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How to Save a Dying Plant from These 5 Diseases

How to Save a Dying Plant from These 5 Diseases

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Often times, what you think is a dying plant, impossible to revive, is actually just a plant that’s showing signs of distress.

No doubt, it’s worrying. It’s also natural. They’re great a pretending, yet all they’re trying to do is tell you they’re in dire need of TLC.

Spot the symptoms early enough, intervene and you can nurse the plant to a full recovery.

Sometimes, all hope may be lost. You won’t know for sure unless you try to revive your plant.

Forewarning though: You may have to toss it. But before you do, get clued up on what it might be and what you can do because you could very-well find that it’ll be perfectly fine with a little love from your (soon-to-be) green thumbs.

The Symptoms of Near-Dead Plants (caused by a variety of problems)

Quick FYI: Chances are, there’s only one problem your plant has. Not multiple plant diseases.

Check the brief description in this section for the symptoms similar to what your plant’s showing. When you get an ‘aha, that sounds like what’s wrong with my plant,’ Click the ‘more info’ link to be taken to the fixes.

Summary of Different Plant Diseases and the Signs to Look for

Gray Mold

This is a fuzzy looking fungus, gray in color, sometimes more of a gray-brown shade. You’ll notice it more toward the topsoil of plants, rather than on the stems and tops of greens.

More info

Powdery Mildew

This is another fungus, only it’s white. It’ll start off as small white circles on plant leaves. They can also be seen on stems and on some fruiting plants too.

What starts off as a small white spot on a leaf will eventually grow to cover the entire leaf. It’s contagious too, so it’ll affect surrounding leaves and stems once it sets in.

In severe cases of powdery mildew, it’ll look like someone’s took a handful of flour and blew it onto the leaves covering the plant.

It looks that bad.

More info

Leaf Spot

These are brownish in color, starting off a lighter tan, then browning more the longer they’re left untreated, until eventually forming a black circle (much like a tarry substance).

They form on leaves as single spots, eventually merging into clusters. In later stages of leaf spot disease, leaves with dark spots on them will yellow then eventually start falling off early.

More info

Root Rot

The signs of root rot can be seen on plants without checking the roots. Leaves close to the bottom will yellow and/or turn brown. They might even fall right off.

Wilting will happen too because there won’t be enough nutrients to spur any growth, let alone healthy growth.

Roots should be a light shade of brown, sometimes closer to white on some plants. Never a dark brown or black. If they are, then root rot is setting in, needs fixed or the plant will die.

More info

Plant Edema

A plant affected by edema will have watery blisters on its leaves, usually on the underside, but in severe cases, they can form on the top of leaves. They’re easy to see as there’ll be lumps and bumps across the leaves, sort of like the chicken pox. Only instead of spots, it’s water spores.

It’s caused by too much water, which is either poor drainage or the plant is being watered too often or with too much water. The root system can’t handle the water, so it’s coming out on the leaves. If it’s not treated, it will lead to root rot.

More info

How to Nurse Your Plant Back to Full Health from these 5 Plant Diseases

Gray Mold (botrytis blight)

You will easily know if this is the issue. The clue’s in the (common) name, not the science one (that tells you nada). It’s gray and it’s mold. Not rocket science.

When you see it, you have a nasty problem.  Not a killer though. What it will do is drastically stunt your plants growth. That’s why you may think your plant’s on its way out.

This affects mostly fruiting plants, but it’ll also be problematic on flowering plants. It can be found on the buds and stems too (the fungus spreads on cut plants, so when you prune the stems, you could be opening a gateway for spread).

Causes of Gray Mold

The main causes are high humidity levels (93%+) combined with cooler growing temperatures (45oF to 60oF). In those conditions, spores can germinate. When they do and you clip your plants, they can spread further (through the open stems) causing an even bigger problem.

Treating Gray Mold on Plants

The bad news first – there’s no fungicide for this. Better news is you can intervene, isolate the plant and get rid of this fungus.

First, isolate the plant. Gray Mold’s a fungal disease so can spread.

With that in mind, sterilize your pruners/scissors before snipping – and after so you don’t spread it to another plant. Use rubbing alcohol (70% or higher) and just a wipe or dip will do.

With the plant isolated, you’ll can control the mold before it spreads.

For the infected plant, prune off all the affected areas. You’ll likely find the most affected parts of the plant are closer to the soil. All the parts with the fungus on it is better off burnt.

Then, there’s only one thing left to do. Increase air flow. If you’re growing indoors, use a fan blower to boost air circulation. If growing under or in a glass enclosure, leave it open or use a compact clip on fan to increase circulation.

One more thing, don’t forget that having plants growing too close together will affect the air flow. Give them sufficient breathing space.

Simply put, don’t try to grow too much in too small of a space.

Give the plant time in isolation, continue to water and feed as you would normally and prune it with sterilized equipment. Eventually, it’ll be back to normal.

Back to Plant Disease List

Powdery Mildew

Mildew’s usually associated with damp and wet conditions. With this type of mildew, it’s the opposite that attracts.

Powdery mildew prefers warm and dry conditions, which sadly for gardeners, means there’s a huge range of plants susceptible to its powder coatings.

It’s not fatal, provided it’s treated and not left to suffocate your plant.

The Causes of Powdery Mildew

Outdoor plants are more affected than indoor plants as it’s spread by the wind. The powder dust is actually thousands of micro fungal spores.

Spring time is when this becomes problematic. When temperatures are between 60oF and 80oF and humidity is higher than normal.

The other condition that adds to the problem is plants being too close together. That lessens air circulation, increasing humidity even higher. And with plants too close together, leaves can touch, making it easier for the fungus to spread.

Treating Powdery Mildew on Plants

Caught early enough, you could get rid of it just by rubbing a couple of affected leaves together to get rid of the fungus. Rarely will that be all you’ll need to do though.

The organic approach is to just prune your plant. Snip away the parts with the mildew on it. Slowly though; it is a powder and will spread by the slightest breeze. You don’t want to coat healthy leaves with this stuff.

For the parts you do remove, like with gray mold, burn it. Especially with this because it can lay dormant and survive winter conditions, resurfacing next spring. So, don’t compost your trimmings. Burn them.

For a chemical solution, there’s different fungicides, but not all are suitable. For edible plants, you’ll need a non-toxic fungicide or the crops are ruined.

Possible fungicides for treating powdery mildew include:

  • Triadimefon
  • Triforine
  • Propiconazole
  • Sulfur
  • and Potassium bicarbonate

Provided you spot the powdery mildew early on, you may find that pruning is enough of a prevention to stop the spread. If not, a fungicide can be applied.

The important thing is to get air flowing around the plant. That may mean separating plants to increase air flow or watering more (not overwatering though) to decrease the temperature.

Either way, the affected leaves should be removed and burned because powdery mildew is resistant to climate changes so can lay dormant and resurface.

Back to Plant Disease List

Leaf Spot

Leaf spot appears on plant foliage. Starting as single spots, they’ll quickly form clusters. The spots can be either bacterial (brown spot with a bright yellow ring around it) or fungal. Both types will be a tan shade to darker brown, and eventually turn black.

These spots will kill the leaves, which in turn, affects the nutrients the plant gets… causing wilting, premature defoliage and growth problems (when left untreated).

Causes of Bacterial Leaf Spot

Bacterial leaf spot is caused by pathogens. Just like we catch colds and other viruses like the flu, plants get infections too.

Watering plants from above will spread the pathogens around, affecting more leaves.

Treating Bacterial Leaf Spot

All you can do here is isolate the plant and snip off infected leaves.

For biological control, Cease® is ‘supposed to be’ effective, but I have no first hand experience with it. It’s expensive too.

The good news: Bacterial diseases in plants are rare. 85% of plant diseases are fungal, so if you’re seeing dark spots on your plants leaves, chances are, you’re dealing with fungal leaf spot.

Causes of Fungal Leaf Spot

The causes of fungal leaf spot are high temperatures and over-watering. For outdoor plants, heavy rainfall or consistent showers along with warmer temperatures cause fungal spores to develop, grow and spread.

The same can happen indoors if the temperatures aren’t ideal. Too hot and too much water.

Treating Fungal Leaf Spot

This one is fairly straight forward. Remember the causes are too much water and too high a temperature.

  • Isolate your plant first so that the fungi can’t spread to any more of your plants.
  • Snip away the leaves with the spots on them.
  • Water only when they need watering (when the soil is almost dry).
  • When you are watering, only top the soil up with water and don’t use a water can or spray making the leaves wet. As water splashes on infected leaves, the splashes will spread the fungi, causing more of the same.

You can also use a fungicide spray to control leaf spot. It doesn’t kill them, but it’ll prevent growth and spread.

Preventing a re-occurrence is best done by controlling:

  • Temperature
  • Air circulation
  • Humidity levels

Until your plant has all those at ideal growing conditions (specific to different plants), you’ll likely see it happen again.

Quick tip: If you’re growing several species of plants, group them so that each growing area has the conditions suitable for the plant.

In other words, don’t try to grow tomatoes in the same conditions as air plants. In particular, if you’re using indoor grow lights such as growing in your garage.

Back to Plant Disease List

Root Rot

Root rot takes hold fast. In as little as a week to a few, it can collapse your entire plant. It’s that serious!

The problem is, you have to spot it early before it kills your plant. That’s going to mean you need to inspect the roots.

The tell-tale signs of root rot on plants are:

  • There’s no new growth happening
  • The plant’s wilting
  • The leaves closer to the soil are yellowing and falling right off.

That’s happening because the root system isn’t working right. It’s making it impossible for the plant to get the nutrients it needs to survive.

If you see those signs on your plant, check the roots. If it’s in a pot, lift it out and if it’s the ground, you’ll need to dig a bit it to see what’s going on underground.

Healthy roots should be a light tan-shade of brown. On some plants, the roots are closer to white, or a golden color.

When root rot sets in, it’s dark brown and can even be black.

Causes of Root Rot

In most cases, root rot is caused by a lack of air circulation or from too much water. That’s the result of not enough drainage.

It can happen to indoor plants as well as outdoors. That said, outdoor plants are more likely to be affected due to water logging.

Root rot is a fungal plant disease that can be one of several:

  • Rhizoctonia
  • Phytophthora
  • Fusarium
  • Pythium
  • Armillaria (affecting trees, causing wood decay)

All types are soil-based fungi, and the majority of soils have these fungi’s already in them. Just dormant.

They become active in just the right conditions – when there’s loads of water and the temperatures are between 68oF and 86OF.

Treating Root Rot

For potted plants, take it out the soil it’s in. That’s wasted. Repot the plant with fresh soil.

Before you set the plant in though, snip away some of the rotted roots, especially if the rooting system has been compacted. That can happen to plants that have outgrown the size of pot they’re in. If that’s the case, use a bigger pot so that the roots can spread out while still leaving room for oxygen to circulate.

Next, reduce its size (if you can). The smaller the size of the plant, the less work the root system has to do. So, if you have a decent size, cut it back. Start with the leaves that’s yellowing and the connecting stems (these are likely the ones closest to the bottom).

Now, since we know that your plants root system needs water and air, there’s a simple trick to maximize both. Aerate your soil. With a chopstick! Simple enough.

As plants with root rot are suffocating because of a lack of oxygen, you need to get as much air in there as possible. For each inch, poke the soil a few times.

Don’t water it right away though. Let it dry before you add more water.

Remember this though, water it during the day or under light because that way photosynthesis can happen. It won’t happen in the dark so all that happens when you water at night and put the lights out is you wind up creating surface water. That’s only beneficial to the fungi causing the root rot.

Here’s something to keep in mind… Roots grow back fast. They only need a starting point. Prune off as much of the damaged roots as you can, keeping the lighter parts of the root system intact.

Then add less water more often, aerating the soil frequently. The soil should be near dry before you add more. And again, always water when there’s light. Early to mid-morning for plants growing in natural light. The new roots should spring up in a few days to a week.

Any yellowed or brown leaves won’t turn green, but the new leaves that come through will be. That’s how you’ll know your plant’s recovering from root rot.

The longer you stay on top if, the healthier your plant will be.

Back to Plant Disease List

Plant Edema

If you’re seeing water blisters, or lumps and bumps across your plant’s leaves, it’s a sign that the plant’s guzzling water faster than it can transpire.

Think of it as early sign of root rot.

What Causes Edema in Plants?

High humidity, usually caused by a lack of air flow, and overwatering lead to edema in plants. The root system has too much water, so the excess is coming out on the leaves.

Treating Plants Affected by Edema

The leaves with the water blisters won’t recover, so snip those off. The water can evaporate but the leaves won’t be healthy. They’ll have drowned. When it’s fixed, healthy leaves will grow back.

As plant edema is a root problem rather than specific to the leaves, it’s the plants environment that needs to change.

Specifically, air flow, humidity and the watering frequency (watering times too).

Air flow and humidity are one of the same. Boost the air circulation and you’ll lower the humidity levels. That’ll help the plant soak up and use the water, instead of it drowning until it uses it (standing water is rarely good with soil plants).

In terms of when to water it, mid-morning to noon is best if the light source is from sunlight. If using grow lights, increase the time the plant is under light, but do it gradually if you’ve been low on the light hours. You don’t want to add shock into the mix.

For low light plants, give them at least four hours under bright light so the water can be used faster.

The warmer the water gets, the faster the plant can absorb it. Using it, prevents standing water and that lets air circulate around the rooting system. That’ll prevent you from having to nurse a plant back to health after root rot has set in.

Treat it early by snipping off the water-logged leaves, aerate your soil by poking holes in it and water under good light conditions, but only when the soil’s were-near dry.

Before long, you’ll have healthy leaves shooting out again.

Back to Plant Disease List

To Wrap Things Up:

There’s plenty of things that can go wrong with one of your plants, causing you to think it’s dying. Unless it’s already dead, you can revive a dying plant. You only need to know what the symptoms are, and how to go about nursing your plant back to good health.

As most plant diseases are fungal and not bacterial, the majority of affected plants can be given a new lease of life.

The above five plant diseases are the most common, ranging from:

  • Seeing yellowing leaves with brown tips
  • Water spores forming on your plants leaves
  • Spots like black tar on your leaves
  • Or just leaves falling right off before they’ve fully matured

And… Plants wilting so much that you think they’ve no chance, when in reality, it’s the root system that’s not working right, needing oxygen and a lot less water to breathe.

In all cases, take the time to inspect your plant, notice the tell-tale signs and set about giving them the environment they need to grow strong. Just the right amount of water, enough air circulation and the right temperature which in turn, lowers humidity.

Make environment changes to your growing conditions and you’ll be able to watch as your plant begins its bounce back with much more strength.

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Tuesday 12th of January 2021

was doing some research today on pest management in gardens and I read several of your articles on managing pests in flowers. I wanted to let you guys know about a guide I wrote here:

all about Powdery Mildew. It is pretty thorough and might be something that could be helpful to your readers, if you think it might be something you'd want to link to.

Keep up the great work! -David Carver