to heavy metal, would wither and die. It’s simply not true.
What is true is far more fascinating. The sound of silence We expect plants to be quiet. We’re not surprised when a seedling silently reaches for the sun. [Corn and bamboo can be exceptions to that quiet.] No matter how closely we listen, we cannot hear roots as they reach deep into the soil. You can track down videos and products that translate these biological processes of plants into sounds and music, but that’s not what we’re talking about here. Today’s topic is about the perception and production of actual sounds. Responding to sounds Somehow, without brains, ears, eyes, noses, or nervous systems, plants can perceive, respond to, and communicate visual cues, aromas, gravity, and sounds to other plants. [Did you know that even bacteria communicate with one another through sound vibrations? I didn’t either.] Many plants respond to the sound of caterpillars and other herbivores feeding by producing protective chemicals. Sound waves have also been shown to increase growth rates within some plants. One study found that sound wave treatments of 125 and 250 Hz increased drought tolerance in rice (Jeong, et al 2008). Detecting certain frequencies can also cause plants to produce growth hormones and protect themselves against microbial pathogens. Plant bioacoustics The technical term for a plant’s ability to perceive and produce sounds is ‘plant bioacoustics’. They can produce sounds in the 10–240 Hz range, as well as ultrasonic acoustic emissions (UAE) within 20–300 kHz. [We hear sounds in the 20 to 20,000 Hz range.] The sound frequencies plants produce vary, depending on the cause behind the need to communicate. These sounds are produced in the xylem, where water and bubbles of air are moved around. Scientists believe that plants produce sounds by manipulating these bubbles, something my fellow barbershop chorus friends will appreciate. In the plant world, this bubbling is called cavitation. It ends up that plants really do “scream” when they are damaged. Did you know that tomato plants stressed by drought produce an average of 35 sounds each hour? The same plants produce 11 sounds an hour when stressed by stem damage. And those sounds are different, in both volume and frequency, depending on the cause and the species of the affected plant. Apparently, drought stress is grounds for louder communication. Social interactions We know that plants can detect neighboring plants by touch. We also know that they use chemical messaging to orchestrate exchanges with soil microorganisms, trading sugars produced through photosynthesis for specific nutrients. Trees and other plants recognize family members and create social networks. If you had the proper equipment, and many mammals and insects do, you’d be able to hear those tomato plants from up to 16 feet away. It’s much noisier in my garden than I ever realized. And it’s happening underground, too. Root signaling It ends up that it takes very little energy to send sound waves through the soil. When root cells are damaged, plants generate sounds that can be detected by neighboring plants, warning them that danger may be at hand. Plants also produce sounds in the 100–300 Hz range that tell their neighbors where good food and water can be found. Your pea plant roots are actively listening for the sound of water in the soil. Buzz pollination Some insects use sound vibrations to make plants release their pollen. This is called buzz pollination or sonication. You can test this with a tuning fork. Depending on the plant species, sound waves between 40 to 1000 Hz cause flowers to expel small doses of pollen into the air. Other flowers detect the frequencies of certain bee wingbeats and respond by producing nectar that contains more sugar. We still don’t know how plants perceive sound. But researchers are currently exploring ways of using sound waves to help plants be more productive while protecting them from insect feeding. One study used sound to increase tomato crops by 13%. Wouldn’t it be nice if we could keep aphids, stink bugs, and weeds away while encouraging bigger, sweeter tomatoes? It just might happen. They are also exploring ways of use sound to reduce ethylene production so that produce is less likely to rot on the way to market. Can plants hear? They sure can. Does talking to them make them grow better? It just might. Watching my 4-month-old grandson delight in standing in his new walker, I am reminded that there are no “overnight successes” or “quick fixes” in the real world. Babies take months to learn how to stand and walk. Gardens take years to fulfill their creators’ dreams. Every success we experience, be it in our professions, health and fitness, or in the garden, all happen because of baby steps taken over and over again. Little steps add up In 2016, my son and I walked across Spain. That was a one-month, 500-mile walk. It was a wonderful experience, and not just because I got to do it with him. Learning first-hand that taking one step after another, no matter how casually, will eventually add up to something significantly bigger. Your garden and landscape work the same way. Plans, passions, and reality Most gardeners, especially those new to gardening, would love to have that picture-perfect, trouble-free, highly productive piece of earth seen in movies and magazines. The reality is, elegant botanical gardens have dozens of professional gardeners and countless volunteers who work every day to create those masterpieces. For us home gardeners, getting help like that is nearly impossible. It’s hard enough to find someone to help dispose of an old couch. [And many of those magazine garden, plant, and flower pictures are photoshopped.] But you can take your passion for gardening and your ideals and get them moving in the right direction by identifying and performing short-term goals regularly and consistently. Baby steps. Say you want a lush, productive blueberry hedge? Start by identifying the best location. Clear away the weeds. Top-dress the area with aged manure and compost. Protect the space with mulch. Conduct research about the best varieties for your microclimate. Eventually, you will install your blueberry plants. And, after a few years and regular care, your blueberry hedge will become a reality. It won’t happen overnight, but those baby steps can and will get you there. Little doesn’t mean insignificant Unless we’re talking about diamonds (and babies), small things are often seen as less-than. The truth is, it’s the little things, done repeatedly, that create practically every success. None of us is perfectly fit two months after our New Year's’ resolutions are made. But try adding squats while your microwave is running, or 10 little jumping jacks each time you use the bathroom and see just how much these tiny acts of fitness add up over time. The trick is making these baby steps easy enough to do that there’s no desire to avoid them. Trying to rid your yard of every weed in a single day is a Herculean task that may make you throw up your hands in despair and quit gardening altogether. Weeding your garden on a regular rotation will never get rid of all your weeds (nothing can do that short of Agent Oranging the neighborhood). What it will do is ensure that you are checking on each area of your garden regularly and removing most of the weeds. Over time, the weeds will be less of a problem and you won’t experience burn-out.
“Natural is better.” “Natural is safer.” These words are easy to say and they sound good, but they can be very wrong. You can’t assume that just because something is natural means it is safe. Natural pesticides can be just as deadly as chemical concoctions. Mushrooms may be natural and organic, but some of them can kill you. Even the seeds and skins of some of our common foods can cause illness or death when eaten to excess. Chemical warfare may be banned in the human world (and with good reason), but plants regularly employ chemicals to defend against insect and herbivore feeding and in response the injury and environmental stresses. Some of the chemicals they use can hurt us, too. Today we are looking at some of the natural toxins growing in our gardens and lurking in our crisper drawers. Apples, barley, and stone fruits The seeds of apples and the pits of stone fruits contain cyanogenic glycoside. When plants feel they are being attacked, they remove the sugar molecule from these compounds, converting them into hydrogen cyanide. Barley, flax, and sorghum do the same thing. Raw cassava (tapioca) and bamboo shoots also contain hydrogen cyanide. Hydrogen cyanide is a blood agent that halts cellular respiration. It will kill you if you eat too much. Cereals, dried fruits, nuts, and spices Have you ever nibbled raw cookie dough? I have. And I’ve heard that I shouldn’t. I always thought that was because of the raw eggs, but it ends up that bird poop residue is the real reason. Another problem with this food group is more serious than a short-term belly ache. Cereals, dried fruits, nuts, and spices can harbor certain molds, called mycotoxins, that can cause severe illness. Long-term exposure, while rare, can cause immune deficiency and some cancers. Herbs, honey, and sunflowers Herbs, honey, and members of the sunflower family all contain something called pyrrolizidine alkaloids. Milk, eggs, and cereal grains also contain these chemicals, which are known to cause liver damage. Borage leaf, coltsfoot, and comfrey contain particularly high levels of this natural toxin. Remember, the damage is in the dose. Kidney beans Raw kidney beans are dangerous. There, I’ve said it. I didn’t even know it until I wrote this post. It ends up that all raw beans contain chemicals called lectins. Lectins can cause severe digestive upset. Raw kidney beans contain more lectins than other beans. Low and slow cooking may be great for that pot roast, but those temperatures may not be high enough to destroy lectins, so be sure to crank up the heat for at least part of your bean cooking regime. Mushrooms Some people can forage safely for mushrooms and others cannot. I’m in the latter group. Because some mushroom species can kill you, I opt for the grocery store. Unlike some other toxins, those found in mushrooms are not destroyed by cooking. Parsnips Parsnips have a chemical arsenal of their own. When they feel threatened, they produce chemicals known as furocoumarins. These chemicals can cause stomachache and skin rashes. To avoid these problems, peel your parsnips and discard any damaged bits. And pour the cooking water down the drain, rather than adding it to your soup stock. By the way, carrots, parsley, celery root, and citrus contain furocoumarins, too. Potatoes We’ve all seen it. Just under the brown skin of a potato, you see green. These green areas occur when a potato is sprouting and when the plant feels stressed. Along with that green tinge are chemicals known as glycoalkaloids. All members of the nightshade family contain these chemicals. Mostly found in the leaves, glycoalkaloids can give you a bad belly ache. They can also kill you. Be sure to remove any green or damaged bits before cooking your potatoes. If they taste bitter, toss them in the trash. Rhubarb
I’m only including rhubarb because everyone seems to have heard how toxic their leaves are. They do contain oxalic acid. It’s also true that oxalic acid can cause cramps and interfere with breathing and heartbeats. It can also cause coma and death, but you’d have to eat a profound amount of rhubarb leaves to have a problem. Sweet potatoes Sweet potatoes can produce toxins used in defense against injury, insect feeding, and other stresses. One of these toxins, ipomeamarone, makes your sweet potatoes taste bitter. It can also kill you, so don’t eat bitter-tasting sweet potatoes and always cut out and discard damaged areas. Zucchini Bitter-tasting zucchinis may contain chemicals known as cucurbitacins. Cucurbitacins cause something called “toxic squash syndrome”. Symptoms of this condition include severe digestive upset followed by hair loss, weeks after the fact. How weird is that? With all these potential toxins in our food, what’s a gardener to do? First of all, recognize that you would have to eat an awful lot of most of these plants to cause any real harm. Second, keeping your plants healthy with proper fertilizing, irrigation, and pest and disease control reduces their need for self-defense. You can protect yourself and your family by discarding any produce that is badly damaged or moldy and cooking your food properly. The plants you see on TV and in magazines always look perfect, but real life is seldom like that. Plants rarely have perfectly rounded shapes or masses of fruit and flowers wherever you look. In real life, plants often have one side that looks and performs better. Things are uneven. Movie star plants (and their human counterparts) look the way they do because they are frequently airbrushed and staged by professionals. Imperfections are perfectly normal in the plant (and human) world. Failing to thrive is something else altogether. Failure to thrive is not a disease. It is a symptom. And most of us have seen it happen in our gardens or patios. Scraggly stems, too few leaves, little or no fruit or flowers, and overall weakness are all signs of failing to thrive. You can help your plant return to good health once you know the cause. Failure to thrive is usually an environmental or biological issue. Biological causes of failure to thrive Some plants are born weak. It can be because the seed was old, or germination occurred too early in the season while temperatures were too cold. In both cases, the seedling had to put out more energy than it could afford, too early in its growth, and may never recover fully. Other biological causes of failure to thrive include diseases and improper planting. You can prevent many problems with these tips:
Environmental causes behind a failure to thrive Plants cannot leave their environment, so they deal with wherever they are. Several environmental conditions keep plants from thriving:
Drastic measures
In some cases, you have to take more drastic measures. After all your other treatments and corrections have failed, it is time to dig up or unpot your plants and get to the root of the problem. You will want to work over a tarp or a large container. Either dig up your problem plant or remove it from its container. Shake the soil from the roots and wash them. Root washing is an excellent way to see what is going on underground. Prune out any damaged, mushy, broken, or infected roots. Set the root ball in a bucket of water and examine the soil. Look for signs of insect pupae, grubs, root maggots, root weevils, wireworms, cutworms, and other soil-dwelling pests. Smell the soil. Does it smell rich and earthy? Or does it smell funky, like old gym socks? Healthy soil contains earthworms and zillions of microorganisms. And it smells like good earth. Less-than-ideal soil smells like something rotten. If that’s the case, toss it in the trash and give your patient some fresh potting soil. Until your plant is thriving, if possible, keep it in a container in a protected location during its recovery.
Global agriculture or local gardens Whether we are talking about pandemics in the global food supply or epidemics in neighborhood home gardens, the spread of disease affects us all. Finding cures and treating sick plants takes time, costs money, and reduces crop size. Farmers and home gardeners can work to prevent these problems (easier) or deal with the consequences (harder). Plant pandemics are increasing in frequency and effect because of rising temperatures, global trade, pathogen spillover, and evolution. Rising temperatures Temperatures are rising around the world. Many pests that act as disease vectors used to die in winter. Warmer winters mean more disease-carrying pests are attacking plants, and pathogens, such as bacteria and viruses, are more active. And they are expanding their territories. Changing storm patterns, drought occurrence, and other conditions also weaken plants and favor diseases. Monitoring plants regularly for signs of trouble can help nip those problems in the bud. Global trade Travel along the Silk Road 2,000 years ago brought untold wealth and riches to the far reaches of the globe. It also furthered the development of science, literature, and medicine. And it increased the spread of diseases, such as intestinal parasites, the Black Death (bubonic plague), smallpox, and STDs (sexually transmitted diseases). Modern global trade has had similar effects on our gardens. A single pest, virus, bacteria, or other plant problem can catch a ride on a shipment of produce, furniture, or dollar store doo-dad bound for your neighborhood. Before you know it, you’re up against something new. Some of those new problems can be devastating. And many countries are forced, through poverty, to ignore trade restrictions regarding pests, diseases, and chemical use. As a result, low-priced produce often comes at a higher long-term cost.
Pathogen spillover In some cases, the carriers of diseases develop a taste for something new. Expanding food preferences are becoming more common as we craft new varieties of plants that tolerate non-traditional temperature ranges. As crops are grown in new areas, pests and diseases that favor those crops follow. Once established, those pests and diseases often develop a taste for the local flora, spilling over into these local crops. Also, where one plant disease may be tolerable, multiple diseases are often devastating. Disease evolution One thing I learned while studying for the Master Gardener’s exam was that pathogens push plants to develop better defenses. It’s one of Nietzsche’s “What doesn’t kill you makes you stronger” situations. Plants that die are removed from the gene pool, leaving more resistant specimens to reproduce. Of course, we don’t want anything to kill our herbs, tomatoes, or fruit trees. We want them to grow and thrive and produce. Like everything else, diseases evolve. A simple mutation can change everything. Insects and microorganisms evolve much faster than plants (or us). Sometimes a plant disease can have a mild effect for several years and suddenly mutate and become devastating. Common plant epidemics Monoculture and the increasing demand for food have led to the rise of several plant pandemics. These are some of the most common plant pandemics that you probably never heard about in the news:
These are only a few of the plant pandemics currently happening. Like Covid-19, many of the carriers of these diseases can be asymptomatic, which means they look perfectly healthy. But adding them to your landscape can cause years of headaches and work. Disease vectors You can reduce the risk of plant diseases causing problems in your garden by monitoring insect movements in your region. Many insects carry diseases. Knowing which insects are coming your way can help you be better prepared. The Big Bug Hunt is a good tool I’ve used to see what’s coming. I’m sure there are others, but the Big Bug Hunt has the added benefit of providing photos and identification tools. These other tips can help break the chain of plant epidemics and pandemics:
Finally, learn more about the relationships between the plants you are growing and the pests that threaten them. Did you know that green peach aphids hide and spend their winters on stone fruit trees and can then carry potato leafroll to your potatoes in spring? Now you know. Remember, the more you know, the better equipped you are to halt the spread of these and other plant diseases. We may not be able to vaccinate our garden plants to protect them (yet), but there are other things we can do. There are many reasons to grow your own food: flavor and freshness usually top the list. Pesticides are another reason. Pros and cons of pesticides Pesticides can make quick work of pests that damage our plants or carry plant diseases. They can also spread to unintended locations, contaminate groundwater, and interfere with the delicate balance of countless, often beneficial, life forms. How much is too much? How can we know these chemicals were used responsibly by growers halfway around the world? It’s tricky. Healthy produce Fresh produce is supposed to be good for us. We are urged to eat at least five servings of fresh fruit and vegetables every day. But can all the pesticides and other chemicals used in commercial agriculture be washed off? The answer is no. In many cases, pesticides are systemic, which means they are absorbed by plants. How many otherwise healthy fruits and veggies contain high levels of pesticides? The list may surprise you. Environmental Working Group The Environmental Working Group (EWG) publishes a list of the twelve U.S. crops most contaminated with pesticides. The ‘Dirty Dozen’ are often sprayed with chemicals banned in the European Union. Did you know that peppers are sprayed with 115 different pesticides? Or that spinach often contains twice as much pesticide residue, by weight, than any other crop tested by the EWG? According to the EWG’s 2023 Dirty Dozen, these crops are the worst when it comes to pesticides:
I use this information to help me decide what I will grow at home. Store-bought strawberries rarely taste as good as they look anyway, so homegrown or certified organic are the way I go. Spinach, kale, collards, and mustard greens are easy to grow and can be allowed to go seed, providing years of edible good health. While fruit trees take time to get started, they are a good investment in your landscape, and many of them can be grown in large containers. Tomatoes and peppers are regulars on my list of plants to grow, though celery has given me some trouble. I’m not completely opposed to pesticide use. It certainly has its place. There are billions of mouths to feed, and pests feel no remorse about wiping out crops. Instead of applying broad-spectrum pesticides, we can use hand-picking, sticky barriers, and other cultural practices to manage many pests. The good news On the flip side, the EWG also publishes a list of produce available in stores that score lowest on residual pesticides. This annual list is called the Clean Fifteen, and here is the 2023 list: The three plants I have found to be naturally pest-free have been almonds, apples, and bush beans. My three worst pest-prone plants have been Swiss chard, tomatoes, and pole beans, always with aphids.
Growing food at home, you have more control over what goes into your body. |
AuthorKate Russell, writer, gardener, and so much more. Archives
January 2024
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